no Anti Aliasing ?!!!!!!!!!!!

[MikeeMax]

hi, i'm doing tests for a future project.
first time i face this problem. i have no AA.... look at the settings.... same as usual for me...
scene is lit with a vray dome light(hdri) and a vray sun. bg is a vray color (whithe) set to 50.

any help would be appreciated.

Thanks

[MikeeMax]

okay i figured this was the 50 white vray color background.
How come that it has this effect on AA ?

[palibebeh]

cause the light was burning that white wall. and since vfb is displaying the image only in 8bit per channel, the burnt pixels are only an approximation of the original pixels - which are 32bit internally. the loss of detail in overbright areas is due to clamping etc.
so in essence that's not a AA issue, but overbright/burning of the pixels.

someone please correct me if i'm wrong.

[instinct]

Well the calculation is pretty straight forward. Basically speaking AA between two objects mixes the pixel from the one with the other by a weight defined by subpixel weight. No imagine a pixel that has 50% of the one and 50% of the other. That basically means pixel + pixel / 2 (plain average).

Now imagine a mid gray and the mentioned 50 float white:

0.5 + 50 = 50.5

50.5 / 2 = 25.25

25.25 is still way white. So even tho there IS AA happening it doesnt have an affect in the displayd 0-1 range.

Regards,
Thorsten

[MikeeMax]

thanks for technical explanations

[dlparisi]

You can fix this by checking "Affect background" in your color mapping rollout (this will clamp the backgroud values to 1 so that it will antialias correctly per Throsten's post.)