ZBias issue

The ZBias factor is not the same for different display modes - without there being a way to control this value per display mode.

The top part of this picture shows a model in the Rendered display mode (with surface edges turned on) - the bottom part is a (modified) Shaded display mode.

Raytraced uses the same ZBias as the rendered mode.

Raytraced doesn’t know about any Rhino ZBias factor. How do you infer it to use the same?

Just by Raytraced having the same bleeding of edges through the surfaces as I see in Rendered. I didn’t try to imply that Raytraced uses that factor actively in its display - just that it seems to be using the same “information”.

Can you please create a simple test file that shows the problem. If you have time please add screenshots with the error and what you expect to see.

Thanks in advance.


That turned out to be a bit harder than I thought it would be… It seems to be related to a few 3rd party components that we use.

Anyway, here is a simplified scene but because of the simplification, the effect is less pronounced. It is much more visible in the screen shot that I posted above.

ZBias Test File - 3.7z (4.6 MB)

What I see:

What I expect to see [and was obtained by setting the ZBias factor to .1]:

Why I expect that? Because shaded display modes are less dirty with the default ZBias factor:

@wim, is that with extra goodies turned on, on top of the Raytraced view? I.e. wires and such? Those I am not drawing myself, so may be the same problem as what Rendered view shows…

@nathanletwory, as in my opening post: this is “the Rendered display mode (with surface edges turned on)”.

It was only in an additional comment that I wrote that this was also visible in the Raytraced mode. That makes sense, then, since you are not drawing those wires…

At any rate, I suppose this is something for @jeff or @stevebaer to take a look at.

@wim, I apparently need to do more “begrijpend lezen”. The surface edge drawing is indeed more @jeef, @stevebaer or @DavidEranen territory.

I have reported this as RH-41155 to track.

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No worries, Nathan! It takes two to tango…

(by the way, could you make that YT open to the public?)


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