Through the past year I've been experimenting with constraint vehicles in Blender Game Engine, simulating each wheel, chassis and axles as separate rigid bodies, connected by constraints, and got some nice results. By now I made three cars with different suspension types, using only physical primitives and 6-dof constraints. No extra hacks. I didn't even used anisotropic friction (as yet).
Making this project, I'm thinking not only about the game. But also want to make a set of tools for easy making constraint cars rigs in blender, as powerful animation tool. Like Craft Director Tools, or MadCar for 3Ds Max.
So, here is it:
How to play: http://sourceforge.net/apps/mediawiki/b ... ow_to_play
I'm writing here in hope to get some feedback and support. So, here is my issues:
1) In spite the really stable behavior on high speed (up to 200kmh), rig have some oddity at low speed. It's barely noticeable in Uaz car, and much more visible with other two. From time to time wheels can stick in middle air, and car goes like in convulsions. Sometimes, going on low speed, car can even overturn around rear wheels for no reason. That's nasty glitch! And I despaired, having no idea what it's caused by.
2) As I know, not all bullet constraints functional implemented in BGE. I didn't found right way to set damping for springs, so I decided to use linear motor with zero speed. Unfortunately, Spring and motor can't be on same axis in one constraint, so I end up with two constraints per spring. One for spring, and one for damping. I doubt, it's not a best way to do damping. Hope to find a better one.
3) I'm looking for a way to make collision between wheels and ground more elastic. I'll try softbody just for fun, but it's not a solution. Is there a way to get elastic collisions with physical primitives?
4) The spring force is linear to joint position? I'd like to make it parabolic.
5) And lot's more, but enough.
I'll be glad to get any suggestions, or constructive critic.
I'm also looking for similar projects with constraint vehicles on bullet, and didn't found much. If you know any, please, give me a link.
Thank in advance and sorry for my poor English.