The physics engine Havok’s Primer does not clearly state whether or not one can model character for use inside Unity by way of starting off with some polygon primitives then working them into a single beautiful mesh, or if one must start off with a polygon plane and build from there. Some ambiguity remains on the effects of poly-modeling, whether or not it can adversely affect collisions and deformities.
In essence, if I had 2 models, both completely identical down to the last vertices, but one was constructed starting off with primitives while the other was constructed starting off using polygon planes, would there be a difference in the physic’s performance?
Personally, I feel it does not matter, but I need a definite answer to the question. Please help, I would be very grateful.
Not sure why you’re referencing the Havok physics engine as Unity uses PhysX but no matter.
How a mesh is built doesn’t matter to a game engine, if it’s identical down to the last vertex then it’s the same mesh. If you’re after a reason then think of the pipeline between the editor and Unity and how you could use an exporter like Obj which pretty much only contains the vertices and polygons, throwing away all of the history, and at that point the two build methods would produce the exact same file. Even using one of the formats which doesn’t throw away history doesn’t make any difference, Unity won’t use that information for anything.
With regards to physics/collision detection though things are a little different. Normally you’re not using the same mesh you’re using for display for collision detection, it’s going to have far too many polygons to be processed quickly enough, instead you use a simplified collision volume which is approximately the right size and shape but far simpler. Often these volumes are simple shapes which the collision system can be optimised for, such as spheres, boxes, and capsules, and if something more complex is needed then a simplified mesh can be used. Here though how this simplified mesh was built doesn’t matter, idenitcal meshes are the same collision mesh.
Thank you very much for your reply. This solved a lot of questions. The confusion came from one member of the team thinking one thing, while the others noticed nothing to raise red flag yet no solid answers for either side could be found. Thanks again!
