UNDERSTANDING ABOUT Edge Tolerances and Vertex Tolerances

Rhino Rhino for Windows
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1

Hello Rhino users.

I am not Rhino user but i need to exchange datas between Rhino 7 and Creo 9.

I don’t understand well tolerances calculation during modeling in Rhino.

I have the impression that a local tolerance exists or that the resulting tolerance on an object depends on the operations.

I have to work in absolute tolerance 0.001 in creo and some rhino objects have errors. However, they are simple parts.

If i read object description in rhino for example : Edge Tolerances: 0.000 to 0.007 and Vertex Tolerances: 0.000 to 0.007

But in other objects i can read for edge tolerances:

0.000 to 0.008
0.000 to 0.003
0.000 to 0.002
0.000 to 0.014

The objects must be compatible with creo’s tolerance but that does not work.

Do you have a solution in rhino 7 to reduce error.

Thank you cery much

2

Perhaps this document will help some:

https://wiki.mcneel.com/rhino/faqtolerances

If you need to hold a 0.001 tolerance in Creo, I would set a tolerance of maybe half that in Rhino - since in certain operations Rhino can automatically double the absolute file tolerance to make things work. Also make sure you are not overriding the set modeling tolerances by using commands like JoinEdge which can force edges out of tolerance.

3

Sounds like OP is dealing with Rhino files that are supplied to him by Rhino users for his Creo work. The advice would need to be passed on to them. Who knows how receptive they would be? :slightly_smiling_face: