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Full Version: Imported 3rd party step file behaves oddly

From: fcwilt
9 Nov 2019   [#1]
Hi,

For starters I am a new to MOI.

I imported a 3rd party STEP file and it seemed fine.

See attached.

After it was imported it behaved like a single object. Selecting it worked as expected, the entire object highlighted.

But after working with my project for awhile something happened and now the imported object is a bunch of separate parts.

What did I do to cause that? I cannot put them back together using the boolean union command for some reason.

Thanks.

Frederick

Attachments:
Mosquito Hotend.zip


From: Michael Gibson
9 Nov 2019   [#2] In reply to [#1]
Hi Frederick, in this case that's actually a bug that the initial import behaves as one single object. It has what are called "disjoint shells" in it which means that it's configured as if it was a single solid but the list of faces in the solid do not all touch each other.

It looks like there is some problem with the structure of the file, I get some open surfaces instead of closed solids when importing into several other CAD programs like Rhino, ViaCAD, and eDrawings.

It's not intended that a single "B-Rep" object should have disconnected face islands like that (except for the case of a void cavity inside a solid), and when you do some other operations it will get fixed at that point to have different connected chunks separated out into different objects.

After the initial import if you select one face and use Edit > Separate on it, that should fix it to be separate parts like it is supposed to be.

- Michael
From: fcwilt
9 Nov 2019   [#3] In reply to [#2]
Hi,

Thanks much.

So it wasn't me - that is good to know.

The model serves it's purpose giving me the visual I need in my printer design.

Frederick