 | | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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Portals. It's not backface culling, it's testing all polygons for visibility using possible rays through the openings, or from the sides of a bounding box. This is no longer culling based on front/back but true visibility that is computed once at (...) (22 years ago, 8-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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(...) OK, but if the quads and triangles don't form a single closed surface, or actually a bunch of closed surfaces, then the algorithm won't work. However, like I said, if you find something that works, post the code or the algorithm and you'll be (...) (22 years ago, 8-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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(...) Yes but I'm not parsing primitive subfiles in my plugin, just quads and triangles. -Orion (22 years ago, 8-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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(...) I love searching lugnet for neat old stuff... (URL) can't remember if any working code ever came out of this 3 year old thread, but this *is* a nifty sounding algorithm. If I were working on that plugin, I'd probably go back and read the (...) (22 years ago, 8-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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(...) I wouldn't bother. This well known algorithm is based on an assumption that simply isn't true for the parts files. The assumption is that there is one single enclosed space inside of each part. But I think the studs are open at one end and are (...) (22 years ago, 8-Aug-02, to lugnet.cad.dev)
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| | numbers report - 7 August 2002
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Stats for Unofficial Files 213 certified files. 222 files need admin review. 160 files need more votes. 241 have uncertified subfiles. 133 held files. 969 files total. For comparison: 2002-08-07 - 213 / 222 / 160 / 241 / 133 (969) 2002-07-16 - 131 / (...) (22 years ago, 7-Aug-02, to lugnet.cad.dev)
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| | Re: Beginner's tutorial to programming LDraw utilities (Delphi Edition)
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(...) Thanks! (...) There are lots of free resources for Delphi newbies on the net + a very good context sensitive online help. The description you requested is only a keystroke away (for those who have Delphi installed.) The Delphi help system is (...) (22 years ago, 7-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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(...) Thanks for the info, but it's easier written than applied. It'll take an entire revamp of my code. -Orion (22 years ago, 7-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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Error: read: Count how many *other* polygons this line segment intersects. for Count how many polygons this line segment intersects. Or, if counting your own polygon, switch even and odd. (22 years ago, 7-Aug-02, to lugnet.cad.dev)
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| | Re: Detemining Polygon Winding (Was: New Plugin for LDDesignPad)
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The simple algorithm: Project a normal from any vertex of the polygon to some point far beyond the object. Count how many polygons this line segment intersects. If odd, the normal was pointing in, if even, the normal was pointing out. This assumes (...) (22 years ago, 7-Aug-02, to lugnet.cad.dev)
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