By Clint Brown
I was recently asked about Surface areas and how they are calculated in Assemblies and Shrinkwraps.
The question really was why is the surface are of an Assembly file significantly more that the surface are of the Assembly Shrinkwrap?
The answer is that the Assembly file is calculating the surface area of all parts, and then adding them together to form the total surface area. To prove this, I did a small experiment:
Part 1 has a surface area of : 1545.664 mm^2
Part 2 has a surface area of: 1336.748 mm^2
Assembly 1 has a surface area of: 2882.411mm^2
This area is the sum of the areas of part1 and part2
If we do a Shrinkwrap of the assembly, the surface area of the resulting part is: 2505.420mm^2
So where does this leave us? Well, if we were looking to paint an object, the Shrinkwrap is the most accurate Surface area, however the total assembly surface area is what is shown in the assembly by default.