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 CAD / Development / Organizations / LDraw / *1941 (-20)
  Re: Implicit face winding (was: [Parts Tracker] More BFC Primitives)
 
Tony Hafner wrote: > In lugnet.cad.dev.org.ldraw, Kyle McDonald writes: >> >>Well I don't know that I thought it would be 'minimal' effort. I'll >>bet it would be a lot of work for parts that are already done. I >>did think that it wouldn't be that (...) (22 years ago, 12-Apr-02, to lugnet.cad.dev.org.ldraw)
 
  Implicit face winding (was: [Parts Tracker] More BFC Primitives)
 
(...) I recently went over some old primitives and brought them up to BFC certification. I found it very handy to have the flexibility of doing it whichever way had more "correct" surfaces. It wouldn't be so bad if Notepad had the ability to reverse (...) (22 years ago, 12-Apr-02, to lugnet.cad.dev.org.ldraw)
 
  Re: [Parts Tracker] More BFC Primitives
 
Hi Travis, (...) Well I don't know that I thought it would be 'minimal' effort. I'll bet it would be a lot of work for parts that are already done. I did think that it wouldn't be that bad for new parts, because I figured the author knows best what (...) (22 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
 
  Re: [Parts Tracker] More BFC Primitives
 
(...) Despite being the author of a rendering program, I agree with this whole-heartedly. Each rendering program only has to get it right once, during the initial coding. If we make it easier for the program, but harder for part authors, the part (...) (22 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) "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) (...) (22 years ago, 11-Apr-02, to lugnet.cad.dev.org.ldraw)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: [Parts Tracker] More BFC Primitives
 
(...) 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)
 
  Re: Parts as volumes (instead of surfaces)
 
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)
 
  Re: [Parts Tracker] More BFC Primitives
 
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)
 
  Re: [Parts Tracker] More BFC Primitives
 
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)
 
  Re: Parts as volumes (instead of surfaces)
 
(...) 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)
 
  Re: request for modification (Tracker)
 
(...) 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)
 
  Re: [Parts Tracker] More BFC Primitives
 
(...) 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)
 
  Re: [Parts Tracker] More BFC Primitives
 
(...) [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)
 
  Re: Numbers Report
 
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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