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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 (...) (22 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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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 (...) (22 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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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 (...) (22 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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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 (...) (22 years ago, 10-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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(...) I like the idea of CSG. Unfortunately I can not invest time in Rayshade and alternate ray-tracers. I know they can have attractive features but I am more a POV user. I must impose some limit to my (already too high) diversification. Of course, (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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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 (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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(...) Sorry, I must have been reading more into your example than you intended. (...) It's the former: the author intends to make a reflected object, but not an inverted object. (...) It depends on who (or what) you want to keep things simple *for*. (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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If you're interested, take a look at my old Rayshade libraries that made the bricks from scratch using CSG. I'm especially fond of the L3G0 40-tooth technic gear. I've thought it would be nice to have "bounding boxes" for the bricks, for collision (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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Maybe I'm more confused now, or less who knows. But I don't think I made what I was trying to say clear in that last post. So here I am replying to myself... :) (...) That last sentance doesn't really get across what I was trying to say I think. (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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Steve Bliss wrote: > In lugnet.cad.dev.org.ldraw, Kyle McDonald wrote: > [snip more] > > You understand the usage correctly. Except there's no special tie > between a 'mirroring' subfile reference and the INVERTNEXT command. > Authors won't (...) (22 years ago, 9-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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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) (...) (22 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: request for modification (Tracker)
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(...) Wow. Good ideas. Unfortunately, for now, I'll have to file them in with all the other improvements I want to make on PT. There are a few key changes that need to occur before many other things can happen. Steve (22 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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(...) That's weird - I know I answered your email. No big deal. (...) files already having been done by you and Damien), you're going to work on the rest of the boxes. Anyone else want to help? (...) You *can't* post new versions of official files. (...) (22 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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(...) [snip] OK, sounds reasonable to me. (...) Yes. (...) [snip more] You understand the usage correctly. Except there's no special tie between a 'mirroring' subfile reference and the INVERTNEXT command. Authors won't explicitly use one to 'undo' (...) (22 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Numbers Report
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In lugnet.cad.dev.org.ldraw, Damien Guichard wrote: [snipped a lot of great comments about using different pages on the PT] I totally agree with everything Damien wrote, except that if one only pays attention to the Activity page, older files may (...) (22 years ago, 8-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Numbers Report
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(...) I think Bernd and Sascha are brothers. Part authors keep LDraw alive. Steve B. has a quite expeditive (if not bureaucratic) response to your legitimate expectings. My advise is: visit the "activity" PT page rather than the "certication" or (...) (22 years ago, 7-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: Parts as volumes (instead of surfaces)
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[ XFUT lugnet.cad.dev ] (...) What's "CSG descriptions"? (...) But they aren't (as you also write). Still, you are probably correct that BFC information in the LDraw parts can be used for collision detection. (...) I think it deserves further (...) (22 years ago, 7-Apr-02, to lugnet.cad.dev.org.ldraw, lugnet.cad.dev)
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| | Parts as volumes (instead of surfaces)
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It has been said that, with ldraw parts, we have the geometry of TLG bricks. This is rather optimistic. Because geometry would be CSG descriptions that allow much more (although slower) than quads and triangles. CSG descriptions allow part collision (...) (22 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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Hello, Comments below... Travis Cobbs wrote: > In lugnet.cad.dev.org.ldraw, Steve Bliss writes: > >>In lugnet.cad.dev.org.ldraw, Tony Hafner writes: >> >>>In lugnet.cad.dev.org.ldraw, Steve Bliss writes: >>> >>>>>Um... Not to stir the pot or (...) (22 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)
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| | Re: [Parts Tracker] More BFC Primitives
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(...) Given the fact that they have to check whether or not a given file has been mirrored, I can't see that the directionality would make a large difference. If everything used CCW, then only mirrored ones would need to be reordered (assuming the (...) (22 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)
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