3D Animation and Maya

Although I'm not a world class 3d animation expert, the artist member of our little team was. His name is John Yoon, and he's an amazing guy. He went to MIT with Ken and received a degree in computer science, then worked for a number of years at Alias/Wavefront as an engineer on Maya. Later he went to UCLA, received a masters of fine arts, and subsequently worked as a technical director at Disney and Dreamworks on animated feature films.

Thanks to John's expertise both in using Maya and with its internals, and his ability to educate us, Ken and I were able to build a pretty impressive content pipeline from Maya to our system in a pretty short amount of time (about a month). Sven Goethel helped out and did the normal maps.

I wrote a Collada importer for an earlier version of our system, and John joined the Collada working group to see if we could move it forward, Our joint conclusion was that Collada is essentially dead. Autodesk FBX as a de-facto standard has prevailed. Although, it was our intention to also support FBX at some point, for the first go-around, we decided to support importing Maya ascii format files directly.

Maya is a huge and very impressive system. We worked incrementally out of necessity. Our first test case was a red spinning cube. John guided us along, creating incrementally more sophisticated test cases, deciphering the semantics of maya nodes for us, and helping with the math on our side.

Ken did the majority of the work and did an amazing job.

We translate Maya key frame animation into JavaFX script timelines. Ken wrote interpolators for Maya's tangent-based animation curves.

In general we translate [a subset of] Maya's dependency graph into a corresponding JavaFX script dependency graph. We're able to import lights, cameras, blinn-, lambert-, and phong- shaders, normal maps, light maps, point-, parent-, aim-, and orient- constraints, skin clusters, blend shapes, 2-bone ik, radial fields, motion paths, nurbs curves, triangle meshes, point emitters, particles, transform nodes, rigid bodies and rigid constraints, and utility nodes including math and logic

Here's a list of the Maya nodes we support in whole or part.

• mesh
• transform
• bump2d
• lambert
• reflect
• blinn
• phong
• file
• animCurve
• animCurveTA
• animCurveUA
• animCurveUL
• animCurveUT
• animCurveUU
• materialInfo
• skinCluster
• blendShape
• joint
• ikHandle
• ikEffector
• poleVector
• rigidConstraint
• pointConstraint
• aimConstraint
• constraint
• parentConstraint
• orientConstraint
• pointEmitter
• radialField
• particle
• unitConversion
• multiplyDivide
• plusMinusAverage
• condition
• reverse
• choice
• layeredTexture
• uvChooser
• place2dTexture
• clamp
• blend
• blendColors
• blendWeighted
• light
• pointLight
• spotLight
• directionalLight
• groupParts
• polyPrimitive
• polyCube
• polyCylinder
• polySphere
• motionPath
• nurbsCurve
• addDoubleLinear

Using animated 3d models in our system is quite easy, for example:

var model = Model {
url: "models/red-spinning-cube.ma";
};

model.play();

Animated models are Nodes which are also polymorphic with Timelines. You can play them, pause them, rewind them etc. The Model object also exports various named resources to the script, such as cameras, lights, shaders, meshes, transform nodes, etc. Thus after loading a model it's possible for the script to modify or replace elements, or parent script created nodes to imported ones. For example, the model could be created with a placeholder texture used by a shader. Upon loading the model the script could lookup the shader and replace the placeholder texture with, for example, a dynamically loaded movie. Anthony has a picture of this use case on his blog