sub-pixel and clamp output on/off question

[Fekta.studio]

Hi all.
Here is a test of a scene Im working right now, I made some tests on a settings. It seems that, if I turn sub-pixel and clamp output on, render is done for 5.32 sec (pic1), if I turn it off render goes up to 14 min....(pic2), actualy u can see the diferences between both pix , but its not worth the extra minutes....
its LWF.
Is that normal?
Sorry for the crap renders, after all its just a test..


[pic1]


[pic2]

[vlado]

Yep, it is normal. With the clamping off, V-Ray needs to shoot more samples to clean up the glossy reflections on the floor. With the clamping on, the reflections are dulled, as you can see, which makes the job of the image sampler easier.

In cases like these, it may be useful to increase the subdivs for the glossy reflections, rather than rely on the image sampler alone.

Best regards,
Vlado

[Fekta.studio]

thx Vlado for the fast respond. Now im aware of that clamp option another one, i set the glossy samples (subdivs) of materials to 100 ,I did try it at 25, 32 and so far till i reach 100, non of those clean the glossyes at all, DMC are set to 0.001, and adaptrive DMC is tryed at 1/4, 1/6. 2/6, 1/32, 1/64, 1/100, 2/100 - no clean glossy so far..

Well the strange is when I set it to 2/100 ,and all the glossy samples(subdivs) in materials to 100, render times is lower than any of the settings I mention above, and glossy mat are cleaner, the DOF is cleaner too. Is that normal too, adaptive ammount is 0.85/IR map and LC is default, LWF, DE is on for IR map.

I get the most reasonable render times with that settings, I forget to mention the scene is render in DR.


PS. I didnt touch the min samples and global subdivs multiplier at all. Should i do it?
the renders above is with noise treshhold set to 0.007 just for fast render. DMC 2/100, mat subdivs 100

[duke2]

thx Vlado for the fast respond. Now im aware of that clamp option another one, i set the glossy samples (subdivs) of materials to 100 ,I did try it at 25, 32 and so far till i reach 100, non of those clean the glossyes at all, DMC are set to 0.001, and adaptrive DMC is tryed at 1/4, 1/6. 2/6, 1/32, 1/64, 1/100, 2/100 - no clean glossy so far..

Well the strange is when I set it to 2/100 ,and all the glossy samples(subdivs) in materials to 100, render times is lower than any of the settings I mention above, and glossy mat are cleaner, the DOF is cleaner too. Is that normal too, adaptive ammount is 0.85/IR map and LC is default, LWF, DE is on for IR map.

I get the most reasonable render times with that settings, I forget to mention the scene is render in DR.


PS. I didnt touch the min samples and global subdivs multiplier at all. Should i do it?
the renders above is with noise treshhold set to 0.007 just for fast render. DMC 2/100, mat subdivs 100

VRay has some internal math controlling the DMC engine which i've never fully grasped. All I know is Lele has some scripts that will help you with this kind of stuff. Other than that, try you original settings but with the DMC adaptive amount at 0.5.

[Fekta.studio]

VRay has some internal math controlling the DMC engine which i've never fully grasped. All I know is Lele has some scripts that will help you with this kind of stuff. Other than that, try you original settings but with the DMC adaptive amount at 0.5.

thx for the tip, but the only clean render I can get is with the 2/100 DMC / 0.001 treshhold .
If i set it to default I get clean some parts, other remain with noise. seems this is the best option so far.