Rigs of Rods: free and open source vehicle simulator that uses soft-body physics
Nice.<p>It's about typical for modern physics engines.<p>Totally rigid body physics is reasonably well solved by now. It suffers from the "boink" problem; in impulse-constraint systems, there are instantaneous changes in velocity on collisions. This looks OK for small objects and terrible for large ones. This is the main reason game simulations usually look wrong.<p>If you make everything soft, that works OK. But everything looks like Jell-O, as some early Pixar devs wrote. That's a soft-body system.<p>What's hard is doing things which have just a <i>little</i> elasticity. Which is most real-world materials. That's because you have to simulate what's happening on very short time scales, much shorter than a visual frame time. This is possible, but the compute load suddenly jumps by orders of magnitude during some collisions. That's hard for real-time systems. Also, you start to need double precision. If you don't need real time, as for film work, it's not too bad. Integration of stiff systems of differential equations is Not Fun. I used to do that stuff.<p>Note, in the video, how soft the suspensions are.