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 CAD / Ray-Tracing / 1579
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Subject: 
Re: Outlined part edges in L3P?
Newsgroups: 
lugnet.cad.ray, lugnet.inst
Date: 
Mon, 23 Dec 2002 02:35:45 GMT
Viewed: 
1897 times
  
In lugnet.cad, Kevin Clague writes:
Hi Lars,
  I was wondering if you had ever considered adding a feature to L3P to
provide the lines at edges of bricks, so that we don't have to use MEGAPOV
to do so?  The advantages are that we would not have to play with MEGAPOV
settings to get them just right, depending on the resolution of the model.
MEGAPOV is not perfect in its edge detection mechanism, and we wouldn't have
to wait for MEGAPOV to post process each image.

  Is there a way to do so?  It seems like it might fit nicely with the
"smooth triangle" algorithm you are developing this spring.

First, I don't think that it is related to the "smooth triangle" algorithm,
because this is independent of the scale of the triangles,
it only deals with their surface normals.

The basic problem is, that there is no such thing as a line in PovRay.
PovRay deals with 3D objects.
Well, a line could be rendered as e.g. a black cylinder.
But suppose that a 1x1 brick and a 2x2 brick both use box.dat.
If the lines in box.dat were converted to black cylinders,
these cylinders would appear twice as big in the 2x2 brick,
because it scales box.dat twice as much as the 1x1 brick does.

That could be overcome by "inlining" box.dat and all other subfiles,
but it would result in huge .pov files.
(which might be OK - probably the rendering time would remain the same)

Hm, I'll think I'll do some investigation/experiments.
It would also require a new way of doing primitive substitution
because the edge "lines" would have to be dynamic regarding the scale.

Another related item I have sometimes wondered about is how to make
rounded edges (in stead of black outlined edges), but that's more difficult,
because it would require the adjoining surfaces to be clipped.
/Lars



Message has 2 Replies:
  Re: Outlined part edges in L3P?
 
"Lars C. Hassing" <lch@ccieurope.com> skrev i meddelandet news:H7JwBt.7t1@lugnet.com... (...) Perhaps L3P could collect all the edge lines during part generation, but defer the output until the complete model has been generated, and then write (...) (22 years ago, 23-Dec-02, to lugnet.cad.ray, lugnet.inst)
  Re: Outlined part edges in L3P?
 
I realized that this suggestion might work fine for rectangular parts, but cylindrical parts won't have edge lines along the cylinder walls, right? Kevin (...) (22 years ago, 23-Dec-02, to lugnet.cad.ray, lugnet.inst)

Message is in Reply To:
  Outlined part edges in L3P?
 
Hi Lars, I was wondering if you had ever considered adding a feature to L3P to provide the lines at edges of bricks, so that we don't have to use MEGAPOV to do so? The advantages are that we would not have to play with MEGAPOV settings to get them (...) (22 years ago, 22-Dec-02, to lugnet.cad)

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