KinematicBody as part of joint crash

[Lax]

Hi Julio,

I found a weird crash. I'm using a spaceship model as kinematic body. On that ship there is a cannon (body), which uses a hingejoint with the spaceshipe (kinematic body) as parent.

Now after my simulation is ended I get a crash in

NewtonBodySetMatrix(m_body, &matrix[0]);

because internally, the body pointer is *.

When I use a usual body for the spaceship and create the joint, everything does work as expected.
So it has something todo, that a joint is mixed with body and kinematic body.

Do you have a clue, what is happening here?

Best Regards
Lax

[Julio Jerez]

Kinematic bodies are not allowed to be linked to other bodies by joints.
For that there is the kinematic joint.

Make the ship a dynamic body.
Then add at kinematic joint.
Then you control the body by setting the target matrix of the kinematic joint

[Lax]

Ahh ok. The strange thing was, that it worked, the hinge could be rotated^^. The crash occured on destruction. And because of that, I thought, that it will work.

Thanks for clarification!

[Julio Jerez]

I works on some cases but that's because some loophole in the engine logic. there probably some assert you are ignoring. Kinematic bodies are designed primarily for triggers in 3.14. they do not get dynamics updates only collision. so the behave like object attached to static bodies.

in 4.0 they are the actual base class for all objects, so joints can be attached to them, but 4.00 is too young still to be use in production.