CHAPTER 6

Getting More from Your Sketches

Previous chapters have described the basic tools for sketching. This chapter takes you to the next level, teaching you about more advanced sketch tools, how to edit and manipulate sketches, and how to work with sketch text, sketch pictures, and sketch colors. At the end of this chapter, with a little practice to reinforce the tools and techniques, you should feel like you have mastered the topic of SolidWorks sketching and can handle almost any problem that is thrown at you.

Editing Sketch Relations

Delete is not an editing option. In time, you will find that this is good advice, even if you don't agree with it now. There are times to delete instead of editing, but you should delete only when it is necessary. In my own work, I sometimes go to extreme lengths to avoid deleting sketch entities, often just to stay in practice, but also because deleting sketch entities, or even features in a part, increases the likelihood that sketch or mate relationships will be broken.

The main reason to avoid using Delete is that when you are editing a sketch that has other features that are dependent on it, the dependent features may lose their references, or go dangling. Because of this, even when you can use the Delete command instead of making edits, it is still a good practice to edit instead. Deleting relations is not as critical as deleting sketch entities, unless the relations are referenced by equations or design tables.

Using Display/Delete Relations

Display/Delete Relations is your primary tool when dealing with sketch relations. It is particularly useful for sorting relations by the various categories shown in Figure 6.1. The capability to show sketch relations in the graphics window is nice; sorting them in a list according to their state makes this feature even more useful. To show the sketch relation symbols on the screen beside the sketch entities, use the menu selection View Sketch Relations.

FIGURE 6.1 The Display/Delete Relations PropertyManager

Sketch relations in the Display/Delete Relations dialog box can be divided into the following categories:

• All in this sketch. Shows all the relations in the active sketch.
• Dangling. Shows only the dangling relations. Dangling relations appear in a brownish-green or olive color, and represent relations that have lost one of the entities that drives the relation. You can repair dangling relations by selecting the entity with the dangling relation, and then dragging the red dot onto the entity to which it should have the relation.
• Overdefining/Not Solved. Overdefined relations are any set of conflicting or redundant instructions that are given to a sketch entity, and appear in red. If a line has conflicting relations, but it can still meet the requirements, it turns red. If a line has conflicting relations, and it cannot meet the requirements, it turns pink. If solving the line would result in a zero length line or some other impossible situation, it turns yellow.

  The Not Solved condition causes sketch entities to turn pink and often accompanies other entities that are overdefined. Not Solved typically refers to a dimension or relation that cannot be applied because of the conflict. The lower-right corner of the screen and the status bar show flags warning that the sketch is overdefined, as shown in Figure 6.2.

  When an overdefined situation exists, all the relations and dimensions in a sketch often become overdefined. This can look like a daunting task to repair, especially when the entire problem is caused by a single relation. Do not automatically delete everything. Instead, try deleting or suppressing the last dimension or relation that was added, or a single relation that looks suspect. You can suppress a dimension by setting it to Driven in the right mouse button (RMB) menu, and you can suppress relations in the Display/Delete Relations PropertyManager.

  FIGURE 6.2 An overdefined sketch

  

• External. External relations connect with an entity outside the active sketch. This includes the part Origin, or any model edges. The term external relations can also signify any relations outside of the part.
• Defined in Context. Any relation between features in one part in an assembly and another part is considered an in-context relation.
• Locked (Broken). External relations (outside the part) may be locked or broken to increase speed and to lock out parametric changes. There is no advantage of breaking relations rather than locking them. Both are ignored, but locked relations can be unlocked; broken relations can only be deleted.
• Selected Entities. Sketch relations are shown only for the selected sketch entities.

A setting in Tool Options controls the display of errors. You can choose Tools Options FeatureManager to find an option called Display Warnings, where you can choose Always, Never, and All but Top Level. When a sketch contains sketch relations with errors, they display as warning signs on the sketch and will propagate to the top level of a part or assembly if you have selected the Always option.

Using SketchXpert

The SketchXpert, shown in Figure 6.3, can help you to diagnose and repair complex sketch relation problems. The Diagnose button at the top creates several possible solutions that you can toggle through using the forward and backward arrow buttons in the Results panel. The Manual Repair button displays all the relations with errors in a window where you can delete them manually.

By selecting the option at the very bottom of the dialog box (Always open this dialog when sketch error occurs), you can make the SketchXpert appear whenever a sketch error occurs. To display the SketchXpert manually instead of automatically, you can access it by right-clicking in a sketch.

FIGURE 6.3 The SketchXpert dialog box

Working with Sketch Entities

SolidWorks offers several different tools to help you move sketch entities around in a sketch. In SolidWorks, it is usually recommended to keep the sketch as simple as you can, and to create patterns using feature patterns rather than sketch patterns. The following section discusses the main tools for moving and copying sketch entities.

Moving entities

Move entities enables you to move selected sketch entities by either selecting From and To points, or by typing in XY coordinates for the move. When the Keep relations option is unselected, the Move tool automatically detaches sketch segments whose endpoints are merged, as shown in Figure 6.4. If Keep relations is selected, SolidWorks moves the entities and tries to maintain the sketch relations and merged points. All the tools have a pushpin icon in the interface. You can use the tool multiple times in succession when the pushpin icon is pushed in; tools with the pushpin are deactivated after one use if the pushpin icon is not pushed in.

