artefacts caused by ies-light?

[max montana]

i can´t get rid of the artefacts in the wall. even if i rise the refl. subdiv. to 128.
i think the cause is not the material, but the ies-light in the floor, as around the ies-lights above there are no artefacts in the wall.
is there a possibility that i adjust the "quality" of the ies-light, to avoid these artefacts? the only thing i find there is a subdiv. counter in the vray shadow parameters, but tweakening this one brings no result.

[vlado]

Have you tried disabling the "use light shape" option for the IES light?

Best regards,
Vlado

[simmsimaging]

I think this is a problem I had with IES lights too. Isn't it true that if you turn off 'use shape' you lose the realistic reflections (the area light type reflections) of the IES light? If it's the same problem I think Vlado had mentioned it as something that might be optimized later so the noise was more in line with Vraylights - is that still a possibility, or is this something different?


b

[vlado]

Isn't it true that if you turn off 'use shape' you lose the realistic reflections (the area light type reflections) of the IES light?

Yes, but in this scene there aren't visible speculars anyway.

If it's the same problem I think Vlado had mentioned it as something that might be optimized later so the noise was more in line with Vraylights - is that still a possibility, or is this something different?

It is not as easy as for the VRayLight's; for the noise to be similar to area lights, the IES lights will have to have actual shape. However there is no good way to associate a web profile with any particular shape - the standard itself assumes the lights are regarded as point lights.

In newer versions of V-Ray there is an option to use the light shape for shadows, but not for speculars - in many cases this is enough to reduce the noise.

Best regards,
Vlado

[max montana]

ths is one of the most insistend problemms i struggled with.
i made about 30 rendertests, tried really everything.
first i tried your suggestion, then other ies, then unchecked all ies in szen and lit it only with a vraylight/plane,...artefacts stay.
so i think it is the material or geometry, try an override material rgb 200 without refl. on the whole szene, and build a new wall, the artefacts are still there.
then i delete all lights in the szene, add a vraysun/sky and the artefacts are gone....
but still dont know what exactly causes the problem.

[pengo]

could it be related to a too much intense light problem when it is too close to surfaces like a wall or so on?
Because sometimes i found it too.

[max montana]

in my case not as i deleted all ies-lights and added only one vraylight(plane) in the scene which was about 4 meters away from the area with the artefacts.