Beta Post

So, we just had our beta-review. It was very informative.

To start, here are links to two videos which we showed to Norm and Joe at the review:

Beta-Spline Creation/Manipulation in Maya:
http://www.youtube.com/watch?v=cqRP3GKNFoA
 This video shows a UI that Omar created in Maya with MEL. It takes in control points and outputs a beta-spline. The spline can be interactively manipulated with the bias and tension sliders.

Drawing Joint Translation Curve in Maya:
http://www.youtube.com/watch?v=2aq11vV5tqc
This video shows the result of a Python script that draws a single joint's translation over time in Maya. There is a discontinuity at the end of the curve, and we think we figured out why. At the moment, the curve is drawing the position of the joint at each frame. After frame 130 or so, the joint quits moving. This causes the same point to be passed in many times, which creates a discontinuity in the curve. Nicole thinks an easy fix would be to check when the first and last keyframes are set for each joint, then "cut" that section from the position list. Which leads to a question: Does anyone know the Python command to query if there is a keyframe at a certain frame?

What we learned:

One of our main issues that we came across is that we are using two different types of curves. Maya uses NURBS curves, whereas Omar is using beta-splines. Since Maya provides no way for us to define curve interpolation any differently, we need to export NURBS curve data to beta-spline control point data.

Since our animation curves generate such a large number of control points, Joe and Norm suggested that we export the NURBS control points in Maya at a uniform timestep of our choosing, producing somewhere between 10 and 25 control points (this range may change if we find we need more of them). These control points will then be passed to Omar's beta-spline creator, which will generate a beta-spline to be manipulated. After manipulation, we will determine the new set of points on the curve and pass them back to Maya to then be used as the new animation curve.

The first part--taking the 200-something control points from the NURBS curve and outputting a list of control points for a beta-spline--will be a pre-processing step. We are treating the base animations that Nicole created as an animated gesture database. Since they should not change (theoretically), then we can also store lists of control points that correspond to each gesture in a similar database.

Now, we're feeling pretty confident that we can get our parts working together and working well. Hopefully, we'll have some good progress to show by Thursday's post!

Until then.

From Russia with Love,

Nelskati