FIGURE 6.4 Using the Move tool

Rotating entities

Rotate entities rotates selected entities in a sketch in the same way that Move entities works. You can drag the angle or type it in manually. The green check mark icon is on the RMB, as shown in the cursor display in Figure 6.5.

The Keep Relations option does not actually keep any relations — it deletes the Horizontal and Vertical relations in the sketch, as shown in Figure 6.5 — but it does keep the merged endpoints, as shown in the rightmost image of Figure 6.5. This can be useful, especially considering how many sketch relations it would take to make a sketch move like this naturally.

FIGURE 6.5 Using the Rotate tool

Copying entities

The Copy entities tool works exactly like the Move entities tool, except that it copies instead of moving. The Copy entities tool enables you to copy selected sketch entities by either selecting From and To points or by typing in XY coordinates to place the copy. SolidWorks copies the entities and tries to maintain the sketch relations and merged points.

Scaling entities

Scale entities is one of those functions probably best left alone. This is because the results are erratic and unpredictable, particularly if there are dimensions on the sketch. This tool works on a selection of entities, particularly on an isolated selection that is not connected to other entities in the sketch. The PropertyManager for the Scale Entities tool is shown in Figure 6.6.

FIGURE 6.6 The Scale PropertyManager

Modifying sketch

The Modify Sketch tool has been available in SolidWorks for a long time, but it has been superseded by some of the newer tools mentioned previously. However, it still has some unique functionality that is not covered by any other sketch tool. Modify sketch works on the entire sketch rather than on selections from the sketch, and it works best if there are no external relations between sketch entities and anything outside the sketch. It can also work on a sketch without the sketch being active. While most feature and tool interfaces have been moved to the PropertyManager, Modify sketch still uses a dialog box, as shown in Figure 6.7, that floats in the graphics window.

FIGURE 6.7 The Modify Sketch dialog box

The Modify Sketch dialog box enables you to perform the following functions:

• Scale About. The Scaling function in the Modify Sketch tool enables you to scale about either the part Origin or the Moveable Origin. The Moveable Origin is the black origin symbol with knobs on the ends of the axes and at the intersection. The Moveable Origin can be moved and even snapped to entities that are internal or external to the sketch.
• Translate. The Translate function of the Modify Sketch tool enables you to click and drag to move the entire sketch, or to select a point and move it to a specific set of coordinates that you type in. If the sketch is dragged onto an external entity and picks up an automatic relation, then a message may appear saying that you can now use Modify sketch only for rotating the sketch because there is an external relation.
• Rotate. The Rotate function of the Modify Sketch tool enables you to position the Moveable Origin to act as the center of rotation, and to either type in a rotation angle or drag with the right-mouse button to rotate, as indicated by the cursor.

When you place the cursor over the knobs on the Moveable Origin, the cursor symbols change to indicate the functionality of the RMB. These cursors are shown in action in Figure 6.8. The cursors enable mirroring about X, Y, or both simultaneously.

FIGURE 6.8 The Modify Sketch tool cursors

Copying and pasting sketch entities

Probably the simplest way to copy sketch entities in a sketch is to select the entities and use Ctrl+C and Ctrl+V or one of the many other methods available for this purpose (such as the RMB button menu, the Edit menu, and Ctrl+dragging).

In addition to copying selected entities within an active sketch, you can also select a sketch from the FeatureManager and then copy and paste it to a selected plane or planar face (if you are not in a sketch to begin with). This creates a new sketch feature in the FeatureManager that is not related to the original, although it does maintain internal dimensions and relations. (External relations are not copied with the sketch.) This is particularly useful when setting up certain types of lofts that use several profiles that can be created from a single copied profile. Copying and pasting is a fast and effective method of putting sketches on planes.

Copying a sketch is similar to the derived sketch (addressed later in this chapter), except that with a copied sketch there is no link, and with the derived sketch the new and old sketches remain identical through changes to the original sketch.

Dragging entities

If a selected set of sketch entities has no external relations, then you can select it as a group and move it without distorting or resizing the sketch. For best results with this technique, avoid dragging endpoints — drag an actual line.

Creating a derived sketch

A derived sketch is a parametrically linked copy. The original parent and derived sketches do not need to have any geometrical relation to one another, but when the parent sketch is changed, the dependent derived copy is updated to stay in sync.

To create a derived sketch, you can select a plane or planar face, Ctrl+select the sketch of which you want to make the parametric copy, and then choose Insert Derived Sketch.

When you create a derived sketch, you cannot change its shape or size; it works like a block of a fixed shape driven by the parent. However, you can change the position and orientation of the derived sketch. Figure 6.9 shows a derived sketch and its parent. Modify Sketch is a great tool to use for manipulating derived sketches that are not related to things outside the sketch, especially for mirroring or rotating.

FIGURE 6.9 A derived sketch and its parent

Using Sketch Pictures

Sketch pictures are images that are placed in a sketch on a sketch plane. You can size and rotate the images, give them a transparent background, trace over them, and suppress them. They display as a child of the sketch in the FeatureManager. Image types that you can use as sketch pictures are BMP, GIF, JPEG, TIFF, PNG, PSD, and WMF.

To bring a picture into a sketch, the sketch must first be active. Click Sketch Picture on the Sketch toolbar (it is not there by default, and so you may need to drag it onto the Sketch toolbar from the Tools Customize Commands dialog box). You can also access this command by choosing Tools Sketch Tools Sketch Picture from the menu. You cannot use sketch pictures in assembly sketches, but you can use them in a part sketch in an assembly.

