On Jul 15, 2010, at 2:33 AM, Joshua Leung wrote > On Thu, Jul 15, 2010 at 7:46 AM, David <erwi...@gmx.net> wrote: >> Hi all, >> >> After playing around with the curve modifiers, I wanted to request a >> feature: a f-curve modifier that evaluates another f-curve to >> determine its function, but this seems so obvious that I must be >> missing something. It could be hard to implement, or, is it already >> possible to do this differently (I would expect it to be somehow >> doable with the python modifier)? >> >> > Hi, > > Could you explain why you want such functionality? What is it that you're > trying to achieve, and why are any existing methods not adequate to do so?
Sure, in my (rather technical) use case I want to animate a camshaft that triggers a couple of valves. I have the amplitude that the valves travel given as a function of the rotation of the camshaft (360 values). My idea was to put this data in some f-curve on an empty, and give each valve a driver that takes the rotation of the camshaft as a variable and has a modifier that would look up the correct amplitude in the empty's f-curve. This would allow me to easily animate the rotation of the camshaft and have all the valves automatically behave correctly. Also, I felt this would be a very natural approach to the problem. > I just want to verify that this is something that is really necessary, and > not just something that would be "nice to have" for bragging rights, etc. :) I have to say it is not strictly necessary, because I managed to get my desired effect almost as described, but instead of using a modifier, the lookup is simply done in a "scripted expression" that looks like this: bpy.data.actions.get('cold_valve').fcurves[0].evaluate(degrees(var)%360) (where 'var' is the rotation of the camshaft) Obviously this is not as nice as a separate modifier, but I would already be very satisfied if there was an easier way to get to the f-curve in the python script (maybe there is and I don't know it yet?). till then, David. _______________________________________________ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers