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From: work@forum.SUBLINK.ORG (Forum SuperUser)
Newsgroups: comp.graphics
Subject: Motion Blur in Ray Tracing
Keywords: Motion Blur Ray Tracing
Message-ID: <471@forum.SUBLINK.ORG>
Date: 23 Feb 91 10:25:51 GMT
Organization: Forum Graphics Exchange in Correggio (RE) ITALY
Lines: 29

I'm currently investigating ways to create motion blurred-ray traced images.
I have read most of the "Distributed" approaches to this problem and i found
the basic ideas explained very well (see An Intro To RT by Glassner & C.).

There is still, though, a thing that i miss: we have to sample objects
in different times of the same window and integrate the results, right?

BIG PROBLEM: how do you move objects while time-sampling? Should we store
several complete (huge) databases of objs at different times? Should we
transform objs every time we want to sample in time (very expensive!)?

From what i understand, storing several obj databases is too inaccurate
and could lead to time-aliasing (we just can't have 300 different slots into
the time window, since it would need 300 different obj databases).
But the other solution is almost suicide: perhaps suitable if we only use
linear transforms on obj for every single image. The famous "1984" from Pixar
showed a non-linear transform in one of the balls. If what we are rendering
is 4 balls, we can still move things around linearly or not, otherwise i think
the overhead involved kills the practical feasibility of this approach.

What i'm missing?

Andrea Gozzi.
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