To change the size of a sketch picture, you can double-click it and drag one of the handles around the outside of the image. When the picture comes into the sketch, it is usually too big, having been sized at a ratio of 1 pixel to 1 mm. To size a picture accurately, you should include a ruler or an object of a known size in the image. If you cannot do this, the next best thing is to guess the size. Draw a line in your sketch and dimension it to approximately the size of something that is recognizable in the image, and then move the image by clicking and dragging it to lay the dimensioned sketch entity as close over the object in the image as possible.

You can rotate and mirror images, as well, using the Sketch Picture PropertyManager. Images are opaque, and you cannot see the model through them, but at the same time, you also cannot see the images through the model. They are like flat pieces of paper that are pasted to the model or hanging in space.

You can add transparency to images, either by selecting a color or by using the built-in transparency in the image file (alpha channels are only available in certain types of image files). When you select a color to be transparent, you will also need to increase both the Matching Tolerance and the Transparency value sliders, which are by default set to their minimum values.

Sketch pictures cannot be shown on a drawing associatively. The only way to do this is to capture an image of the sketch picture that is being shown in the model, and put this image in the drawing. PhotoView 360 does not use sketch pictures, either, and Decals are a separate item altogether.

Using three views

When building a model from images, it is often helpful to have three or more images from orthogonal views, similar to re-creating a part from a 2D drawing. If you have a left and a right view, it may be a good idea to put them on planes that are slightly separated so that the images are not exactly on top of one another, which makes them both hard to see. Putting them on slightly offset planes means that one will be clearly visible from one direction and the other visible from the other direction.

Each sketch picture must be in a separate sketch. Figure 6.10 demonstrates the use of multiple sketch pictures to trace the outline of a vehicle, with the partially complete model shown with the images.

FIGURE 6.10 Using multiple sketch pictures

Additionally, you can put multiple sketch pictures inside a single sketch if you want to do that. Both images show up in the FeatureManager, and both can be displayed at the same time, although you may have difficulty if you want to put them on top of one another.

Compensating for perspective

When taking digital photographs to be used as sketch pictures in SolidWorks, you have to consider how perspective affects the image. Perspective can make it difficult to size items in the foreground or background. You should be aware of this, as well as that objects at different distances from the camera will appear at distorted sizes. If you are taking the pictures that will be used as sketch pictures, you can minimize the effects of perspective by standing farther away from the object and using zoom on the camera if possible.

Estimating sharp edges

When you are drawing a sketch of an object, you are usually drawing theoretically sharp corners of the model. Real parts usually have rounded corners, so you may have to use your imagination to project where the 3D surfaces would intersect at an edge minus the fillets.

When you are reverse-modeling a part from images, you are not using an exact science. It is better than not being able to put pictures into the sketch, but there is nothing about it that can be considered precise.

Using Auto Trace

Auto Trace is an add-in that you can select by choosing the Tools Add-ins menu. Auto Trace is intended to trace between areas of contrast in sketch pictures, creating sketch entities. To use Auto Trace, make sure the add-in is activated. Activating the Auto Trace add-in activates a set of arrows at the top of the Sketch Picture PropertyManager. There is nothing to identify the functionality with the Auto Trace name. Figure 6.11 shows the Sketch Picture and Auto Trace PropertyManagers. The sliders for the Auto Trace functionality do not point out which end is high and which is low.

FIGURE 6.11 The Sketch Picture and Auto Trace PropertyManagers

Auto Trace works best with solid blocks of black and white in the Sketch Pictures. To achieve this, you may need to use image processing software and reduce your picture to a two-color (black and white) bitmap, TIF, or PNG image. Even if this pre-processing gives perfect results, don't expect much from Auto Trace.

I can't imagine a situation in which I would use this myself or recommend anyone else use it. In all cases, including idealized demonstration images or those in which traced images would be of the most benefit to the user, such as logos with complex curvature, I believe it would be faster and more accurate to do the tracing manually, even it means using splines.

Using Sketch Text

Sketch text uses TrueType fonts to create text inside a SolidWorks sketch. This means that any TrueType font that you have can be converted to text in solid geometry; this includes Wingdings and symbol fonts. Keep in mind that some characters in certain fonts do not convert cleanly into SolidWorks sketches. Sketch text still has to follow the rules for sketching and creating features such as closed contours, as well as not mixing open and closed contours.

You can make sketch text follow a sketch curve; to space it evenly along the curve, you can control character width and spacing, as well as overall size, by specifying points or actual dimensions. Sketch text can also be justified right, left, centered, and evenly, as well as reversed, rotated, and flipped upside down. Figure 6.12 shows the Sketch Text PropertyManager and some examples of sketch text options.

FIGURE 6.12 Examples of sketch text

The icons in the Sketch Text PropertyManager are self-explanatory, other than the Rotated Text option, which rotates individual letters (as shown in the Dimension the Placement Point text in Figure 6.12), and not the whole string of text.

You can use the Sketch Text tool multiple times in a single sketch to make pieces of text with different properties. Each string of text has a placement point located at the lower left of the text. This point can be given sketch relations or dimensions to locate the text.

If the text overlaps in places, as shown in Figure 6.12, you can correct this in a couple of ways. First, you can extrude it with the Merge option unselected so that each letter is created as a separate solid body. You can also explode sketch text so that it becomes simply lines and arcs in a sketch, which you can edit the same as any other sketch. You can also adjust the Width Factor and Spacing settings.

