The trajectories of the corners of the piston then generate the required contour of the combustion chamber (the exact contour in this case, but an offset for a sealing lip would also be possible).
The model is suitably constrained and uses points as handles (highlighted in red) to adjust the eccentricity, the size of the piston and the curvature of its surfaces, either by moving handles with the mouse or by entering values directly. Different motion profiles can easily be activated by switching connections in the drive control. If, instead of at just one corner, the trajectories are visualized at all three corners of the piston, you can see that all three trajectories are always identical due to suitable constraints that have been placed on of the piston (or rather: on the entire system).
