lights support for RT GPU

[BVA]

I have just started some RT GPU tests earlier today. My lights all seem very hard, no soft shadows. Is this a GPU limitation or a setting I miss somewhere?

[vladimir.nedev]

What kind of lights are you using ?
The "Soft edge" of "Spot lights" is supposed to work, but from my tests it doesn't (in RT GPU).
Also the "Falloff type" seems to be broken in RT GPU for point and spot lights, so they render with a very different intensity right now.

Greetings,
Vladimir Nedev

[BVA]

What kind of lights are you using ?

a point light with a radius. it render smooth in vray and RT cpu but not in RT GPU

[vladimir.nedev]

a point light with a radius. it render smooth in vray and RT cpu but not in RT GPU

In this case, you can check "Make spherical light" from the "V-Ray Light" properties.
The spherical light should work much closer in RT CPU/GPU (might work exactly the same actually).

Greetings,
Vladimir Nedev

[BVA]

When using more than one gpu, does vray automatically add them or do i need to set it somewhere?
Also, is there a way to test or know if all the gpu's are working together?
Last question, is it possible to select one or more gpu's for rendering and leave one for display, not rendering?

[BVA]

In this case, you can check "Make spherical light" from the "V-Ray Light" properties.
The spherical light should work much closer in RT CPU/GPU (might work exactly the same actually).

Greetings,
Vladimir Nedev

I tried adding the "make spherical" but then the light intensity also need to increase from 10 to a 1000 just to see the light. Is this right?

[vladimir.nedev]

I tried adding the "make spherical" but then the light intensity also need to increase from 10 to a 1000 just to see the light. Is this right?

I think it is. When you switch from point to spherical, the light starts having an actual surface.
The Radiant Intensity channel is in "Watts per square meter per steradian", so the total light power depends on the surface area of the light (just like the "Area" light type).
This means it will no longer match the total power of the point light, unfortunately.

Edit: you can increase the surface area by increasing the radius.

Greetings,
Vladimir Nedev

[vladimir.nedev]

When using more than one gpu, does vray automatically add them or do i need to set it somewhere?
Also, is there a way to test or know if all the gpu's are working together?
Last question, is it possible to select one or more gpu's for rendering and leave one for display, not rendering?

You can look in the Event log, just after you start RT GPU. It will say something like "Querying for CUDA devices...". You will see the info you are looking for after that line.

You can use the "ocldeviceselect.exe" to select the GPUs which V-Ray RT GPU will run on.
I still haven't added a shortcut to it in the V-Ray for MODO start menu entry, but you can find it in the installation folder (usually C:\Program Files\Chaos Group\V-Ray\MODO 701, 801 for x64) in the "vraysl" sub-folder.
I will need to integrate this functionality directly in V-Ray for MODO, like it has already been done in V-Ray for 3ds Max. The core stuff is already in place.

Greetings,
Vladimir Nedev

[Margarita.Stoeva]

You can now specify the GPU(s) used for rendering from the Start menu. The shortcut is found in the Chaos Group folder > V-Ray for MODO > Tools > Select OpenCL devices for V-Ray RT

Greetings,
Margarita

[vladimir.nedev]

a point light with a radius. it render smooth in vray and RT cpu but not in RT GPU

By the way, this was fixed by the RT GPU guys at some point.

You no longer need to enable "Make spherical light".

Greetings,
Vladimir Nedev