Starting in the 2010 version of SolidWorks, you can link the text to a custom property. This means that sketch text can be changed with configurations. Configurations are covered in a later chapter. The text used to extrude a feature can come from Custom Properties, which can be driven by a design table or directly through the Sketch Text PropertyManager.

Using Colors and Line Styles with Sketches

Custom colors and line styles are usually associated with drawings, not sketches; in fact, they are most valuable when used for drawings. In sketches, this functionality is little known or used, but is still of value in certain situations.

Working in Color Display mode

In drawings, you can use the Color Display Mode button to switch sketch entities on the drawing between displaying the assigned line or layer color and displaying the sketch status color. It has exactly the same effect in part and assembly sketches.

When you select the button, the sketch state colors are used. When the button is not selected, any custom colors that you have applied to the sketch entities appear. If the button is not selected and you have not applied colors to the entities, then the default sketch state colors are used.

You can use sketch colors for emphasis, to make selected sketch entities stand out, or to make sketches with various functions immediately distinguishable. Color Display mode only has an effect on an active sketch. Once a sketch is closed, it returns to the gray default color for inactive sketch entities.

Assigning line color

Line color enables you to assign color to entities in an active sketch. The Color Display Mode tool determines whether the assigned color or the default sketch status colors are used.

Using the Edit Sketch Or Curve Color tool

You can use the Edit Sketch Or Curve Color tool to assign color to an inactive sketch or to a sketch block. The color that you assign to sketches in this way displays only when the sketch is inactive, instead of the default gray color. The sketches also follow the toggle state of the Color Display Mode button. For example, if the Color Display Mode button is selected, then inactive sketches display as gray. When the Color Display Mode button is unselected, then inactive sketches display in any color that you have assigned by using the Edit Color tool.

When you use this tool to color a sketch block, the block displays the color inside the active sketch. You cannot use the Line Color tool mentioned earlier to assign color to a block.

Assigning line thickness and line style

The Line Thickness and Line Style tools function independently from the Color Display Mode button, but they are still used only when the sketch is active. As soon as a sketch that contains entities with edited thickness and style is closed, the display goes back to the normal line weight and font.

To assign a thickness or a style, you can select the sketch entities to be changed, click the button, and then select the thickness or style. Although a single sketch entity may have only a single thickness or style, you can use multiple thicknesses or styles within a single sketch. Figure 6.13 shows a sketch with the thickness and style edited.

FIGURE 6.13 A sketch with edited line thickness and line style

Using Other Sketch Tools

SolidWorks has a lot of functionality that overlaps between multiple topics. The following tools could appear in other sections of the book, but I include them here because they will help you work with and control 2D sketches in SolidWorks. Almost everybody who opens the SolidWorks software at one time or another has to use a sketch, so these tools could be applied by a wide swath of users.

Working with RapidSketch

As the name suggests, RapidSketch is meant to help you rapidly create a number of sketches on different planes or flat faces. As you move a sketch cursor over flat faces of a model, the faces highlight to indicate that you can start a new sketch there.

The workflow with this tool is that you start in one sketch, with an active sketch tool, move the cursor over another plane or face without exiting the first sketch, and start sketching the entity on the new plane.

The only real downside of using RapidSketch is that if you sketch on a particular plane or face where other planes or faces might be visible in the background, SolidWorks might interpret certain selections as trying to change sketch planes. To get back to a previous sketch, deactivate the current sketch tool (for example, by pressing Esc) and double-click the previous sketch you want to return to. To move to a later sketch, use the normal sketch exiting techniques.

RapidSketch is a rarely used function in SolidWorks. It has been available for several releases now, but it has not caught on with users. I have yet to see a compelling case for its use.

Adding Sensors

You can add Sensors in the SolidWorks FeatureManager for parts and assemblies by right-clicking the Sensors folder and selecting Add Sensor. You can find the Sensors folder at the top of the FeatureManager. If you cannot find the Sensors folder, choose Tools Options FeatureManager and make sure the Sensor folder is set to Show.

You are not limited to using sensors only when working with sketches; you can use them outside of sketches in parts and assemblies to warn you when various types of parameters meet various types of criteria.

Figure 6.14 shows the Sensor PropertyManager. You can create sensors for measurements, simulation data, or mass properties. The reason I have included Sensors in this chapter is the measurement options, which enable you to select a dimension and set a range of values or criteria for which you want to be notified. The dimension can be a driving (black) sketch dimension, a driven (gray) dimension on a sketch, or even a driven dimension placed directly on solid geometry.

FIGURE 6.14 The Sensor PropertyManager

FIGURE 6.14 shows what happens when a sensor finds a condition that you asked it to notify you about.

In addition to turning Sensor alarms on or off, you can also suppress Sensors when they are no longer needed or to improve performance.

Sensors are a great way to keep an eye on particular values, such as wall thickness or clearance between parts. You can use a Sensor to monitor any value you want to monitor but don't drive directly.

Using metadata for sketches

Metadata in SolidWorks is non-geometrical text information. Metadata is particularly helpful as keywords in searches as well as in Product Data Management (PDM) applications. If you don't use metadata within your CAD documents, it can be easy to forget that it is there at all.

You can use the following items as metadata in SolidWorks files:

• Sketch and feature names
• Sketch and feature comments (access comments via the RMB menu)
• Custom Properties
• Design Binder documents
• Tags for features (located on Status Bar in the lower-right corner)

Metadata searches can be particularly useful in large assemblies or parts with long lists of features that you need to find or search through. You can conduct searches for metadata through the FeatureManager Filter at the top of the FeatureManager. The Advanced Search function in assemblies can also search metadata sources. SolidWorks Explorer is a good first-level data management solution that can search, display, and edit metadata and previews. Windows Explorer can also search properties and tags.

