Home

 

Teapot Modeling

 

Vertex Detection

 

Cell Division

 

Blobbies

 

L-Systems

 

Particle Baking

 

Expression Driven Animation

 

Staircase Generator

 

Independent Study

 

Cell Division


This page provides a technical breakdown for an animation of a cell undergoing cell division (cytokinesis).


This video shows my final cell division effect. By using Renderman blobbies, the illusion of creating two cells from one was pretty simple to achieve with a few mouse clicks so I decided to create a nucleus too. I'm pretty happy with the way my shaders achieved the microscopic look.

Reference Footage






The two reference videos on the left were taken from Interactive Eye. The footage on the right was taken from the University of Washington.

Renderman Blobbies







The animation to the left shows a playblast of my final animation as seen in Maya's viewport. Unfortunately, using Renderman blobbies requires certain sacrifices. 1) The cytokinesis effect can only be seen during render time so it's harder to keyframe exactly when the cells would split away from each other. 2) Blobbies don't have UV or ST coordinates so texturing must be procedural. 3) The blobbies have no shape nodes or vertices to manipulate so deformations are pretty limited. As a result, I grouped the blobbies to themselves so that I could at least fake a squash and stretch effect by keying the scale attributes of the new groups. If I didn't create new groups, the result would look more like the animation on the right.

NURBS Spheres


By creating a fillet connect by two isoparms of neighboring spheres, the effect to the left was created. Although it was close to the end result that I wanted, the elasticity was too great and the geometry can be seen within each other's interiors. As you can see in the reference footage, dividing cells don't stray too far away from each other during cytokinesis. To force a closer subdivision, I needed to use multiple pieces of geometry and key their visibility at the correct times.

This video shows a playblast of Maya's viewport for my NURBS animation. The effect appears to be exactly what I wanted, but unfortunately shading becomes a problem at rendering time.



This video shows the results of my attempt at using NURBS for the cell division. There's slight "popping" of the texture because I keyed the visibility of elements to swap out geometry. Unfortunately the method I used relies significantly on keyframing and animation techniques so multiple cell generation would be difficult with this method. Details on how I created this effect can be found below.

The MEL script is available here.

This image shows the parts I used to create the NURBS division effect. Each sphere was divided into three parts and two fillets were used to create a smoother pinching transition while keeping the cells close together. Unfortunately the use of several parts causes the texture popping as seen above. A solution would be to force all the geometry to use the same coordinate system, but unfortunately, it didn't work for some reason. Another solution would be to render the cells without any fancy displacement or texturing but that would be pretty boring and of limited use.

 

Richard Sun / Rich Sun Productions 2007.