Hello all, We have had a prototype made that holds a load of water - made on solidworks. The prototype holds 7.5 ltrs of water, and we're happy this performs correctly. I had a look at the CAD model today and tried to simulate the volume by subtracting the water container from a solid body. I assume what is left is the volume of the tank.... Right? I thought so too, but the CAD model shows a volume of 7.25 ltrs, while the prototype - made from the same CAD model and checked for dimensional correctness holds 7.5 ltrs.... So... I'd like to know if the way i'm working out the volume in solidworks is wrong, or its the way solidworks is calculating it... I'll run through the steps i take below: To be honest, i'm not holding out much hope that it's not my fault, but am curious - the dimensions match, but the volume doesnt.... (by the way, the volume in this example above turned out to be correct....) Anyone had any similar problems? Cheers, Pete

Probably in the first case you forgot the top surface (the lid) and subtracted that as well.. not sure really Cheers