Hey guys,
I need to animate chromatin, i.e. how DNA looks like inside the nucleus of non-dividing cell. The illustration for it is here: https://dl.dropboxusercontent.com/u/16530517/chromatin\_rig.jpg
So, it is not just DNA, but a complex of DNA with proteins that has a particular structure, which is still debatable (solenoid or zigzag form, etc.). Hence, I chose slightly modified “pebbles” paint fx brush, which suggests that complex undefined structure.
All molecules should be in constant Brownian motion, which I assigned on 2 different levels: turbulence on paint fx stroke, as well as a turbulence field on the curve; the curve was converted to a soft body (with the original as goal). Test-animation can be seen here: https://dl.dropboxusercontent.com/u/16530517/chromatin\_pebbles%202\_x264.mp4
If it were simply a “clump” that has to move randomly, my task would be finished.
However, there are “loops” of chromatin, where the actual transcription of mRNA takes place. These loops move non- randomly: they leave their “clump” (called chromosome territory) to loop out into the interchromatin space, where transcription enzymes are situated. Here lies the actual problem. If the curve was not so “clumpy” and complex, I could make joints, IK and cluster controls. As a matter of fact, I tried that, but it does not work nicely on this complex and highly looped curve.
Somehow I should be able to “pull out” the loop during the animation, but without stretching the curve (this makes paint fx stroke look stretched and “diluted”). So, I cannot just pull and keyframe single vertices. What else can I do?