Creo 2.0 radius lower limit

[acoates]

Hello,

I'm trying to create a radius along an edge 3,000 mm long. I am being told by Creo that I cannot enter a value lower than 0,30, but I would like to use 0,25. Is it to do with the minimum radius setting being a percentage of the edge length? How do I fix this please?

Many thanks.

[MartinHanak · Accepted solution]

Andy,

you have a long model (3000 mm) and small radius. Therefore you have to change model accuracy from relative to absolute and find appropriate value.

Martin Hanak

[acoates]

Thanks Martin. When I go into "Prepare model" I can only specify a new relative value (currently 0.0012). How to I determine absolute, please?

[MartinHanak]

Andy,

put the following options into config.pro and restart Creo.

ENABLE_ABSOLUTE_ACCURACY yes

Martin Hanak

[RonSt.Pierre]

file > Prepare > model properties

Within the model properties window, select change to the accuracy row

Within the accuracy window, use the pull down menu on the left; two choices - absolute or relative. Pull down on right, insert value (0.01mm or .0004 IN is standard automotive practice) select Regenerate Model then close the model properties window

in your config, be sure to add

ENABLE_ABSOLUTE_ACCURACY yes

[acoates]

Thanks Chaps, I'm getting there slowly, but not I'm quite there yet.

I have absolute working as an option. The default value was ~0.3. I have tried to enter in 0.01 as suggested (unless I've misinterpreted?) but the following error occurs:

What is this value actually linked to when relative (a percentage of the maximum edge length in the model?) and what is it driving when absolute, please?

Many thanks,

Andy

[RonSt.Pierre]

You may want to use/set the following in your config.pro

default_abs_accuracy 0.01

accuracy_lower_bound 1E-04

[MartinHanak]

My config.pro contains:

accuracy_lower_bound 1E-06

default_abs_accuracy 0.002

Martin Hanak

[acoates]

Assuming that my thinking below was on the right lines, I tried your settings first, Martin, and the absolute has worked (although my relative still defaulted to 0.0012).

Many thanks to you and Ron for your help.

[acoates]

Thanks again guys. I take it that smaller numbers mean a higher shortest edge : longest edge ratio can be achieved?

[RonSt.Pierre]

As I understand it...

Relative is a tolerance based on a percentage of distance

Absolute is a tolerance of accuracy with no regards to distance applied

[acoates]

Cracking, thank you.

[dgschaefer]

Relative accuracy is the ratio of the longest edge to the smallest allowed edge. That's why small details fail on large parts.

Absolute accuracy is the absolute limit on the shortest edge allowed. It is, therefore, units dependent.

It's possible that it's not edge related but feature size related, I don't recall for sure,but the general concept still applies.

[RonSt.Pierre]

Thanks Doug for the clarification.

I can go home now, I learned something new today!!!

[acoates]

Excellent, thank you Doug.