Create an alignment from a polyline. Creating alignments based on polylines is a traditional method of building engineering models. With Civil 3D’s built-in tools for conversion, correction, and alignment reversal, it’s easy to use the linework prepared by others to start your design model. These alignments lack the intelligence of crafted alignments, however, and you should use them sparingly.
Master It Open the MasteringAlignments-Objects.dwg file, and create alignments from the linework found there.
Solution From the Home tab and Create Design panel, select Alignment Create Alignment From Objects. Select the lines and arc.
Create a reverse curve that never loses tangency. Using the alignment layout tools, you can build intelligence into the objects you design. One of the most common errors introduced to engineering designs is curves and lines that aren’t tangent, requiring expensive revisions and resubmittals. The free, floating, and fixed components can make smart alignments in a large number of combinations available to solve almost any design problem.
Master It Open the MasteringAlignments-Reverse.dwg file, and create an alignment from the linework on the right. Create a reverse curve with both radii equal to 200 and with a pass-through point at the intersection of the two arcs.
Solution
1. Trace both lines with Fixed Segments.
2. Use the Floating Curve (From Entity With Passthrough Point) tool to draw an arc from the endpoint of the line with a pass-through point at the intersection of the two sketched arcs.
3. Use the Floating Curve (From Entity With Passthrough Point) tool to fillet the floating curve created in step 2 and the last fixed segment using a 200′ radius.
Replace a component of an alignment with another component type. One of the goals in using a dynamic modeling solution is to find better solutions, not just a solution. In the layout of alignments, this can mean changing components out along the design path, or changing the way they’re defined. Civil 3D’s ability to modify alignments’ geometric construction without destroying the object or forcing a new definition lets you experiment without destroying the data already based on an alignment.
Master It Convert the reverse curve indicated in the MasteringAlignments-Rcurve.dwg file to a floating arc that is constrained by the following segment. Then change the radius of the curves to 150′.
Solution
1. Select the indicated alignment, and right-click to edit alignment geometry.
2. Select the Alignment Grid View tool.
3. Starting with the first segment, click in the Tangency Constraint field and change it to Constrained By Next (Floating). Repeat for the other segments except the last one, which cannot be modified because it is dependent on the previous constraint.
4. Change radius of the two curves to 150′.
Create alignment tables. Sometimes there is just too much information that is displayed on a drawing, and to make it clearer, tables are used to show bearings and distances for lines, curves, and segments. With their dynamic nature, these tables are kept up-to-date with any changes.
Master It From the Mastering Alignments-Table.dwg, make a line table, curve table, and segment table. Use whichever style you want to accomplish this.
Solution For lines:
1. Click on the alignment.
2. From the Alignment contextual tab and Labels & Tables panel, select Add Tables Add Line
3. Using the Pick On Screen icon at the bottom of the dialog, select the line segments of the alignment. If a warning comes up regarding child styles, select the “Convert all selected label styles to tag” mode. Click OK.
4. Place the table anywhere on your drawing.
5. The bearings and distances are now replaced by tag labels.
For curves:
1. Click on the alignment.
2. From the Alignment contextual tab and Labels & Tables panel, select Add Tables Add Curve.
3. Using the Pick On Screen icon at the bottom of the dialog, select the curve segments of the alignment. If a warning comes up regarding child styles, select the “Convert all selected label styles to tag” mode. Click OK.
4. Place the table anywhere on your drawing.
5. The bearings and distances are now replaced by tag labels.
For segments:
1. Click on the alignment.
2. From the Alignment contextual tab and Labels & Tables panel, select Add Tables Add Segments.
3. In the By Alignment section, select the alignment you want to label. Click OK.
4. Place the table anywhere on your drawing.
5. The bearings and distances are now replaced by tag labels.