Shell - Non-Manifold inputs

[Anonymous]

When I try to shell the body, I get the message:

"The attempted shell operation had non-manifold inputs. Try with manifold inputs. I've attached my part."

I researched this problem on the forums but still haven't solved my problem. I've checked my model and all sketches are constrained and don't see any errors. I'm a newbie so I'm missing something. Attached is model. I'm trying to shell at .07" and selecting the bottom of the four legs to hollow out the body. 

Appreciate any help out there. Thanks

[LT.Rusty · Accepted solution]

Your problem is where I've added the red circles below.

You have lumps meeting along a single edge.  Make the meeting area larger, rather than just the single edge, and the shell will work out just fine.

That said, I don't know what manufacturing process you're planning to use here, but I think you're going to have a really difficult time making this part in the real world ...

[johnsonshiue · Accepted solution]

“Hi! As LT Rusty already indicated, this is a non-manifold body. “Non-manifold” means an edge is shared by more than two faces. Normally each edge is shared by two faces. When an edge is shared by more than two faces, Inventor cannot properly manage the offset faces. As a result, an error comes up. The attached image shows the area affected by non-manifold condition. You can easily recreate the condition by creating two boxes touching each other on an edge or a vertex.

I personally do not think geometry modeler should get in the way of shape creation. The modeler, in theory, is supposed to allow users to create any geometry without much restriction. If determining manufacturability is required, it should be a separate process analyzing the geometry and providing users feedback. Popping up an error in this case may not help much.

Thanks!”

Many thanks!

Johnson

[Anonymous]

Thanks so much for your time detecting the problem. I'm an artist and this part is part of an assembly of other parts that will go together to make a sculpture. example here: https://www.youtube.com/watch?v=hjpMLDG6kjA

As you to your question about how it will be produced, it's going to be made on a industrial 3d printer (fortus 250mc) that prints the part in abs plastic and the supports for the overhangs in pla. Then the part goes in a bath that dissolves the pla supports. 

[Anonymous]

thanks

[JDMather · Accepted solution]

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@Anonymous wrote:

.... it's going to be made on a industrial 3d printer..... 

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You could separate those corners by any distance, a distance far less than any manufacturing process tolerance (including 3D printing) and then it will shell.  The 3D printer will never know the difference.

[Anonymous]

thanks