Thanks for the interest in the engine!
Do you have a tutorial on how to integrate skinned models with bEPU? I want to combine our animations with the physics. Is it possible?
It is possible, but there is no complete tutorial/demo at the moment.
For ragdoll-driven skinning, the concept is pretty simple. The physics entities of the ragdoll define the state of animation bones. The offsets from entities to bones in bind pose are set up offline.
Blending animation into physics is a little trickier. If it needs to be fully dynamic with graphics matching physics collision, you could motorize the ragdoll. Each joint would try to reach its target pose defined by the animation, but external forces could modify the way the ragdoll reacts. Tuning the motors' strengths would be a good idea to prevent extremely rigid movement and problems where a blocked arm pushes the entire torso over. Some core entity (pelvis) would need to be anchored to the 'character' position if it needs to stand up well.
Fully physical approaches will put a load on the solver. This won't be much of an issue on the PC, but the Xbox360 would have a harder time (somewhere between 3-8 physical characters would work on the Xbox, most likely, depending on their complexity). Given the highly articulated nature of ragdolls, the Space.SimulationSettings.CollisionResponse.Iterations may need to be increased. This takes a little extra CPU time to perform more accurate calculations.
It could also be approached in a less realistic way. The ragdoll's pose could be blended with whatever the desired animation pose is to produce some intermediate result. Obviously, collisions wouldn't be exactly right since the graphics are separated from the ragdoll, but it might help when trying to add little details to a death animation or something. The 'physical' approach and this approach could be combined, as well.
There may also be times when the physics entities should be driven by the animation completely. In this case, changing the entities to kinematic entities (entity.BecomeKinematic) would allow their velocity/state to be set without worrying about external forces. Changing their CollisionRules may also be useful, since kinematic entities will push any dynamic entity out of the way. If the entities can't collide with anything due to their collision rules, it could be left dynamic with IsAffectedByGravity set to false to prevent them from ragdolling. Using the bone-to-entity offsets calculated earlier, the entities can be positioned properly relative to the current animation pose.
Are you considering an IK system? I noticed you had Jacobian in the documentation. Probably wouldn't be too much of a stretch to add IK.
Yes, but there are some higher priority features that need to get done in the short term (a significant redesign of many parts of the engine is in progress). Any IK-related features will probably take at least 3 months.
