I’m entering the world of animation from the world of math and physics, and, as I see things, a knee is a basis of the walk. I have learned in the Cut-out Animation Tutorial how to make a knee: I fix the hips and vary two angles. But where will my foot end up? That’s not the way I want to walk. I want to set the foot position, and let Synfig calculate the angles. See here what I mean: youtube.com/watch?v=igCxjvWv8X4 . So I did this, and it was way too much math (for this mathematician), especially because there is no root or power function so I had to compute the root trough the exp and log functions (which make the left-right jump in the video I think), and there is no acos function so I had to get it from atan2 function… And the whole thing with parameters conversion is so cumbersome for any real math - some scripting would be so cool… But the biggest problem is that I don’t know how to reuse this work. I spent an evening making this one leg, now what if I want to animate a spider? Do I have to do everything from stretch for each leg, or is there any way to copy the whole parameters tree and change it’s input, i.e. connect it to different points, to make it work on another leg?