Large Assembly Management - Absolute Tolerance

Question

Starting with Creo 7 PTC changed the start parts to have absolute tolerance instead of relative tolerance because of multibody. I am aware of the topics on this board discussing absolute vs relative. I am curious as to whether anyone has done any studies about whether this has impacts on large assembly management.

Chris3 · Accepted Answer

Coming back to this, I spoke with several admins at the last PTC User about making the switch and while no one had hard data anecdotally everyone seemed to agree it was a good move if for nothing else then solving accuracy failures at the part level (ie large part with small features).

tbraxton · Answer

It is accuracy not tolerance you are referring to, this is important for the sake of this discussion as tolerance has meaning in the context of Creo models as well. PTC should have made absolute accuracy the default decades ago.

Absolute accuracy vs. relative accuracy. In short if you have data sharing features among models and/or manufacture from your models (Pro/Mold etc.) you should have been using absolute accuracy all along.

I have no direct comparison data as I have been using only absolute accuracy since Pro/E 11 ca. 1994. I have worked on many assemblies with hundreds of parts. I do not think the performance hit would be in assembly mode, the part mode regeneration will dominate in almost all cases. You can easily test this with your own models by changing from relative to absolute accuracy.

Sign up

Please use your PTC eSupport account.

Welcome to the PTC Community

Please use your PTC eSupport account.