 | | Re: CW/CCW, vertex sequence, co-planar, convex —John VanZwieten
| | | | It seems to me that there are two major "camps" in the CW/CCW debate. A. Face-by-Face Method This method suggests that CW-ness be ultimately evaluated on a face-by-face basis. Each quad in a primitive or part would hold a value of CW,CCW, or (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Gary Williams
| | | | | John VanZwieten wrote in message ... (...) Actually, I count three ideas. (...) messy. (...) when (...) the (...) to (...) only (...) have (...) in (...) CW (...) slightly (...) for (...) The third option, which I believe would be best, is similar (...) (25 years ago, 4-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Lars C. Hassing
| | | | | Gary Williams wrote in message ... (...) Well, inside/outside-ness also counts. It doesn't make sense to certify a part before ALL its subfiles have defined what is inside/outside. Until then you cannot determine whether or not you need any INVERTS. (...) (25 years ago, 8-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Jacob Sparre Andersen
| | | | | | Lars mentions the problem of "uncertified" parts using "certified" primitives. Is it so much of a problem? <much thinking> I can't find any other easy solution than using different names for the "certified" versions of the _primitives_. That way we (...) (25 years ago, 8-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Lars C. Hassing
| | | | | | | Jacob Sparre Andersen wrote in message ... (...) Certified primitives are harmless when used by old uncertified parts, so there's no need to create special certified versions. And in stead of fixing parts to reference the new names, you might just (...) (25 years ago, 8-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Steve Bliss
| | | | | (...) Checking the order of points in a file should not depend on checking the inversion or subfiles for the file. That's why we've been talking about the 0 FACE UNKNOWN -- so parts of files can be fixed, even if the entire file can't be addressed. (...) (25 years ago, 8-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Lars C. Hassing
| | | | | (...) Yes, you can of course settle for checking only the tris/quads of a file and put UNKNOWN around subfile references. But then you would miss the most important speed boost coming from the primitives, which are responsible for the majority of (...) (25 years ago, 9-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Steve Bliss
| | | | | (...) Understood and agreed. (...) Also, the primitive files will (generally) require less work than most part-files. [About introducing processing-by-file-type] (...) Yes, if they didn't have a 0 CLIPPING ON directive. That's why I said a good (...) (25 years ago, 11-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Lars C. Hassing
| | | | | (...) Yes, this works for *new* models/submodels. Will you really require all existing models to go through a new good editing program, before they could benefit from backface-culling? I don't think that is necessary. Once an old model references a (...) (25 years ago, 11-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Steve Bliss
| | | | | (...) Sure. But I also feel that it would make sense for rendering programs to give the user control, so that clipping can be set to default to off, or default to on, or to be totally disabled. (...) If a certified part-file can turn clipping on, (...) (25 years ago, 13-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Lars C. Hassing
| | | | | Steve Bliss wrote... (...) Yes, rendering programs should have these reasonable options. But I think it is safe to start clipping from opaque certified parts. (...) Parts are objects with obvious orientation. You are not in doubt what is (...) (25 years ago, 14-Oct-99, to lugnet.cad.dev)
| | | | | | | | | | | | Re: CW/CCW, vertex sequence, co-planar, convex —Steve Bliss
| | | | | (...) Disagree. Being able to turn clipping on and off separately from specifying the direction of winding is a functional difference, not 'syntax sugar'. (...) OK. Steve (25 years ago, 15-Oct-99, to lugnet.cad.dev)
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