Extruding Shapes with Coincident Corners

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1

When trying to extrude shapes from a surface by sketching a grid directly on a body and then extruding different cells, I found that when there are coincident corners, a separate body gets created. These bodies cannot be combined in a Boolean operation.

The only way I found to fix this was to create either a small gap, or an overlap to remove the coincident edges. On the actual model, this created a lot of model complexity that caused failure during modeling and had issues exporting to an STL (to solve the export issue I created a custom Resolution where I increased the deviation until it would export).

The issue occurs both on my iPad and my PC.

I’ve managed to work around the problem (for one object, I had to export to a different tool, perform some edits there and re-import as a mesh) and complete the project, but this is a significant limitation when trying to create a surface texture on objects.

Is this a known issue? Is there a fix?

The example attached here shows the issue on a simplified model.

Extruding with Coincident Corners Issue.shapr (42.6 KB)

IMG_0201
IMG_02011920×1341 153 KB

IMG_0202
IMG_02021920×1341 144 KB

2

I believe you are creating new body, if you click on little box icon choose Union instead of New Body.

Also when you create a new box, its trying to also union with the box next to it with zero distance so you get an error.

image
image936×528 71.2 KB

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3

It’s a known behaviour. Non-manifold bodies not allowed in Shapr3D. Only thing you can do is modify these kind of objects as you’ve described yourself.

4

Also every other 3d CAD program will give you this error as well. Note that screenshot was from FUSION 360.

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