Monthly Archives: November 2013

Time Reverse Technique Cont

Another example of the reverse animation technique. An advantage of building the animation starting with the end stage model, is in placing the fibrin strands. The strands look like they are forming around the clot of red blood cells and activated platelets. This was accomplished by uv mapping the strands, and then animating texture maps to revel the strand models. Because we are using reverse animation, the end stage model is a known shape, and the strand models can then be created around the layers of the end stage model, without intersecting the RBCs and platelet models.

Time Reverse Technique

This complex time lapse animation of plaque building up was a challenge to create.

The reverse animation technique was very handy here. Baking and then time reversing simulations and particle effects can look like a building up effect. In this case, the finished or end stage plaque was built first and then slowly eroded away.

Static models of Rbcs and platelets were placed in the scene and then turned into particle instances using a script like this one.
vmvInstanceObjects 1.0.2 (maya script)

Next a gravity field and other particle fields were animated thru the static array of blood cell model instances… Peeling away the rbcs and platelets starting from the outside moving inwards and making them float upstream and away.

When the simulation was looking good, the particle instancers were converted back to individual 3d models with baked keyframes for position and rotation. There are many plug-ins and a few scripts available to bake the simulation. I prefer using a script like the one in the link below versus plug-ins. Plug-ins need to be recompiled with each new maya version, and scripts do not.
tk_bakeParticleInstancer 1.4.0 (maya script)