How to add a force inside a joint ?

[greg2fs]

Hi, in the past I used ode (or something els, not sure) and there was the possibility to add a force or torque to a joint (like a motor do between his axis and body) instead of adding it to the body itself, is it possible with newton ?
I tried with a hinge, to add a torque to the first body and substract the opposite torque to the other body, and it seems to work exept when the joint reach its limits, here the bodies start accelerate as it mustn't.
Any idea ?
Thanks

[Julio Jerez]

Netwon 1.5 thsi is no possible, but in

Netwon 2.0 adding forces and torque from inside a joint call back is a pefectly allow.
It is a feature that is used extensivatly in the demos. Specially with unit joints which I call controllers.

[greg2fs]

OK... rrrr... is there a solution for my problem with joint limit ? Or an alternative waiting for the sdk2 (I don't see download link to) ?

[Julio Jerez]

The download Links are here
viewtopic.php?f=9&t=4922

I do not know what you mean for the limits.
The joint will do what you want limits or no limits. Limits in Newton are no implemented as special code.
body reaction of the floor is suggested to forces, and the body do not penetrate the ground, similarly when you set a limits in a joint, the joint will calculate the reaction force to prevent the violation of that limit.

The only thing different between 1.5 and 2.0 is that 2.0 now allows the application to apply external forces to the bodies jointed by a joint from the joint callback function.

There is a practical way to make smart joints, like Comptroller, a power joints tha are not controlled by desired joint acceleration.