Creating construction geometry

In SolidWorks, the only construction geometry that can be created directly is the construction line. All other sketch entities can be converted to construction geometry by selecting the Construction Geometry option within the sketch entity's PropertyManager or by using the Construction Geometry toggle toolbar button.

SolidWorks terminology is inconsistent, because it sometimes refers to construction lines as centerlines. The two are really the same thing. Centerlines are used for revolved sketches and mirroring, but there is no difference between a centerline and a construction line in SolidWorks.

Construction geometry is useful for many different types of situations. I use it frequently for reference sketch data. You can make sketch relations to construction geometry and can use it for layout sketches or many other purposes limited mainly by your needs and imagination.

Sketching in 3D

The 3D sketch is an important tool for creating weldments (and many other features) in SolidWorks. Structural frames are a large part of the work that is typically done using weldment functionality in SolidWorks, and frames are most often represented as 3D wireframes. You can do this with a combination of 2D sketches on different planes, with a single 3D sketch, or with a combination of 2D and 3D sketches. If you have confidence in your ability to use 3D sketches, then that is the best way to go. Three-dimensional sketches can be challenging, but they are certainly manageable if you know what to expect from them.

Earlier chapters discuss the tools that are available for 3D sketches; this chapter covers techniques for 3D sketching.

Navigating in space

When drawing a line in a 3D sketch, the cursor and Origin initially look like those shown in Figure 6.15. The large red Origin is called the space handle, with the red legs indicating the active sketching plane. Any sketch entities that you draw lie on this plane. The cursor also indicates the plane to which the active sketching plane is parallel. The XY graphic shown in Figure 6.15 does not mean that the sketch is going to be on the XY plane, just parallel to it.

FIGURE 6.15 The space handle and the 3D sketch cursor

Pressing the Tab key causes the active sketching plane to toggle between XY, YZ, and ZX. The active sketching plane indication does not create any sketch relations; it just lets you know the orientation of the sketch entities that are being placed. If you want to create a skew line that is not parallel to any standard plane, you can do this by sketching to available endpoints, vertices, Origins, and so on. If there are not any entities to snap to, then you need to accept the planar placement, turn off the sketch tool, rotate the view, and move one end of the sketch entity.

An excellent tool to help you visualize what is happening in a 3D sketch is the Four Viewport view. This divides the screen into four quadrants, displaying the Front, Top, and Right views in addition to the trimetric or isometric view. You can sketch in any of the viewports, and the sketch updates live in all of the viewports simultaneously. This arrangement is shown in Figure 6.16. You can easily access the divided viewport screen by using buttons on the Standard Views toolbar. You can also manually split the screen by using the splitter bars at the lower-left and upper-right ends of the scroll bar areas around the graphics window. These window elements are also described in Chapter 2.

When unconstrained entities in a 3D sketch are moved, they move in the plane of the screen. This can lead to unexpected results when viewing something at an angle, moving it, and then rotating the view, which shows that it has shot off into deep interplanetary space. This is another reason for using the Four Viewport view, which enables you to see what is going on from all points of view at once.

FIGURE 6.16 The Four Viewport view

Exploring sketch relations in 3D sketches

Sketch relations in 3D sketches are not exactly the same as in 2D sketches. Improvements have been made in the past several versions, but 3D sketches still lack some important bits of functionality. Pierce is not applicable in a 3D sketch, and is replaced by Coincident, because in 3D sketches there is no difference between Pierce and Coincident. Relations are not projected into a plane in a 3D sketch the way they are in 2D.

On the other hand, several other relations are available in 3D sketches that are not found in 2D sketches, such as AlongX, AlongY, AlongZ, and OnSurface.

As mentioned earlier, relations in 3D sketches are not projected like they are in 2D sketches. For example, an entity in a 2D sketch can be made coincident to an entity that is out of plane. This is because to make the relation, the out-of-plane entity is projected into the sketch plane, and the relation is made to the projection. In a 3D sketch, Coincident means Coincident, with no projection.

As a general caution, keep in mind that solving sketches in 3D is more difficult than it is in 2D. You will see more situations where sketch relations fail, or flip in the wrong direction. Angle dimensions in particular are notorious in 3D sketches for flipping direction if they change and go across the 180-degree mark. When possible, it is advisable to work with fully defined sketches, and also to be careful (and conservative) with sketch relations.

For example, the sketch shown in Figure 6.17 cannot be fully defined without also overdefining the sketch. The main difficulty is that the combination of the tangent arc and the symmetric legs of the end brace cannot be located rotationally, even using the questionable reliability of 3D planes that are discussed next.

FIGURE 6.17 Three-dimensional sketches may be difficult to fully define.

This set of sketch entities cannot be located rotationally within the 3D sketch

Using planes in space

It is possible to create planes directly in 3D sketches. These planes work like regular planes starting in SolidWorks 2010, where they are defined by constraints and selections rather than selecting a type of method to define a plane. Sketches can be created on these planes, and move with the planes. Having planes in the sketch also enables planar sketch entities such as arcs and circles in 3D sketches.

