We're nearing the end now. The puzzle blank has been built and been shrunk a little bit so that it works in the real world. Now to shape it like the sun model and make three more. Fortunately, this is going to be very easy:
After a moment, the puzzle piece should effectively disappear. Where did it go? It's still there, but it's now shaped exactly like the part of the sun face it covered.
See? There it is—perfectly printable flat bottom and everything. Now, to make the other three pieces, continue with the following steps:
Because the Pivot Center was switched to the 3D Cursor earlier, the rotation happens around the middle. Also, because the pieces were designed well, they should interlock perfectly with just a little gap between them.
If the rotation is askew, it may be because the 3D Cursor has moved. Undo (Ctrl + Z) the duplication, recenter the 3D Cursor (Shift + C) and try again.
In Blender, the complex math behind the Boolean modifier sometimes fails to work properly. Sometimes, it's because there are errors in the geometry of either object or the geometry is too complex. A sculpted object has very complex geometry. So, it's possible that the Boolean modifier doesn't perform as expected. If that happens, here's a list of things to try to fix it:
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to reflatten the bottom. If this works, remember to edit the other pieces so that they all match.Usually, one of these actions, or a combination of them, will kick the Boolean modifier into working, and your model will be complete.