Is this AA problem? please help!

[CG_Utopian]

Hi,



This is a region out of a huge rendering (25,000 px) that had this problem which i couldn't solve. the rendering in general was fine except for some chamfered edges that were catching a lot of light were this problem appeared.

I increased the settings (Too much) and it didn't help. so could you please point out what is the possible cause(s) for this and how solve it? i am using Vray 3.40.

Thanks a lot

[sheehan_partners_nm]

Looks like an AA problem, sometimes it happens to me with edges of bright rectangular lights. Did you try activating sub-pixel mapping under color mapping tab?

[CG_Utopian]

Thanks for the reply, i activated it. didn't help.

[Zdravko.Keremidchiev]

You should get better AA if you turn on "Clamp output" but you will lost the dynamic of the image. You can try set it to a larger value than 1 in example 2-4 and check whether it will still fix the issue while you still have some dynamic left. Also make sure that you are not using sharpening filters as Mitchell-Netravali in example.
You can also smooth this area with lens effects.

[CG_Utopian]

You should get better AA if you turn on "Clamp output" but you will lost the dynamic of the image. You can try set it to a larger value than 1 in example 2-4 and check whether it will still fix the issue while you still have some dynamic left. Also make sure that you are not using sharpening filters as Mitchell-Netravali in example.
You can also smooth this area with lens effects.

Seems that clamp output will work only in combination with sub-pixel mapping, and only if the clamp output is set to 1.0, any increase above one makes the problem appear again.

[R2J2]

when you have samples that are well above 1 the image sampler has to do a lot of work to resole that.
On a camera image sensor a similar thing is happening it's just that these intense highlights will bloom/spill out into the neighbouring sensor pixel, so the options are either subpixel map and clamp like CG_Utopian said or in comp luma key those hot pixels and add blur/glow. This would simulate what a camera sensor is doing.