Unfortunately, there is a lot to watch out for with 3D planes, as they are called. The first thing to watch out for is that they do not follow their original definition like normal Reference Geometry type planes. Figure 6.18 shows the PropertyManager interface for creating 3D planes; however, keep in mind that the plane does not maintain the original relation to these initial references. The parent-and-child relations that SolidWorks users are used to are suspended for this one function, or work in the reverse from what you normally expect.

3D planes cannot be fully defined unless there is some sketch geometry on the plane that is in turn related to something else. Limited types of sketch relations can be applied directly to the plane itself, Horizontal and Vertical relations cannot be applied directly to the plane to orient it. Horizontal and Vertical relations of entities on the plane are relative only to the plane and not to the rest of the part, and so making a line horizontal on the plane does not mean anything when the plane rotates (which it is free to do until it is somehow constrained to prevent this).

Beyond this, when a plane violates a sketch relation, the relation is not reported, which severely limits the amount of confidence that you can place in planes that are created in this way. The biggest danger is in the plane rotating, because that is the direction in which it is most difficult to fully lock down. The best recommendation I can make here is reference sketch lines given some relations to something stable, preferably outside of the 3D sketch.

FIGURE 6.18 The 3D planes PropertyManager

If you choose to use these planes, to activate the plane for sketching, you can double-click the plane with the cursor. The plane is activated when it displays a grid. You can double-click an empty space to return to regular 3D Sketch mode. The main thing that you give up with abandoning 3D sketch planes is the ability to use the dynamic drag options when all loft or boundary sketches are made in a single 3D sketch, which I have never used except to demonstrate the idea once.

Using planar path segments

Some path segments that are allowed in 3D sketches can only be used if they are sketched on a plane. These entities include circles and arcs, and can include splines, although splines are not required to be on a plane. It has already been mentioned that to sketch on a 3D Plane (a plane created within the 3D sketch), you can simply double-click the plane.

To sketch on a standard plane or reference geometry plane, you can Ctrl+click the border of the plane with the sketch entity icon active, or double-click the plane. The space handle moves, indicating that newly created sketch entities will lie in the selected plane.

Defining dimensions

Dimensions in 2D sketches can represent the distance between two points, or they can represent the horizontal or vertical distance between objects. In 3D sketches, dimensions between points are always the straight-line distance. If you want to get a dimension that is horizontal or vertical, you should create the dimension between a plane and a point (the dimension is always measured normal to the plane) or between a line and a point (the dimension is always measured perpendicular to the line). For this reason, reference sketch geometry is often used freely in 3D sketches, in part to support dimensioning.

Using 3D sketch summary

Three-deminisional sketches are extremely powerful for many different applications. The problem is that they are also limited in some of their capabilities, and they do not work exactly like 2D sketches. You will benefit from knowing how to use 3D sketches at some point, even if it isn't every day.

Tutorial: Editing and Copying

This tutorial guides you through some common sketch relation editing scenarios and using some of the Copy, Move, and Derive tools. Follow these steps to learn about editing and copying sketches:

1. Open the part named Chapter6 Tutorial1.sldprt from the DVD. This part has several error flags on sketches. In cases where there are many errors, it is best to roll the part back and go through the errors one by one.
2. Drag the rollback bar from just after the last fillet feature to just after Extrude3. If Extrude3 is expanded so that you can see Sketch3 under it, drop the rollback bar to after Sketch3. If a warning message appears, telling you that Sketch3 will be temporarily unabsorbed, select Cancel and try the rollback again. Figure 6.19 shows before and after views for the rollback.

   FIGURE 6.19 Rolling the part back to Extrude3

   

3. Edit Sketch3 and deselect the Sketch Relations display (View Sketch Relations). Relations with errors will still be displayed. Click Display/Delete Relations on the toolbar (the Eyeglasses tool), and set it to All in This Sketch. Notice that all the relations conflict, but only one is unsolvable: the Equal Radius relation. This appears to be a mistake because the two arcs cannot be equal.
4. Delete the Equal Radius relation. Select the relation in red and click the Delete button in the PropertyManager. (You can also press the Delete key on the keyboard.) The sketch is still not fixed.
5. Click the green check mark icon to close the Display/Delete Relations PropertyManager.
6. Right-click the graphics window and select SketchXpert; then click Diagnose.
7. Using the double arrows in the Results panel, toggle through the available solutions. All the solutions except one remove sketch relations. Accept the one solution that removes the dimension. This is shown in Figure 6.20.The sketch no longer shows errors in the graphics window, but it still does in the FeatureManager.

   FIGURE 6.20 Using the SketchXpert to resolve an overdefined sketch

   

8. Close the sketch. Notice that the error flag does not disappear until the sketch has been repaired and closed.
9. Use the rollback bar to roll forward to after Extrude2 and Sketch2. Figure 6.21 shows the tool tip message that appears if you place the cursor over the feature with the error. With time, you will begin to recognize the error messages by a single keyword or even by the shape of the message text. This message tells you that there is a dangling relation — a relation that has lost one of the entities.

   FIGURE 6.21 A tool tip gives a description of the error.

   

10. Edit the sketch (see Figure 6.22). If you show the Sketch Relation icons again, the errors will be easier to identify. When you use Display/Delete Relations (Tools Relations Display/Delete Relations), the first two Coincident relations appear to be dangling. Clicking the relation in the Relations panel of the Display/Delete Relations PropertyManager shows that one point was coincident to a line and the other point was coincident to a point.
11. Click the name of the dangling entity in the Entities panel of the PropertyManager; then click the vertex indicated in Figure 6.18 in the Replace box at the bottom. When you have fixed the errors, exit the sketch and confirm that the flag is no longer on Sketch2.

