CPSC 526 Class Wiki

Test post for paper discussion.

-- MichielVanDePanne - 04 Nov 2011

Contribution:

Virtual characters are represented as directed graphs having nodes and connection. A genetic language based evolution of motor as well as neural control is suggested. No user information regarding shape/size, joint constraints etc are assumed when developing the creatures.

Computation of results:

Since the entire task is computationally expensive, parallel implementation of the task is done. Evolutions of about 50 to 100 generations i.e. by mating directed graphs either by crossover operation (30%) or by grafting(30%) and sometimes asexually (only using mutations) (40%), are performed corresponding to four types of behavior, i.e. swimming, jumping, walking and following. Another suggested method was to interactively evolve a morphology so as the creatures have aesthetic touch to them instead of just goal based evolution. Hybrid world creatures were also developed.

Reproducibility:

My view is that the paper is reproducible. Although models are not detailed mathematically, they make up for it by giving exhaustive description of the same. The models used for sensors, nerons and Effectors are detailed properly in section 3. Details about the use of physical simulation techniques e.g Feather's method to calculate accelerations, Runge-Kutta fehlberg method for integration and other details for virtual world simulation (e.g water, collison etc) are provided in section 4. The genetic optimization based behavior selection method is also well explained in section 5.

Improvements in Research/Writing:

Overall the paper is well written but I would have preferred some more light to be thrown on the technical aspects of the overall model and specially the modeling of characters as directed graphs and the genetic evolution process.

-- Main.sumanm - 17 Nov 2011

Above is the review of : "Evolving Virtual Creatures"

-- Main.sumanm - 17 Nov 2011

Review : "Practical Character Physics for Animators" Contribution: - Interactive system to enhance character motions, by incorporating physical properties into a existing key frame system. - Tools to enhance realism of balistic motions. - Investigate physical accuracy of manually created animation by skilled animators.

Result Evaluation:

1. Ballistic Paths : The path is created based upon the center of mass m and a constraint. The animator has 2 ways to incorporate this into the animation, either by adjusting the timing of the motion, freezing the initial and final positions or manualy adjust the path and then retime the entire motion.

2. Angular Momentum: An iterative approximation algorithm is suggested to compute the configuration (T_o) of the character given the momentum (h) specified by the user. THe method makes use of the rigid body inertia (J), velocity (v_i), the position (x)

Reproducibility:

The paper should be reproducible to a considerable extent. All the techniques used are backed up with corresponding pseudo code/step-by-step algorithm. The variables are clearly explained in both the cases of ballistic path and angular momentum. An appendix explaining the background on the equations governing the physical properties of an animation is also provided for assistance.

-- Main.sumanm - 17 Nov 2011