Hello, I would like to reduce/merge the number of surfaces to as little as possible because I find that this is why my simulation on grasshopper do not seems to response all the time i toggled it to true.
Hello - please export a small portion of the file and post that - it looks like you have converted one or more meshes to polysurfaces, which will always be complex unless you properly reverse engineer the meshes to surfaces, which might or might not be a simple process, more often not. You might try ToSubD in V7.
Hello - there is not an awful lot you can do here - if the objects are for visualization, the pipe objects can be curves with piping applied (ApplyCurvePipiing) rather than surfaces or polysurfaces. You may also be able to BooleanUnion these into polysurfaces in some cases, or use meshes and Join the meshes.