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![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) One problem: transparent surfaces would show the wireframe backside. :\ Steve (22 years ago, 18-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| I was reading through this more, and while I still don't know exactly how it all works, I think I stumbled onto something. > I dont know how many of you have come across this technique before. I > remember finding an OpenGL demo that did this kind (...) (22 years ago, 18-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) Yeah, the stencil buffer, that's gotta be it. If you've got BFC working then you can use the stencil buffer to count how many times an edge is draw in GL_LINE mode. Edges on back facing triangles won't be drawn, so you'll only count one edge (...) (22 years ago, 18-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) That sounds like glPolygonOffset which would be part of the solution because it allows the edges to look clean. We all use that already. (...) I can see how you might accomplish some of that by manipulating glEdgeFlag when you define your (...) (22 years ago, 18-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) OpenGL has glPolygonOffset, which does what you describe by allowing you to move the polygons further away in the Z direction, where the amount they move can depend on the slope of the polygon in the Z direction. This works great, and I use it (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) The obvious case where it's useful is studs - without these lines, viewing any brick from the standard "oblique" position above & to the side, you would see a circle at the top & bottom of each stud, but no sides, which IMHO would not look (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) Well, I believe that there is something called a 'Z offset' that can be used not to actually move the geometry, but to make sure the lines appear 'on top' of the faces. Before I go more into this I need to back up a bit. I currently use the (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) I'm curious to. Everything I know about how OpenGL works says that drawing the strip as a wireframe after drawing it solidly would either produce Z Buffer noise, no wireframe at all, or wireframe all over. However, it may be that there is some (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) Tell more about this. I just tweaked a version of ldview to display type 5 lines, but only for surfaces that haven't been replaced by quad strips. It looks good with primitive substitution turned off, but with this automagic wireframing of (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
| | ![](/news/x.gif) | | Re: Why Type 5 Lines?
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| (...) I believe that there are other ways to put these lines in, as long as you are *only* planning on using them to show the 'visible' edge of a curved surface. This is actually a question I've been meaning to ask around here, Have type5 lines been (...) (22 years ago, 17-Apr-02, to lugnet.cad.dev)
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