Skip to main content
K
khimani_mohiki15-Moonstone
15-Moonstone
May 8, 2019
Solved

Assembly accuracy, relative or absolute

  • May 8, 2019
  • 4 replies
  • 3141 views

About 18months ago we changed our default part template to Absolute Accuracy, our Assembly Template has remained at Relative. Im interested in what effect it would have to change the Assembly template to Absolute accuracy, what are the pros and cons? Any input is much appreciated.

Best answer by Chris3

I don't think there is an increase in chance of failure.

 

Paccar told me:

"We use relative accuracy. Our division that designs engines (castings) uses Absolute accuracy by default in their start parts…all other divisions that bring in their designs complain about performance"

 

There are other folks that say they haven't had issues. More reference:

https://community.ptc.com/t5/Part-Modeling/Relative-vs-Absolute-accuracy/td-p/190209

 

Also I don't know what version you are using but be aware that PTC made some changes in Creo 4 to how accuracies are handled. I had issues with an early build of Creo 4 that I (maybe incorrectly) pinned on the accuracy changes they made.

4 replies

Chris3
Chris321-Topaz I
21-Topaz I
May 8, 2019

The quick and short feedback that I have received from talking with other companies on this topic is that absolute works fine when all of the parts are absolute and you have relatively small, simple assemblies.

 

If you have large assemblies and mixed absolute / relative inaccuracies then there can be a performance hit.

K
khimani_mohiki15-MoonstoneAuthor
15-Moonstone
May 8, 2019

As we only moved to Absolute part accuracy recently we have a lot of legacy parts still in relative accuracy and a lot of users create new parts by evolving existing parts using Save-As.

 

So perhaps we would see a difference in loading performance but is there any chance of regeneration failure in assemblies, we don't use any assembly level features and we position all parts using co-ordinate systems, we don't use any geometry-to-geometry assembly constraints?

Chris3
Chris321-Topaz IAnswer
21-Topaz I
May 8, 2019

I don't think there is an increase in chance of failure.

 

Paccar told me:

"We use relative accuracy. Our division that designs engines (castings) uses Absolute accuracy by default in their start parts…all other divisions that bring in their designs complain about performance"

 

There are other folks that say they haven't had issues. More reference:

https://community.ptc.com/t5/Part-Modeling/Relative-vs-Absolute-accuracy/td-p/190209

 

Also I don't know what version you are using but be aware that PTC made some changes in Creo 4 to how accuracies are handled. I had issues with an early build of Creo 4 that I (maybe incorrectly) pinned on the accuracy changes they made.

P
PTCModeratorEmeritus
Emeritus
May 8, 2019

Hello @khimani_mohiki

 

If the above post resolves your issue or answers your question, please mark it as an Accepted Solution. This will help ensure other community members with the same question can quickly find an answer.

 

Thank you both for your contributions to the PTC community!

 

PTCModerator
 

Terms & ConditionsAccessibility statement