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 CAD / Development / Organizations / LDraw / 4740 (-10)
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Hmmm, it seems to me that any algorithm that can find the missing Type 5 lines (in order to create the dummy entries) should be able to find *all* of the Type 5 lines. Some missing lines is just a special case of all missing. So just include (...) (14 years ago, 23-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Actually, no. That is indeed a long-term goal, but it is hampered by two things. First of all, it's a lot of work. Secondly, the current algorithm is actually useful to part authors, since it can visually highlight missing conditional lines. (...) (14 years ago, 23-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Sorry for that ;o) But (fortunately) here are very few twisted surfaces in LEGO pieces, so I don't think my tool has created too much havoc... (...) Problem is that at this low level I have almost no information about the intended geometry - I (...) (14 years ago, 22-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) I see. So what you really want to do in LDView is ignore the Type 5 lines (at least for smoothing) and smooth wherever there's no Type 2 edge lines between the triangles (and quads). (...) Did anybody ever did actually fix the parts though? I (...) (14 years ago, 22-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) algorithm. LDView uses Type 5 lines in the LDraw file for smoothing, and considers any two surfaces that have a Type 5 line joining them to be part of a smooth curve. The problem is that two co-planar triangles sitting next to each other (...) (14 years ago, 21-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Isn't this the same problem we ran into with the twisted wedge bricks a while back? Those gave us problematic conditional lines in addition to the ugly zigzag shading artifacts. (URL) thought the solution was to orient the triangles orthogonal (...) (14 years ago, 18-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Note that I consider this behavior to be a bug in LDView, and as such I will fix it when I get a chance. --Travis (14 years ago, 17-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Re: Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) Good question! + reduces file size by 50% + 50% less vertices to adjust when building "by hand" + triangles plays havoc with smooth shading (the helical artefact that can be seen here (URL) disappears when triangles are converted to quads. But (...) (14 years ago, 17-Sep-10, to lugnet.cad.dev.org.ldraw)
 
  Why quads? Re: L(EGO)Draw parts - 4th batch
 
(...) I realise this is largely off-topic to the oriinal thread but I've always been curious why the use of quads is encouraged when just about every other format and rendering engine sticks to triangles. So the part author merges triangles into (...) (14 years ago, 16-Sep-10, to lugnet.cad.dev.org.ldraw, FTX)
 
  Re: L(EGO)Draw parts - 4th batch
 
There is one more thing to add to Joshua extensive explanations: coplanar triangle pairs are not assembled into quads. I advocated for that, because it offers the maximum flexibility when splitting into subparts or adjusting vertices position (no (...) (14 years ago, 16-Sep-10, to lugnet.cad.dev.org.ldraw, FTX)


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