HingeJoint 3D Motor Velocity - How to reverse direction

digitorus

I am running Godot 3.1.dev (windows, built from source on github). It seems that 3d physics hinge joint only support positive values for the motor velocity through the inspector. To reverse motor direction I am having to rotate the joint y: +/- 180 degrees. Not really the way I want to do it.

I will add PD control to the joint which will want to change the sign of the velocity of the motor and so flipping the hinge joint orientation is not really an option for me.

Is this a limitation in the inspector or in bullet itself?

digitorus

I've figured this out. The problem is in the inspector: it does not allow you to enter velocity <= 0. I will log a bug on github.

You can set the motor velocity to positive or negative values in gdscript (not really clear from the docs)

hinge_joint.set_param(HingeJoint.PARAM_MOTOR_TARGET_VELOCITY,velocity)

Update: I have modified the godot source to fix the inspector problem, now allowing negative values. See Issue #19203 and associate PR (pull request) on godot github