Issue with merging parts - Bug or Misunderstanding?

jeremy_temple

I love Onshape as it's a fairly simple CAD software I can use on anything for free, but I've been having this issue occasionally that really bugs me. Sometimes, when creating multiple sections from the same sketch which I intend to add/merge together, I get an error and end up having to add them as separate parts. They can't be merged with a boolean afterwards, either. Am I missing something, or is this just a bug in the software? Thanks for any guidance

Example of issue:

https://cad.onshape.com/documents/bb7cd2a369b39c9849b631e9/w/b1042b1ccb477f9412e05642/e/0ba5e7798fdd5ed743791384?renderMode=0&uiState=6674936d98483144c0717590

 

nick_papageorge073

From the screenshot it looks like it’s probably non-manifold geometry. It means surfaces come to a sharp edge/point in a nutshell. No cad system can do that, it’s not mathematical possible. 

Go through your sketch and re-do it and it should work. 

S1mon

@nick_papageorge073

No Parasolid based CAD system can do it. The Granite kernel that Creo uses can handle these types of non-manifold situations, but they are only so useful as they don't represent something which is manufacturable.

rick_randall

@jeremy_temple

I believe it's the inner circle that's giving you the error, you might try changing it to a construction line (highlight and type "Q"), or deleting it (it's function is not really apparent to me)

Hope this helps, good luck