Re: [Algorithms] Which subdivision schemes are used in products?

[Adrian B. <ad...@gm...>]

Beat to it.  Naughty Dog with the ps2 tech.  SSX has a presentation
out there somewhere (GDC?).  Most of these are tool time solutions or
very limited dynamic.

Insomniac has a fun paper about two bezier curve based surfaces:
http://insomniacgames.com/tech/articles/0807/curved_surfaces_on_the_rsx.php

I'm sure I saw a terrain paper which used some form of dynamic
tessellation, but it may not have been subdivision based.  Geometry
shaders will I'm sure increase the use of various forms of surfaces.
Nvidia has at least one demo using a subd technique.

Thanks,
Adrian

On Dec 14, 2007 10:08 AM, Bruce Woodard <bwo...@in...> wrote:
>
>
>
>
> For Warhawk, we used a very cheap but low quality (C0) vert & normal based
> SubD scheme developed in-house, running on the PS3's SPUs.  Our recursion
> depth was limited to two, and determined on a per-triangle-pair basis.
>
>
>
> We chose a vert & normal scheme to avoid any new authoring challenges,
> though our artists additionally had per-source-vert "puff" control for
> exaggeration or deflation to help stitching with adjacent non-subD objects.
>
>
>
> The C0 issues resulted in enough manual tesselation by our artists that in
> the future I would switch to explicit normal displacements computed using a
> better quality algorithm (still vert & normal based) and/or crafted offline.
> The data storage required for two levels of recursion is certainly
> acceptable.  In fact, our collision representation actually did use explicit
> displacements for performance reasons.
>
>
>
> ---bruce
>
>
>
> PS - I believe SSX for PS2 (can't speak to the sequels or other platform
> implementations) used Bezier patches.
>
>
>
>
>
>  ________________________________
>
>
> From: gda...@li...
> [mailto:gda...@li...] On Behalf Of Eric
> Haines
>  Sent: Wednesday, December 12, 2007 10:01 AM
>
>  To: Game Development Algorithms
>  Subject: [Algorithms] Which subdivision schemes are used in products?
>
>
>
>
>
> We're writing a new edition of Real-Time Rendering. One question came up:
> what subdivision schemes actually see use in products, either shipping or in
> production? Catmull-Clark is used by Valve and others. But beyond that I
> personally don't have a sense of what's actually implemented. N-patches for
> the Xbox 360? Any of the other subdivision schemes? Or other curved surface
> types, e.g. NURBS?
>
>  In one way this is a peculiar question: "whatever the modeler provides us"
> is the answer. What I guess I'm more interested is whether higher order
> surfaces get used in games on any platforms for things like tessellation on
> the fly for LOD, CLOD, for compact storage, etc.
>
>  Any data points appreciated,
>
>  Eric
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