Cinematic joints on dynamic body

[zak]

I am thinking to do a ragdoll with only one dynamic body and with compound collisions that simulates joints.
They are cinematic joint fixed on dynamic body. So we can have a dynamic body that changes shape.
Let's imagine a spider with eight legs. With dynamics we have 16 joints and 17 bodies,
with this idea 1 body and no dynamic joints. Yes, it responds on external contacts hard,
but with the right procedural algorithms, cinematic joints can looks realistics.
Pro is performance and absolute precision (no disarticulations even with extreme velocities)
It can be done also with 2 o 3 dynamic bodies end every one with several cinematic joints for more realism.

To do this it is necessary to change matrix of collisions on body when it needs
or can be done with joints of dynamic-cinematic bodies
(dynamic body moves and cinematic body is fixed on it with the rules of the cinematic joints)
and joints of cinematic-cinematic bodies.
It is possible to do this with Newton as is now?

[JoeJ]

I think it should be possible to do that now, but it will not work well.
The problem is if you change the transformation matrix between 2 bodies, resulting in a penetration with the ground for example,
Newton does not know what force created that motion. So it can't calculate the opposite force.
Instead the error correction will resolve the penetration with constant speed (in the best case - if it will not recognize any velocity, it will do nothing).