TL;DR: Add an option that automatically keeps (or separates) the inner volume generated by a Shell, optionally offset by a user-defined clearance.
The problem that this feature will solve:
I frequently want to keep the removed volume from a shell operation. This happens most often when I’m designing two pieces that fit together, one that is an outer shell and the other that fills it. My current workflow is this:
clone the original body (by moving with an offset of 0 and copy toggled on)
shell the clone
subtract the shell from the original body
If I want to add a small gap between the inner and outer pieces (to account for clearance), then that’s even more steps, as I need a second clone with a second shell operation with a slightly different wall thickness.
Instead, I request that an “inverse shell” or “split body at shell” operation be added. The former would keep the removed portion (equivalent to my workflow above), or the latter would keep both pieces as separate bodies. Perhaps this could take the form of a pair of toggles on the existing shell operation: keep the outer shell, and/or keep the inner volume.
If you want to really knock it out of the park, you could include an option to add a clearance gap between the two pieces, which would save me a second shell operation.
What can’t you achieve without this feature?
This is not a blocker; I’ve found creative workarounds to the problem, but they’re all repetitive, multi-step processes and quite fragile if I want to go back and change something. It would greatly improve my workflow to have these operations. Thank you.
Xdrakosha’s most recent example is remarkably similar to the thing I was designing when I realized I wanted this feature. Yes, there are several ways to accomplish this result, but none of the ones I’ve found are as easy to use as the feature I’m proposing. Perhaps I’m missing some easier approach?
BTW, while the Scale tool can sometimes be used to create clearance gaps, it doesn’t work for sufficiently complex shapes because often you’ll want to create clearances on some faces and not others. Sometimes this can be worked around through careful choice of the center of scaling, but there is no general solution. Shell is better suited to this use because the faces you select for the shell operation are removed, and thus when you subtract the shell from the original object, those faces are unchanged. This useful behavior would naturally be part of the new feature I propose in this thread.
Here is yet another way fill the internal volume of a complex shelled body. This assumes one surface, like the lid of a bottle, is where you want to complete the fill. This makes for a solid body.
