Hi @CemilYuksel, I saw your file. I thought there was a precision issue, but there is not. The difference between the values you expect C3D to give you and the ones you have in the Excel spreadsheet is caused by the Curve Tolerance Correction you activated. Once you deactivate the Curve Tolerance Correction the values are those that you expect.
1. With curve Tolerance

2. Without Curve Tolerance

The decimals you see result from C3D's computation with all the decimals measured in the section view. When we measure areas and compute volumes manually, we might drop a few decimal places that, in the end, make a small difference in the final result.
I personally don't use this curve tolerance since I have not been able to find enough material to understand how C3D does this correction. If I cannot see how the program does that, I prefer to avoid it. What I prefer is to create more sample lines to add precision to my computation instead of using curve tolerance.
I hope this helps. Best regards!
Camilo Fernández
P.Eng | Transportation