    An easier way to repair the dangling relation is to click on the dangling sketch point once. It will turn red. Next, drag the point onto an entity that you want to reattach the relation to.

12. Exit the sketch.
13. Drag the rollback bar to just before CutExtrude1. Edit 3DSketch1. This sketch is overdefined. If the Sketch Relations are not selected at this point, then select them again.

    Tip

    Because selecting and deselecting the display of the sketch relations in the graphics window is a task that you will perform many times, this is a good opportunity to set up a hotkey for this function. As a reminder, to set up a hotkey, choose Tools Customize Keyboard, and in the Search box type relations. In the Shortcut column for this command, select a hotkey to use.

14. Double-click any of the relation icons; the Display/Delete Relations PropertyManager appears. Notice that one of the sketch relations is a Fixed relation. Delete the Fixed relation, and exit the sketch.
15. Right-click anywhere in the FeatureManager and select Roll To End.
16. Click CutExtrude1 in the FeatureManager so that you can see it in the graphics window and then click a blank space to deselect the feature.

    FIGURE 6.22 Fixing dangling errors

    

17. Ctrl+drag any face of the cut feature, and drop it onto another flat face. The Ctrl+drag function copies the feature and the sketch, but the external dimensions and relations become detached. This will only work if Instant3D is unselected.
18. Click Dangle in response to the prompt. This means that you will have to reattach some dangling dimensions rather than re-creating them. Edit the newly created sketch, which now has an error on it.
19. Two of the dimensions that went to external edges now have the olive dangling color. Select one of the dimensions; a red handle appears. Drag the red handle and attach it to a model edge. Do this for both dimensions. The dimensions update to reflect their new locations. Exit the sketch and verify that the error flag has disappeared.
20. Expand CutExtrude1, and select Sketch5 under it. Ctrl+select a flat face on the model other than the one that Sketch5 is on. In the menu, choose Insert Derived Sketch. You are now in a sketch editing the derived sketch.
21. The sketch is blue, and so you should be able to resize it, right? No, it doesn't work that way for derived sketches. You can test this by dragging the large circle; it only repositions the entire sketch as a unit.
22. Dimension the center of the large circle to the edges of the model.
23. Drag the smaller circle, and notice that it swivels around the larger circle. Create an angle dimension between the construction line between the circle centers and one of the model edges. Notice that the sketch is now fully defined.
24. Exit the sketch, and look at the name of the derived sketch in the FeatureManager. The term derived appears after the name, and the sketch appears as fully defined.
25. Right-click the sketch and select Underive Sketch. Notice that the sketch is now underdefined. The Underive command removes the associative link between the two sketches.

Tutorial: Controlling Pictures, Text, Colors, and Styles

This tutorial guides you through some of the miscellaneous functions in sketches, and shows you what they are used for and how they are used. Follow these steps to learn how to control these items:

1. Open a new part using a template with inches as units. Open a sketch on the Front plane and draw a construction line starting from the origin 12 inches down (negative Y) away from the Origin.
2. Insert a sketch picture in this sketch. Use Sketch Picture 1.tif from the DVD for Chapter 6.
3. Resize the image so that the endpoints of the construction line are near the centers of the holes on the ends of the part. To move the image, just double-click it first, and then drag it. To resize it, drag the corners.
4. In the Transparency panel of the Sketch Picture PropertyManager, select the Eyedropper tool and click in the white background of the image. Make sure that the color field next to the Eyedropper tool changes to white.
5. Slide the Transparency and Matching Tolerance sliders all the way to the right, or type 1.00 in the number boxes.
6. Close the sketch, and rename it Sketch Image Front View.
7. Put the image Sketch Picture 2.tif, also from the DVD, in a sketch on the Right plane, and resize it to fit with the first image. Center it symmetrically about the Origin. Also, set the transparency to the same setting as the first image.
8. Open a new sketch, also on the Front plane, and draw two circles to match the features on the ends. Extrude them using a Mid Plane extrusion to match the image in the other direction (about 2.5 inches), as shown in Figure 6.23.
9. Open another new sketch on the Front plane and draw the tangent lines to form the web in the middle of the part. Use the automatic relations to draw the lines tangent to the two cylinders. It is easiest if you the Front View for this. Close the sketch to make a solid extrusion. Extrude this part .5 inches Mid Plane.
10. Open a new sketch on the face of the large flat web that you created in the previous step, and offset the arc edge of the larger circular boss by 2.10 inches.

    FIGURE 6.23 Using sketch pictures

    

11. Change the arc to a construction arc and drag its endpoints to approximately the position shown in Figure 6.24. The endpoints of the arc are blue after you drag them. Give them a Horizontal relation, and then dimension them.

    To create the 2.10 dimension as shown, select the arc and circle with the Dimension cursor while pressing down the Shift key.

    FIGURE 6.24 Creating an offset arc

    

12. Choose File Properties. Make sure the Custom tab is active, and type Sketch Text in the first open box of the Property Name column. Make sure the Type is set to Text, and in the Value field, type SolidWorks. Click OK when you are done.
13. Choose Tools Sketch Entities Text to initiate the creation of sketch text.
14. Select the construction arc to go into the Curves window.
15. Below the Text window, click the Link to Property button. Select Sketch Text from the drop-down list. Select the Full Justify option, then click the green check mark icon to accept it.
16. Deselect the Use Document Font option, click the Font button, and then set the Units to .50 inches. Click the Bold button to make the text thicker. Click OK to exit the dialog box. Click the green check mark icon to exit the sketch text, and then exit the sketch.
17. Extrude the text to a depth of .050 inches with 3 degrees of draft. The part at this point resembles Figure 6.25.

