I had a quiz in my Engineering 3 class this morning, and we were given a relatively simple part to create. I created the part, but when checked, the mass was off by approximately 0.29 grams. I had my instructor created the part correctly on my computer for me to compare mine with. Mine is on the left, and his is on the right.
I rolled back to before the extruded cut, and both parts were exactly 3891.9325 grams.
After the extruded cut was made (through all, both directions), the left part is 3845.7601 grams and the right part is 3845.7205 grams. (This slight error is compounded by the circular pattern.)
Both sketches are identical. In fact, I copied the right sketch into the sketch in the left window and found no change in the mass calculation.
While this is an extremely small difference, there must be a reason for it. Both parts have identical geometric relations and dimensions, that I can tell. My only guess is that SolidWorks is calculating the mass of the parts differently based on how the original sketches were drawn.
(Complete Parts Below}
Any help/insight is greatly appreciated!