Production render globals

[FredrikS]

Hi All,

I'm a complete newbie with Vray so please keep that in mind with your potential answers.
And just to let you know our company do film vfx so that is the kind of renders we are doing, as opposed to architecture or product design.


Iv'e watched some tutorials where they suggest to use the 'nenderhorst' settings. They seem to work pretty well in my test scenes.

I do have to set the Adaptive DMC Threshold down to 0.002 to get rid of the noise from my hdri VrayLightDome. Is that expected?
Do people use any methods to use a blurry map for diffuse and a sharp one for glossy reflections?


Do people actually use the nenderhorst method for their production renders or are there some exception cases I should know of?
Special setting for motion blurred scenes?
Indoors vs outdoors?


Any tips on render globals used in actual production would be greatly appreciated.



cheers
fred

[vlado]

I do have to set the Adaptive DMC Threshold down to 0.002 to get rid of the noise from my hdri VrayLightDome. Is that expected?
Do people use any methods to use a blurry map for diffuse and a sharp one for glossy reflections?

Normally V-Ray does a good job of sampling the HDRI properly; cases where you have many bright parts in it might take more samples though. Increasing the dome light subdivs above the AA subdivs may help to clean the noise faster (more rays will be used just for the light, as opposed to starting a new path from the camera each time).

Do people actually use the nenderhorst method for their production renders or are there some exception cases I should know of?

Apparently they do, although actual settings may differ slightly depending on the particular scene. One thing that you should keep in mind if you use VRayDirt as additional AO pass - do not set the "Adaptive amount" option to 1.0 as in the original PDF; a value like 0.9 will work better, especially if you raise the VRayDirt subdivs above the AA ones.

Special setting for motion blurred scenes?

Nope; with the Nederhorst settings, motion blur (and DOF) are essentially free (they become part of the AA).

Indoors vs outdoors?

For indoor scenes, you will want to use the light cache as a secondary GI engine (and brute force as primary). This will speed up GI quite a bit. Newer builds also have a "Retrace" option for the light cache which helps to avoid flickering and removes some artifacts previously caused by the "Use light cache for glossy rays" option. For outdoor scenes, where you don't need that much light bouncing, you can use brute force GI for both primary and secondary bounces and avoid the complexity added by the light cache.

Hopefully other people will post additional views on this

Best regards,
Vlado

[FredrikS]

Hi Vlado,

and thanks so much for the reply.

I am just sitting and trying to tweak a particular scene with a hdri lightdome where the map has several bright hotspots.

I am trying to lessen the diffuse noise by changing the LightDome settings local Sampling->Subdivs, that was set to 8 I tried up to 256.
But nothing changes.
The scene is using the Nederhorst setting which I seem to remember involves having DMC Sampler->Adaptive Amount to 1.0, which should override any local(light) settings with purely global ones. Is that right? In which case local setting wouldn't change anything?

Also, I don't see an improvement even with Adaptive Amount set to 0.0 and the dome's subdivs set to 128.


[EDIT] ACTUALLY This thing below does not happen, I must have fiddled with something else!
"Another thing I was wondering about was the GI On-Off render globals setting with LightDomes.
My scene is just one piece of geometry and only one light, that LightDome.
There seems to be a difference in the diffuse look when I tick GI on and off. Even though there is no other geometry in between the shaded surface and the dome, or indeed in the scene at all.
I was expecting it to be a purely 'direct' light?"


cheers
fred

[Zdravko]

Can you attach some screenshots with and without GI?