I did not consider that yet, that sounds good. During the joint callbacks, I would only check the position and velocity of the joint, probably other sensors and then compute a new control output (apply impulse or similar). From what I read, the substeps are interpolations and therefore they are probably less precise than proper timesteps. The question really is if the substeps are interpolations, then the joint callbacks do not influence the movement if they apply impulses. Or do the interpolations consider that?Have you considered using joint callbacks for the controller? Basically at the start of the substep you can call back to whatever piece of code you want (hopefully nothing that adds or subtracts bodies or joints) in each substep. Basically you can keep steps the same size but you can choose what the size of the external step is based on your needs (for data logging, display, etc).
Where can I find the old DynamicControlDemo? From what I can see, there was no previous version (https://github.com/bulletphysics/bullet ... ontrolDemo).