Newsgroups: ont.events
From: mccool@dgp.toronto.edu (Michael McCool)
Subject: ACM Toronto Siggraph, Nov 17
Followup-To: mccool@dgp.utoronto.ca
Organization: ACM Toronto Siggraph
Distribution: ont
Date: 16 Nov 92 18:12:13 GMT

ACM Toronto Siggraph Event
==========================

When: Tuesday Nov 17, 8:00pm-10:00pm
Where: The McLaughlin Planetarium (just south of the ROM)
	   The Lecture Theatre (in the basement).
What:
	This event will be an expanded version of a talk that was presented
just this past week at the SMPTE (Society for Motion Pictures and
Television Engineers) International Conference.  It should be interesting
both to those interested in Dinosaurs, and to computer graphicists
interesting in seeing a detailed case study of a scientifically based
animation.  The synopsis presented at the SMPTE conference follows.

Title: Realistic Dinosaur Simulation

by Geoff Davidson, Glen Arendt, Robb Knock
Maniac Expressive, Brampton, Ontario

presented by Geoff Davidson.

Lurid and sensational depictions of dinosaurs in motion pictures and other
media has led to a persistent misconception of their natural history and
appearance, even among paleontologists.  Sprawling stances and lumbering
gates are common in these depictions.  However, enough fossil data and computer 
technology now exists to produce a highly *accurate* and realistic computer 
simulation of Tyrannosaurus Rex, a carnivorous dinosaur of the late 
Cretaceous period.

The simulation was produced using SoftImage and Cyberware software,
running on SGI platforms.  Accurate skeletal data from fossil specimens
of Tyrannosaurus were input into the model module of SoftImage to
produce the basis for a movement model.

An accurate one tenth scale physical model of Tyrannosaurus was reconstructed
using bone/tendon fossil evidence and modern homologues using comparative
vertabrate anatomy.  The model was digitized using Cyberware hardware/software
mounted on a custom large-scale, 5-axis robotics platform.  The range
data was converted to a polyline model and brought into SoftImage using
custom code and a Mediagram IGES translator.

Key paths for stride length were obtained from published studies of
tyrannosaurid trackways.  Joint rotation was modelled in SoftImage's Actor
module using published kinematic studies of therepods and modern
flightless birds.  Key paths for hip and joint location and timing were
made by rotoscoping ostrich movements from videotapes made at the Toronto
Metro Zoo.

Texture maps for the simulation were derived from scanned fossil dinosaur
integuments; colour corrected and distorted to compensate for stretch
when applied as UV texture maps.

The Tyrannosaurus model is constructed from 49 separate B-spline patch
surfaces, totalling 86,000 triangles.  The animation model consisted of 
7 separate articulated chains within the Actor module of SoftImage.  Six
separate forces were used to simulate the tail and gut motion.

The resulting animation portrays a trotting Tyrannosaurus with stiffly
held tail balancing the body mass and a medially overlapping (pigeon
toed), fully supported columnar stance.
-- 
=====================================================================
Michael McCool (mccool@dgp.toronto.edu or mccool@dgp.utoronto.ca)   
Dynamic Graphics Project, University of Toronto, Canada