Subject:
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Re: BFC and Primitives
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Newsgroups:
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lugnet.cad.dev.org.ldraw
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Date:
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Fri, 8 Mar 2002 00:22:55 GMT
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Viewed:
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518 times
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Also, I believe, that no matter whether you use Back Face Culling or
not, Having the vertices wound correctly in the DAT files is still
a good thing. In the absence of a standard winding, then Documenting
in each part the way the polygons are wound is the next best thing.
I'd have to imagine that even with this new BSP traversal method,
you still really need to know how the vertices are wound if you are
to compute the vertex normals corectly. And you need the vertex normals
if you are going to do lighting and other effects. Right?
-Kyle
Damien Guichard wrote:
> I quote Michael Lachmann, from MLCad file ReleaseNotes.txt:
>
> Beginning with release V2.00 MLCad does no longer support BFC.
> However the metacommand itself is still supported but has no effect on
> drawing (BFC - BackFaceCulling was an experiment on improving the rendering
> speed, MLCad release V2.00 and above is using another methode, which
> improves the speed much more than BFC could ever do)
>
> End of quote.
>
> Your program benefits BFC just because you use back to front BSP tree
> traversal. I guess MLCad 2.0+ uses front to back BSP tree traversal, and
> scanline hidden surface removal.
> For more info about scanline hidden surface removal, see BSP tree faq:
>
> http://reality.sgi.com/bspfaq/whole.shtml
>
> Question #9 is "HOW DO YOU REMOVE HIDDEN SURFACES WITH A BSP TREE?" and
> explains front to back BSP tree traversal and scanline hidden surface removal.
>
> I hope it helps,
>
> Damien
--
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-------------------------------ooO( )Ooo-------------------------------
Kyle J. McDonald (o o)
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\\\//
(o o) kmcdonald@BigFoot.COM
-------------------------------ooO(_)Ooo-------------------------------
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Message has 1 Reply:
 | | Re: BFC and Primitives
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| (...) You have to calculate a vertex normal in order to do lighting. However, it doesn't have to be the correct normal if your rendering engine supports 2-sided lighting (like OpenGL does). In this case, calculating a normal that points backwards (...) (23 years ago, 8-Mar-02, to lugnet.cad.dev.org.ldraw)
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Message is in Reply To:
| | Re: BFC and Primitives
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| I quote Michael Lachmann, from MLCad file ReleaseNotes.txt: Beginning with release V2.00 MLCad does no longer support BFC. However the metacommand itself is still supported but has no effect on drawing (BFC - BackFaceCulling was an experiment on (...) (23 years ago, 7-Mar-02, to lugnet.cad.dev.org.ldraw)
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