Subject:
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Re: The use of type 5 lines for smoothing of objects.
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Newsgroups:
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lugnet.cad.dev
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Date:
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Wed, 8 May 2002 18:49:24 GMT
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Viewed:
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437 times
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> One thing that someone noted (I think it was Don Heyse) when I mentioned
> this was that it might be possible to instead check for the lack of type 2
> lines of color 24 between two adjoining faces, and use this as an • indicator
> that the two faces should be smooth shaded. This would solve the problem • on
> the inside of the minifig hand, but it may produce smooth shading in • places
> where it is undesirable. Most of these could probably be avoided by • having
> a maximum difference in angle between the two faces. On the other hand, I
> think your algorithm would be MUCH easier to implement.
>
> --Travis Cobbs (tcobbs@REMOVE.halibut.com)
This looks indeed like a more general way to do it. A big problem however
will be complex patterns on a face, like on a shield. There will be a lot
useless checking, because for every edge in a face you have to check for a
color 24 line. If not present you have check for neighbors are in the same
plane or not. You also may have to look beyond the scope of the dat file to
see how primitives or sub files are connected. This will increase complexity
enormously. In the optional line case it is possibly to stay in file scope
(in almost any case, and in any case if border optional lines are added).
There is also the orientation problem in non-bfc files. It is easier to
adapt current files by inserting type 5 lines at edges that are smooth,
because type 5 lines are more or less meant for that. This can be done
without backward compatibility issues. The only drawback is decreased
performance when viewing with viewers that actually use optional lines to
draw a contour.
Modern viewers with perspective view should also be able to display optional
lines to draw a contour. This can be done in almost the same way as in an
orthographic view, but now you check if the last 2 points are on the same
side of the plane, defined by the first 2 points and the point of view. This
is the general case of the optional algorithm.
Martijn Zwaal
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Message has 2 Replies:
 | | Re: The use of type 5 lines for smoothing of objects.
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| Hmmm, Finally a use for the type 5 lines I've been ignoring :) (I have another - so far successful - way of drawing in those lines) (...) Well alot of this leads in a direction I've mentioned before. Which is adding strip and mesh info into the (...) (22 years ago, 8-May-02, to lugnet.cad.dev)
| | | Re: The use of type 5 lines for smoothing of objects.
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| (...) I tend to agree with you. My suggestion to Travis was based on about 2 seconds of thought when I read his email. It occured to me that type 2 lines are used to denote hard edges so I mentioned the possibility of using them instead of type 5 (...) (22 years ago, 8-May-02, to lugnet.cad.dev)
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Message is in Reply To:
| | Re: The use of type 5 lines for smoothing of objects.
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| (...) One thing that someone noted (I think it was Don Heyse) when I mentioned this was that it might be possible to instead check for the lack of type 2 lines of color 24 between two adjoining faces, and use this as an indicator that the two faces (...) (22 years ago, 8-May-02, to lugnet.cad.dev)
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