Hello Mark,

on Montag, 15. Oktober 2007, 17:58:56, you wrote:

> Hi Marc,

> Well done: a very important subject, everybody dabbling with 3d will have to
> deal with this.

> My 2 cts: the aliasing problem can also occur in procedural textures. 

And not only there, but also the problem exists with geometry objects.
I have tried it with a fence. In it's simplest form, it's only a line
up of rectangles. When I setup up a level of 1 in the rendering
anti aliasing settings with the method “geometric” the distance
between the rectangles differs slightly. If I switch to “stochastic”
all distances are the same, but I get noise. Raising the anti aliasing
level to the max helps and improves the image qualtity. But even then
I see differences of the two methods in the rendering. So the right
method depends on the type of scene.

> There's no specific source texture size... instead, we're dealing with
> mathematical noise, cells, tiles or other pattern-generating sources. Quick
> conclusion: don't set Octaves higher than necessary and try to use material
> antialiasing (Material properties -> General tab).
> I had some difficulty setting up the AA for such materials: the Antialiasing
> value combined with Threshold, U and V samples, and this combined with the
> current Render settings... a lot of trial&error and test rendering required!

I often don’t use the anti aliasing setting of the material. Only at
very specific materials. In the rendering settings, I set a high level
of anti aliasing, often level 6 and use a high threshold. With scenes
which consists of smooth surfaces and hard edges it’s possible to set
the threshold to 100. The rendering speed is near the same as a
rendering with anti aliasing level 1, but with a great improvement in
the image quality.

> And then there's mip-mapping: switching and blending closeup and far-away
> textures depending on distance to the camera. Scripting, V6?

Interesting option, we will see if it is really useful.

> Many thanks, I hope you'll expand this page,

Yes, the page isn’t finished yet. But when times comes by I will step
by step add some more topics and refine the whole thing.


-- 
Best wishes,
 Marc Michael

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