Re: [brlcad-devel] Some questions and the current status of myproject
Open Source Solid Modeling CAD
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From: p. <284...@qq...> - 2012-06-30 04:13:30
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> Different from the implicit form or different from examples elsewhere? It's different from the examples in http://paulbourke.net/geometry/superellipse/ . > Can you post a few pictures illustrating the problem? If you need > sharp corners, I think there may be a way to do that (if nothing else > using multiple surfaces, but there may be other options as well.) OK. I will post some pictures of the raytracing results from super ellipsoids with e or n > 3. I also think generating multiple surfaces is a way to get sharp corners, although it's a little bit more complicated than a single surface. > The best I can offer is the following from the documentation of the > system from which cline originally comes: > http://bzflag.bz/~starseeker/cline.pdf > If the raytrace results of cline are view dependant (I don't recall > for sure) then it cannot be represented properly as a NURBS brep in > any case. I found it's really view dependent. That's quite strange. So, what is this primitive usually used to do? > Well, if you want to undertake the next phase (going from unevaluated > CSG trees to evaluated ones) the problem that needs to be addressed is > the so-called "surface-surface" intersection problem. > There is a fair bit of literate on the topic, and a variety of > possible approaches, so if it sounds interesting you can look it over > and see what you think. Some quick links: As far as I'm concerned, that will be a great challenge for me. NURBS intersection is another GSOC project and is marked as 'hard'. So I will read the papers you offer in a few days, and find out whether I can manage to do it. Cheers! Wu |