Perhaps someone knows how to do this...I want to motion track a moving object in a clip and then apply the track data to a null object. NEXT, I want to link a paint brush to the null object so that it paints a continuous stroke that matches the movement of the tracked point. I have managed to create a single frame paint "dot" and then link the dot's position to the null - it moves along fine but doesn't paint a continuous line. Some how I need to account for a regular paint stroke requiring the mouse button be held down. Thanks
Use a particle generator. Make the emitter be the point. Turn the birth rate up high so it looks like a continous line. Modify the life time to the length that you need it to be. Turn off gravity and maybe mess around with the other physics.
you can set the paint brush settings to 'write-on', but i'm not sure you could link it to your tracking null.
you could try the write-on effect, enable expressions for the brush position property and use the expression pickwhip and drag it to the null's position property to link them together. then the write-on brush should follow your track.