 | | Re: Parts as volumes (instead of surfaces) —Steve Bliss
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| | | (...) Wow, good questions. We know that some collision detection is already practical - Eric Olsen demonstrated that over a year ago. But decomposing LDraw parts into convex objects, that would be a trick. Each external box 5 (or pair of box 5's) (...) (23 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | Re: Parts as volumes (instead of surfaces) —Damien Guichard
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| | | | (...) Stud4 primitive could be convex-decomposed just as Ring4 primitive is today. More generally, just as any LDraw surface is convex-decomposed with just triangles and quads (3,4 points respectively), I guess any LDraw volume can be (...) (23 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | | Re: Parts as volumes (instead of surfaces) —Steve Bliss
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| | | | (...) So stud4 would be decomposed into 16 trapezoidal prisms? That sounds like a fair amount of mark up. (...) Nod, true. But I'd rather decompose a 1x1 brick into 6 volumes (4 walls, 1 top and the stud) than 46 (one volume for each surface (...) (23 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | | Re: Parts as volumes (instead of surfaces) —Erik Olson
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| | | | | (...) That was only bounding boxes (minus the studs). The piece in question was matched against all other pieces, any pieces in a line above or below were put into a list. In case one of them intersected the piece in question, a new place would be (...) (23 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | | Re: Parts as volumes (instead of surfaces) —Damien Guichard
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| | | | (...) Well, I can have a twisted mind sometimes. I know these moments when the best idea today, will just be plain stupid tomorrow. Thanks to Eric Olson for more precision: he used bounding boxes, not collisions. Also I still think, whereas higher (...) (23 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | | Re: Parts as volumes (instead of surfaces) —Steve Bliss
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| | | | (...) Maybe I'm missing a technical distinction, but it seems he used bounding boxes *for* collision detection, as opposed to using exact volumes. (...) True. My point was, marking up the LDraw part files for volume decomposition would either: a) Be (...) (23 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | | | | | Re: Parts as volumes (instead of surfaces) —Erik Olson
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| | | | (...) "marking up" would be better done by machine algorithm, and would encompass the Connection Point proposal at the same time. It would indeed yield a separate definition of the parts. A lot of high-end CAD programs read polygons (like we have) (...) (23 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
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