Wrong Volume Calculation

[JH_11346936]

Hello,

I am using Creo Parametric 9.0.8.0 with Windows 10. I have an odd case where it appears that Creo is measuring the volume of a part wrong. The volume output from the mass properties dialog box is showing a value of about 0.306 in^3 as shown in one of the screen shots. However, this way underestimates the volume of the part. Just the main portion in the middle can be hand calculated to about 0.7 in^3. I don't know what is wrong here. I have tried regenerating the part and swapping to fully assigned properties and then back to geometry defined, but the number does not change. Any insight is appreciated.

Thanks,

[tbraxton]

Post the model for evaluation. There are many things that could cause the results to be unexpected as you show in the screen shots. It is unlikely that Creo is in error here. It is most likely that Creo is reporting what the user has requested.

[JH_11346936]

Hi,

Here is the part file.

Thanks,

[kdirth]

Looks reasonable to me.  I also modeled to print with revolve with similar results - 0.336.

My simple calculation:

[BenLoosli]

I get a .3385 volume in Creo 9.0.9 without the internal cuts.

[tbraxton · Accepted solution]

The calcs look reasonable to me with a cursory check of the geometry. Are you certain your manual estimate of volume is accurate?

Your model is using relative accuracy (not an issue in this context). You should not be creating/using models with relative accuracy in Creo 7+. If you are using legacy start parts you should immediately change them to absolute accuracy.

[JH_11346936]

How do you update to absolute accuracy?

Thanks,

[BenLoosli]

In Creo, File-Prepare-Model Properties

Third item from top of the window is Accuracy.

[tbraxton]

1. For Creo Parametric: Select File > Prepare > Model Properties > Accuracy > change
2. Select Absolute
3. Enter desired value
4. Click Regenerate Model

Absolute accuracy has units of length so consider the value you assign in the context of how your parts are made and the tolerances of the manufacturing processes. If you set it unnecessarily low, then it will increase your regeneration time for models.