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 CAD / LDraw Files / Parts / 6100
  Re: Part Authors: opinions sought on T-Junctions
 
(...) I'd really appreciate it if you didn't blame it on the rendering programs. There's really nothing that they can do to fix the problem. I can understand why you might feel that they are at fault, but it really isn't true. As such, you might (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) Arguably it's probably the algorithms and/or numerical proccessing that are at fault. Certainly when you design scientific code algorithms they should usually be created in such a way that it minimises numerical error. Of course I don't expect (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) Well... Technically it is true. The rendering program ought to be able to scan all the points in each part and look for intersections with every edge in the part. Then break up the offensive T-joins automagically and render it perfectly. (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) OK, I stand corrected. Technically a program can fix things a load time. However, you might be surprised at how long it takes. It's "only" O(n^2), but each iteration is slow. You have to search the current line segment against all other line (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) Well actually what txt2dat does is a slightly different problem - it has a few simple closed loops and has to triangulate the complex polygons bounded by them (it uses the excellent (URL) triangle library> to do that). Renderers on the other (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) There is, however, such a thing as an impractical problem ;) ROSCO (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) blah, blah, blah, snip Oops, I was trying to be all ironical in a geeky math sorta way. But apparently I failed. Guess I shoulda used more winkies... Do people still use winkies? Or have they gone obsolete like ASCII art? Anyhow, sorry about (...) (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) No there's not. I'm a physicist... not an engineer ;) Tim (18 years ago, 6-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions  [DAT]
 
Something else to consider is that T junctions will often appear in model files themselves between two parts as shown in this simple example. 0 Model exported from LeoCAD 0 Original name: 1 4 20.00 -24.00 30.00 1.00 0.00 0.00 0.00 1.00 0.00 0.00 (...) (18 years ago, 7-Mar-07, to lugnet.cad.dat.parts, FTX)
 
  Re: Part Authors: opinions sought on T-Junctions
 
(...) Yes, that's true, but in such cases there are generally lines separating the polygons (parts), and people expect to see those in the render. The problem we're talking about here is artifacts showing up on the faces of individual parts where (...) (18 years ago, 7-Mar-07, to lugnet.cad.dat.parts, FTX)

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