Re: Plug for CSG
Vassilis Bourdakis ([email protected])
Fri, 16 Jun 1995 19:52:40 +0000
>On Jun 16, 10:29, Jeff Sonstein wrote:
>> Subject: Plug for CSG
>
>[etc., etc.]
>
>> CSG make
it easy to express virtual things the way people think
>> real things...
>
>[etc., etc.]
>
>I think
>CSG is good for modeling.
>So... write a *modeler* which use
CSG for its user interface.
>CSG *can* also be compact, but doesn't have to be.
>Just try to model something organic for instance.
>Say an egg, or s muman, or terrain.
>Quite easy to do with an IndexedFaceSet or NurbsCurve...
>Even your gear example, for a realistic gear with notched teeth and
>fillets around a reinforced bearing surface,
>a CSG format.
>
>However, CSG is *la>
y* for rendering.
>So...store and render using surfaces (like VRML), but
>MODEL HOWEVER IT BEST SUITS YOU, even with CSG!
>This is, I believe, what all major modeling/CAD packages that
>support CSG do.
>
>These issues are addressed in Foley, van Dam, Feiner, Hughes,
>"Computer Graphics Principles and Practice".
>
>Conclusion:
>
>This is not something which should be put in VRML, since VRML
>is a geometry description, not a modeler or modeling tool
>Enough
>
>
>Tim.
>
Couldn't agree more Tim!!!
Let's not forget what the VRML aim is - or st least what I think
If CSG is effective in storing stuff and awful in rendering them, I'd have
the big files
An Example I did in ACADR13 last week and translated today
as a CSG design
2MB in 3DS 9MB in ascii DXF and ended up as 3.3MB in IV and down to 2.5MB
in WRL! The CSG description was surely efficient in acad but rendering
these complicated forms was a pain...
Vassilis