 | | Object Orientation & DAT files & CLIPPING/WINDING
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There has been a great discussion, about the optimizing with clipping topic, but it seems IMHO that people are forgetting simplicity is the best. Now if you read the subject of this message, maybe you know what I am talking/writting about. we must (...) (25 years ago, 18-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) These are all assumptions/specifications which *should* be agreed upon by the L-CAD community, especially parts-authors and rendering program-writers. Agreement is only needed if we want to re-wire the parts library, to encourage (...) (25 years ago, 18-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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FIRST OF ALL my sugestion is that the CLIPPING, WINDING, INVERT are strictly local where they are used. CLIPPING is strictly local WINDING is strictly local INVERT is strictly local INVERT only means see referenced file as inverted. if INVERT is (...) (25 years ago, 18-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING [DAT]
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Steve Bliss wrote in message <380b3366.9260126@lu...et.com>... (...) No, you don't need to bother with the matrix. Use the 0 INVERT to tell the renderer: "Hey, please turn the following subfiles inside-out". Remember the example from stud2.dat: 1 16 (...) (25 years ago, 19-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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Rui Martins wrote in message ... (...) Part authors should define the tris/quad the way he finds best, easy and logical - maybe sometimes CW and sometimes CCW. Also when fixing old parts, just insert a lot of WINDING keywords in stead of editing the (...) (25 years ago, 19-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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Rui Martins wrote in message ... (...) I concur that WINDING is strictly local. It may be a struggle of words, but I wouldn't call INVERT *local* as it affects the behaviour all tris/quads in *subfiles* And I don't see why clipping should be local. (...) (25 years ago, 19-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) <snipped stuff about INVERT> I think we're disagreeing about the meaning of 'strictly local'. As you describe the operation of INVERT, it is *not* local. The state of inversion is passed down the file-reference tree. This is not a local (...) (25 years ago, 19-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) Yes the coded inversion is needed, for one big reason: The clipping-ready parts library must be compatible with non-clipping rendering programs, such as LDraw. So the inversions need to occur in the real commands, not in the clipping-extension (...) (25 years ago, 19-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) If by default you always use the same winding, then you can know the orientation of the polygon on the fly. IF you mix both you will have a hard time, because you are mixing or reference. (...) That I agree! but my NOTE (suggestion) to pair (...) (25 years ago, 20-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) Yes it is. (...) The reference of the current GLOBAL state is passed down the file-reference tree, YES. (...) Correct. (...) NOT the FILE, but the RENDERING PROGRAM ! (...) Agreed. (...) By default would be CCW. (...) YES and NO. The internal (...) (25 years ago, 20-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) Great! (...) It's local when you look at it in the .DAT where it is used. It's effect is NOT local, when you are looking from the renderer program's view, because it has to keep track of the current invert state. The INVERT meta-command only (...) (25 years ago, 20-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING [DAT]
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Steve Bliss wrote... (...) "Hey, (...) But it *is* compatible with LDraw! You left out my example (which BTW had the INVERT placed incorrectly :-), so I'll repeat it. stud2.dat is the hollow stud used on technic bricks. It uses two cylinders: 1 16 0 (...) (25 years ago, 20-Oct-99, to lugnet.cad.dev)
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| | Re: Object Orientation & DAT files & CLIPPING/WINDING
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(...) You are right. Or more precisely, I was wrong. Matrix-based *inversions* are not required. But matrix-based mirrorings will be necessary, for asymmetric primitives, like 1-4cyls.dat. (...) I was thinking about some approach that would map (...) (25 years ago, 21-Oct-99, to lugnet.cad.dev)
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