What's Up With Texture Filter Types?

[aaronk]

By default maya sets the filter type of each texture to "Quadratic". But whenever rendering with mental ray, and looking into render diagnostics, it always throws warnings for each texture, that quadratic filter type is not supported by mr. So I tried seting all filters to "Off". The warnings no longer appear, but the render takes about 20% longer. (Also when set to "off" the textures are much sharper on the render). So which filter should I use for mr, so that the renders dont take longer, but no warnings will be thrown?

[gmask]

Via process fo elimination you can figur eout which ione wil nto throw warnings..
'
Otherwise I typically turn off filtering unless I get a crawl in the texture.

[aaronk]

QUOTE(gmask @ 08/10/07, 08:19 PM) [snapback]271316[/snapback]
Via process fo elimination you can figur eout which ione wil nto throw warnings..
'
Otherwise I typically turn off filtering unless I get a crawl in the texture.

Ok, so I tested some filtures and got pretty strange results. I got the fastest render time with "Box" filter, but it's also the must blury one - and I want sharper results, at least for some objects in the scene. I got the best looking results from mipmap filter, but it's a bit longer to render (although faster than "Off"). So I decided that the best option would be to use the fastest filter (Box) to most textures, and Mipmap filter to those in which I require sharper results (only 4 textures, out of 50+) and I got even longer render time than using the Mipmap to all textures. Does that mean that mixing couple filter types takes even longer? Anywasys - im gonna stay with the Mipmap filter for now then.

[joojaa]

Well you could try to use a mentlray file node and the elliptic filtering. which is for mr the best possible filter.

Also, you can speed up mipmapping and render performance by saving your textures as map (wich is a pyramidial lookup format of mentalray, it also saves a lot of memory for you), use imf_copy form command line for this. You can even do the pyramids yourself for a potentially even more sharp results.

PS. please note the sharper your render result the more prone your image is to temporal aliasing (flicker!)

[toast--2]

Yes, sharperning your images in post with "unsharp Mask" I found is the best way to get sharp renders.

[aaronk]

QUOTE(Joojaa @ 08/11/07, 06:56 PM) [snapback]271358[/snapback]
Well you could try to use a mentlray file node and the elliptic filtering. which is for mr the best possible filter.

Also, you can speed up mipmapping and render performance by saving your textures as map (wich is a pyramidial lookup format of mentalray, it also saves a lot of memory for you), use imf_copy form command line for this. You can even do the pyramids yourself for a potentially even more sharp results.

PS. please note the sharper your render result the more prone your image is to temporal aliasing (flicker!)

What do you mean by mentalray file node? You mean "mentalrayTexture" node from create mr nodes menu?
To be honest I'm more into speeding up the performance than creating sharper results, because as some of you said here I can sharpen it a bit in postproduction if neccessary.
I do use .map format for larger textures (like 2k), but this scene doesnt use any larger than 1k, and I didnt notice any speed ups in performance when using the .map so I just sticked with tif textures for the time being. As I said, I use map in some scenes with larger textures.

Anyways Im setting up another scene right now, and mipmap filter type seems to slow down the rendering much more than before, so I guess Im gonna have to go back to quadratic in this case

[gmask]

Well personally I don't think using sharpen is a great way to go but the reason to use map files is when you have very large textures it is easier for the renderer to use a map file with the alotted ram.

[joojaa]

QUOTE
What do you mean by mentalray file node? You mean "mentalrayTexture" node from create mr nodes menu?

mib_texture_filter_lookup

QUOTE
Well personally I don't think using sharpen is a great way to go but the reason to use map files is when you have very large textures it is easier for the renderer to use a map file with the alotted ram.

I agree, sharpening will just bring you closer to the other spectrum of the problem namely temporal aliasing. The filtering is a in place to roughly simulate the fact that your sample should not represent just one value but the integrated effor of all pixels involved in the sample size.

This is a tradeoff, between stable image versuss sharper result. Whereas filter type is a Trade of between speed and quality.

Yes map saves memory, but is also saves times doing mipmapping since the mip mapping is already pregenerated, and controllable.

A suitably designed map with different colors on each mipmap layer also enables you to analyze the needed resolution fo the image as a bigger image just produces worse results at slower times rather than sharper results. Sharpness is a big compound between te rebuilding filter and signal field. I suets you use a lancoz for rendering as this sharpens things up. Alternatively write a catmul-rom or sinc filter.