    Performance

    Sketch Text is a real performance killer. The more text that you use, the longer it takes to extrude. Draft on the extrusion adds to the time required.

    FIGURE 6.25 Creating extruded text

    

18. Select the flat face on the other side of the part from where you just extruded the text, and open a sketch.
19. Select the face and click the Offset button to make a set of sketch entities offset to the inside of the face by .50 inches. Remember that you may have to reverse the offset to get it to work properly.
20. Open the Line Format toolbar (right-click any toolbar other than the CommandManager and select Line Format).
21. Select all the sketch lines and change their color using the Line Color tool. Change the line thickness and the line style using the appropriate tools. The sketch now looks something like Figure 6.26.
22. When you click the Color Display Mode tool, the colors return to regular sketch colors. When you exit the sketch, the line weight and style also return to normal.

    FIGURE 6.26 Using line thickness and line style

    

Tutorial: Using Metadata

If you integrate the use of metadata into your company's modeling process, your SolidWorks models can be a resource for much more than just geometrical data. In this tutorial, discover the hidden treasure of extra information stored as metadata in this model.

1. Open the part from the DVD called Chapter 6 – Dial Cover.sldprt.
2. Check the Custom Properties in this file by choosing File Properties. Notice the Thickness and Process properties in particular. All the metadata entry interfaces are shown in Figure 6.27.

   FIGURE 6.27 Metadata entry interfaces

   

3. Add a Custom Property with the Property Name Material, type Text, and value ABS. The Custom Property interface is located at File Properties.
4. Check the Comments in this part. Notice that a Comments folder exists near the top of the FeatureManager. Inside it is a list of the features for which I have written comments.
5. Add a Comment by right-clicking the VarFillet3 feature, selecting the Comment flyout arrow, clicking the Add Comment option, clicking the Date/Time Stamp button, and adding a comment that uses the word Blend.
6. Check the Tags for the part by clicking the small yellow tag in the lower-right corner of the Status Bar, then click any feature, and double-click in the Tags interface box.
7. Add a Tag by selecting the Cut-Extrude1 feature and adding the tag pilar.
8. Right-click any item in the FeatureManager and select Go To from the options.
9. Type 37 in the box and click the Find Next button. The FeatureManager should highlight a feature near the bottom of the tree named Fillet37.
10. Click Fillet37 in the Feature Manager and select the Zoom to Selection tool. Zoom to Selection is a magnifying glass with an equal sign in it. The display zooms and pans to a fillet on one end of the part.
11. Right-click a face of Fillet37 on the model and select Go To Feature (In Tree), which will select the FeatureManager if necessary and scroll to show Fillet37. This sequence of tools shows the importance and interdependence of feature names and the actual geometry.
12. Type the word Thickness in the filter at the top of the FeatureManager. Figure 6.28 shows the result. Notice how quickly the results appear. Notice also that the metadata item that caused the feature to show in the list can be shown in a tool tip by hovering the mouse over the feature.

    FIGURE 6.28 Using the FeatureManager Filter to search for metadata

    

13. Click the X at the right end of the filter to restore the FeatureManager to its original state, and type the word Pilar instead. Now filter for Thermoform.

Tutorial: Sketching Calculator

Sketches can be used as geometrical calculators. Parametrics can be extremely powerful when you can define relationships between geometry. In this tutorial, you will set up a sketch to calculate the complex size and location relationships between the rings of a child's stacking toy.

1. Open a new part document with inch units.
2. Draw a pyramid with the base centered on the origin, as shown in Figure 6.29. Do not use dimensions, but use sketch relations and construction geometry to enable it to change symmetrically.
3. Draw three circles to the right of the pyramid. The bottom circle should be tangent to the bottom and the angled side of the pyramid. The middle and top circles should be tangent to the lower circle and the angled side of the pyramid, respectively. Figure 6.30 shows this process partially completed.

   FIGURE 6.29 Build a pyramid without dimensions.

   

   FIGURE 6.30 Sketching stacking rings

   

4. Put a diameter dimension on each circle. In the PropertyManager for each dimension, rename the dimension for ring1dia@Sketch1, ring2dia, and so on. This is shown in Figure 6.31.
5. Place a dimension from the center of the bottom circle to the construction line, and place the dimension on the far side of the construction line from the circle. This creates a diameter dimension.
6. Place a dimension for the middle circle in the same way as the bottom circle, but this time, make the dimension value about 75 percent of the first diameter.

   FIGURE 6.31 Naming dimensions

   

7. Complete the sketch as shown in Figure 6.32, with all the dimensions and sketch relations.

   FIGURE 6.32 The finished sketch

   

8. Make changes to the sketch to see which changes it will allow and which it will not. Double-click dimensions and use the wheel in the middle of the Modify dialog box to apply changes smoothly. Try changing each dimension.

Summary

Many tools that are available in sketches are not commonly covered in the most popular sources of information, including official training manuals. The difference between a good CAD tool and a great communication tool can be minor functions that just make life a little easier, or the presentation or editing of data a little better. When you explore the capabilities of SolidWorks, it usually rewards you with functionality that is not immediately obvious.