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Measure Volume Discrepancy/Inconsistency

Measure Volume Discrepancy/Inconsistency

Measure Volume Discrepancy/Inconsistency

(OP)
I'm stumped by an error I am experiencing in Part Design (V5-6R2014) and I am hoping one of you experts here can help me understand. I already searched the FAQ to no avail. I got some good suggestions from the COE forum, but still haven't gotten to the bottom of the problem.

I've attached a snapshot that illustrates the situation.

The part I am working on is a long thin metal strip (60 x 1 x .071) and when I measure the volume I get a number, but when I split the strip into pieces using some planes and measure the total volume (using multi-select), the returned volume is different to that of the un-split part. The error shown in the attached example is pretty minor (5.602 cu. in Vs. 5.603 cu. in), but I want to know why the numbers are not exactly the same.

The possible causes that have been proposed, tested but failed are:-
1) Unit precision: Although the example shown has a discrepancy that might be attributed to a rounding error, increasing decimal places did not change anything
2) 3D Accuracy: This was an interesting one. It was thought that coarse tesselation was responsible for the error. I tested using a full range of 3D Accuracy values to no avail.

I'm wondering if the .071" thickness in a 60.00" part in space is causing V5 accuracy tolerance to be tested to its limit.

RE: Measure Volume Discrepancy/Inconsistency

Hi,

I had a similar situation reclaimed by one of the users and the cause was the precision set different on 2 workstations. In your case I suppose CATIA will round the value for a whole solid and each of the split solids will be rounded also, so summing the values for each solid is very possible to obtain that difference.

Regards
Fernando

https://picasaweb.google.com/102257836106335725208
https://picasaweb.google.com/103462806772634246699...

RE: Measure Volume Discrepancy/Inconsistency

(OP)
Thanks, Ferdo. Perhaps it is indeed the case that the combined rounding is causing the error.
All the partbodies involved have been modeled on the same workstation and by the same user/login with the precision remaining the same throughout.

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