Ok, I was mixing two things up -- the orignal CCD work of Stephane's, about which I know a little, plus this:
about which I don't actually know too much, but from the pictures it sure makes it look like CCD with capsules.
Erwin, when you refer to "Redon's ccd" are you including the above work as well?


On 11/4/05, gdalgo@erwincoumans.com <gdalgo@erwincoumans.com > wrote:

Stephane Redon's ccd is feature based, so no swept capsules there.

You can use another ccd approach based on an extension of raycasting the
Minkowski sum. See Gino van den Bergens paper on this topic:

Both this and Redon's method are implemented in my Bullet continuous
collision detection library. It includes pure linear (swept) and angular
motion too. Supported shapes are triangle,
sphere,box,triangle,capsule,cylinder,cone etc.


Erwin Coumans

Bill Baxter writes:

> Have you looked at Stephane Redon's work on continuous collision detection?
> I'm pretty sure he does swept capsules. He makes it tractable by assuming a
> particular form for the rotation between frames, namely an exponential map.
> So it's not using the "correct" rotation to represent the inter-frame
> motion, but that's not such a big deal because without actually running your
> simulator at finer timesteps you have no way of knowing what the correct
> motion is anyway. In the end it comes out to be solutions of fairly
> low-order polynomials. And I think he does some interval math / Sturm
> sequence type things to avoid actually having to find the roots.
> Anyway, his stuff is worth a look if you haven't seen it already.
> --bb
> On 11/4/05, Jeremiah Zanin <jeremiahz@volition-inc.com > wrote:
>> Swept capsule vs. triangle is pretty tricky and I haven't seen it
>> documented
>> anywhere. I implemented it by breaking down the problem into smaller
>> problems (line segment vs plane, sphere vs plane, circle vs line segment,
>> sphere vs line segment, sphere vs point). I'm not sure how to do a swept
>> capsule that accounts for rotation other than relying on detecting the
>> collision due to penetration. I'm wondering how many games actually use a
>> swept capsule instead of a series of spheres...
>> >
>> > Usually, this (character collision i mean) is done by doing a swept (in
>> > time, not space) capsule vs triangles test - but this is difficult to
>> get
>> > right; there are a lot of cases to deal with. Especially if your capsule
>> > is rotating.
>> > ...
>> > Cheers, Paul.