noise in glossies - found the initiator

[themaxxer]

after uncountable renderings and frustration about the noise in the glossy reflections I finally found the problem.

the problem is the glossy texture, if you take one. without a map the glossies are clean and nice, but with a map (texture) all is messed up. you have no chance to get clean glossy reflections, also with 100 subdiv. It took me a while to figure it out.

without a texture...

nice and clean

with a texture...

noisy!

ehm, vlado... is there a workaround or trick?

best regards
themaxxer

[vance3d]

Can you describe your shader comparisons a bit more. for the unmapped what was the numeric glossiness value? and in the mapped version what did you supply as a map (vray color, parametric texture or bitmap) and also was the glossiness value something other than 1?

I am very interested in this as I've been experiencing similar issues but never figured it could be the map.

V Miller

[PIXELBOX_SRO]

try using a bit of filtering there within the map params...i used to get this too until i ve figured yout its the filtering left at really low value that caused it
PLUS
try upping your DMC to something like 1/8 maybe more and see what it does

if you PM me, ill send you a vray preset you can play with if you want

[themaxxer]

Can you describe your shader comparisons a bit more. for the unmapped what was the numeric glossiness value? and in the mapped version what did you supply as a map (vray color, parametric texture or bitmap) and also was the glossiness value something other than 1?

I am very interested in this as I've been experiencing similar issues but never figured it could be the map.

V Miller

the numeric value was 0.7 for the unmapped version. in the mapped version I've used a bitmap for the glossy effect. I think the same as for bump. the glossiness value is about 1, BUT if you render with solidrocks and want to use "Interp. gloss in IrrMap" then ypu have to use a lower value (0.75) to tell solidrocks that its a glossy reflection. without that solidrocks wont optimize the material at all.

I have made several more tests and I have figured out the noise problems comes from the VraySky light (map) I have lights in skylight mode, but nothing helps to get rid of the noise except raising the DMC values to 1/16! this causes high rendertimes.

[instinct]

Well if the mapped version is causing a lower glossiness value then you'd need more subdivisions than without the map no ?

[themaxxer]

Well if the mapped version is causing a lower glossiness value then you'd need more subdivisions than without the map no ?

that's right. but both versions are almost the same.

[instinct]

Tough to say in the screenies. If they are about the same glosiness-wise then they are a lot weaker. Less contribution to the RGB means less samples, so maybe that's a culprit there?

Just wildly guessing.

Regards,
Thorsten

[themaxxer]

hm, very interesting guessing. so you mean the result is a third of the value 0.7?

best regards
themaxxer

[bardo]

and if you use as bitmap a full grey texture with a RGB values as 255x0.7=178 the result is the same as unmapped or the noise shows up again?

[pixela]

If they are about the same glosiness-wise then they are a lot weaker. Less contribution to the RGB means less samples, so maybe that's a culprit there?

Can you please explain what this means?