Project 1: Animation System Assigned: 01/17/06 Due: 01/31/06

Project description Hierarchical modeling  Use OpenGL code to build a model of your own design Keyframe animation system  Implement three types splines to animate your model

Skeleton code Modeler View vs. Curves View Graph Widget Interface How to integrate with my model?  just add replace robotarm.cpp with your model  build a simple testing model first just to see if it works

Requirements Bezier curve  Splice Bezier curves together with C0 continuity B-spline Catmull-Rom splines C2-interpolating splines (optional)

Where should I put things? For each type of splines, create a subclass that inherits from CurveEvaluator  Bezier  B-spline  Catmull-Rom Implement virtual function evaluateCurve() for each subclass In GraphWidget class  Change the skeleton to call your new constructors in the GraphWidget class.

Extra Credit ideas Tension control for Catmull-Rom  D n = 1/2(C n+1 – C n-1 ) Allow control points to have C 0, C 1, or C 2 continuity  This can be VERY helpful in creating a good animation

Extra Credit ideas “ wrapping ” the animation  You can implement “ wrapping ” feature to ensure C0 continuity between the end and the beginning of the animation Add more control points without changing the curve  This feature is important when you want to refine your animation in a localize region

Extra Credit ideas Adaptive Bezier curves  Use divide-and-conquer algorithm to display the Bezier curves, rather than sampling at some arbitrary interval  Use GUI to visualize the change of parameters Implement a C2-interpolating curve  There is already an entry in the drop-down menu  Allow the user to specify the derivatives of the two endpoints of your C2-interpolating curve

Extra Credit ideas Procedural modeling  Use procedural algorithm (such as L-systems) to generate all or part of your model Refine Catmull-Rom splines  Use the two “ inner ” Bezier control points as the handles of Catmull-Rom splines  Provide GUI to manipulate the control points and the handles

Extra Credit ideas Selecting body parts  Implement GUI so that you can click on part of your model to select its animation curve Speed control  Implement “ ease-in-ease-out ” principle by manipulating the speed control curve Adding more features to the UI  If there ’ s anything you don ’ t like about the UI, change it!

Extra Credit ideas Talk to me first if you want to implement these features  Quaternion rotation  Motion wapring  Subdivision surfaces

Animating well vs. well … just animating Timing!  Timing is VERY, VERY important  Consider timing before you bother to get specific about joint rotations or object positions

Animating well vs. well … just animating Good timing

Animating well Music!  Sound and music can greatly enhance the cohesion of your artifact  If your artifact idea includes a theme or stylization, it can be very effective to time your animation with events in the theme music. Good sound

Animating well Light!  Like sound, light is VERY VERY important compositionally  Anything you can do to be creative with lighting will help Light vs. No light

Creating Your Artifact Choice of curve types  I recommend Bezier curves. Why? Recall the animation of a bouncing ball When the ball hits the ground, the curve describing its position should have a C 1 discontinuity Without C 1 discontinuity here, the animation will look wrong  Catmull-Rom is usually the preferred curve choice … but unless your project supports the option to add C 1 discontinuity at will, you might find yourself trying to fight the Catmull-Rom to create pauses and other timing goodies

Creating Your Artifact Compositing  Recommended that you break your intended artifact up into shorter clips combining them all in the end.  This will make your life easier for many reasons: Splitting up work is straightforward Changing camera angles is GOOD for a composition You can incrementally complete your artifact  Download a trial of Adobe Premiere Play around with it, check the website for some details on how to use it. The user interface is pretty intuitive.

Any Questions?