Question about default AA filter

[LudvikKoutny]

Hi,

I am a bit curious about why V-Ray Lanczos was chosen as a default filter. First thing that interests me is that V-Ray docs say:

Avoid using filters with negative components (sharpening filters) like Catmull-Rom or Mitchell-Netravali when using the Progressive sampler as this may increase the render times quite a bit - the sampler needs to take additional image samples to resolve the filter.

From what I understand, Lanczos falls into sharpening filter category as well, as the curve profile goes into negative values as well. And if V-Ray somehow worked around it, then it would cease to be Lanczos filter, or am I wrong?

Next question is, since Lanczos is pretty sharp filter, is suggested to use it also for animations? I mean, is Lanczos with 2.0 width meant as a good default for just stills, or all around good default?

Thanks.

[joconnell]

Here it is from wikipedia:

"The Lanczos filter has been compared with other interpolation methods for discrete signals, particularly other windowed versions of the sinc filter. Turkowski and Gabriel claimed that the Lanczos filter (with a = 2) the "best compromise in terms of reduction of aliasing, sharpness, and minimal ringing", compared with truncated sinc and the Bartlett, cosine-, and Hann-windowed sinc, for decimation and interpolation of 2-dimensional image data.[1] According to Jim Blinn, the Lanczos kernel (with a = 3) "keeps low frequencies and rejects high frequencies better than any (achievable) filter we've seen so far."[3]"

I've found it to be pretty similar to area in look, I've done a job recently with a slow camera move over a park with lots of trees and I didn't get anything really sharp or sizzly like I would have with mitchell or catmull. Rather than enhancing edge crispness, it seems to try to just keep the detail. Vlado thought it was fairly high quality and not much different in overhead to area.

[vlado]

The VRayLanczos filter in V-Ray is not a sharpening filter; it is similar to the area filter but with reduced moire effects.

Best regards,
Vlado

[LudvikKoutny]

Ah,

now it makes sense. Thanks to both of you

[Macker]

Nothing makes my eyes bleed more than the prevalence of sharpening filters in arch vis.

[jasonhuang1115]

The VRayLanczos filter in V-Ray is not a sharpening filter; it is similar to the area filter but with reduced moire effects.

Best regards,
Vlado

Vlado and John, is the Lanczos filter in Maya equal to Max's VRayLanczos filter? If not, would the Lanczos filter with size 2 still the recommended filter for Maya users?

[vlado]

It's the same filter. I would still recommend size 2, yes.

Best regards,
Vlado

[jasonhuang1115]

It's the same filter. I would still recommend size 2, yes.

Best regards,
Vlado

Thanks for the confirmation, Vlado.