Why are there these Splotches?

[sv]

Why do you think there are they coloured splotches in this image?



There is nothing fancy about any settings, IR medium & LC 1400 screen (not used for glossies), but it is quite a comlictaed set up - there is a spherical vray light in each of the downlighters you can see.

I'm wondering if it's a material problem because it seems to be alright when a mid grey material is used for an override material....
Don't think i've got any interpolated materials....
The lights are on 'store with irradiance map because there are so many of them - 38 in three instance groups - could this be causing a problem?
All mateirals are Vray materials.....
Vray Physical camera....
Each 50Watt downlighter has a luminous value of 700lm........
No displacement..........
Reinhard colour mapping at 1 / 1 / gamma 2.2
No environment maps........

Any thing that springs to mind - such as ticking 'Max compatible ShadeContext'.....

[instinct]

hmm...might this also be a case of oddities when GI caustics are enabled (wich the are by default ?) Just a shot into the blue as the grey mat works.

Thorsten

[sv]

hmmm, interesting. I'll have a look into that.

Also, forgot to mention that i haven't enabled the other caustics rollout, but yes i'll have a look into the GI Caustics....

[DanielBrew]

Hi Steve,

Can I ask why you have made the light fittings with a spherical vray light in each fitting instead of say a plane slightly below the fitting or an IES spotlight slightly below?

Cheers

Dan

[sv]

basically i didn't use IES because too be honest i'm not sure i've got an IES file for a 50watt downlighter bulb - i also think i see the same IES lighting file being used over and over again by loads of people (even me) and didn't want to see that same lighting distribution in these images.

Also, Vray lights are easy to use when you know proper lm or wattage values, and the fall-off of Vray lights is physically correct.
I like the way the light hits the walls and appears to be spotlights - this is just the natural bounce from the vray sphere lights; they aren't targetted like a spot light...

I do take your point however that maybe a plane light might be easier to calculate, so i could give this a try.
The only thing is i wouldn't want to position it below the light, as i want to be able to clearly see the downlighter rims... Perhaps level or just above it pointing down - (in this scene the roof has been modelled with 'holes' in the mass where the lights go. This way i put the sphere light in the hole and just let vray calulate where the light would go.

At this point i'm not precious about changing the lighting type as i am having these blotches.... I'm just hoping that i don't have to hunt around for dodgy materials that might be causing these problems.....

[DanielBrew]

Just a thought but do the VRay lights intersect the light fitting or any other geometry at all? I know that VRay plane lights can cause noise if they do.

Ok, I take your point about IES files but if you do want to try the IES route here's a link to a 50w downlighter I have used -
http://catalogo.iguzzini.it/product....nguage=English
And here is the mesh of fitting fitting http://ftp.tskgroup.co.uk/~tsk3d/iGuzzini%20Laser.max

I'm not sure if the fitting has the 50w IES file in it atm but you can download that from the link above.

Dan

[sv]

Cheers Dan!

I'll look into it.

And no - there is no interesection. It's really just a light in a cutout bit of the roof, and a rim at the base of the roof. There are no other elements - even the white colour in the light is generated from the sphere light itself - it's not faked with lightmaterials or anything.

I'll have a look at the IES stuff - nice link man.
And thanks for the model.

[DaForce]

Are you using any raytrace/architectual materials? any falloff maps?

Also any mapping errors or erros at all in the vraylog?

[sv]

Are you using any raytrace/architectual materials?

no - always only vray mats.

any falloff maps?

yep. Probably some; but only for doing fesnel reflections.

Also any mapping errors or erros at all in the vraylog?

no..

I think that the problem lies with the Vray Sphere lights... I'm working on another scene at the moment where i was using the same sphere light setup, but was also having problems, so switched to plane lights at it all seems hunky dory.

To be honest i haven't had time to do some testing, but i think that the problem does lie either with the sphere lights or because of refractive GI caustics as instinct suggested.

I'll post some updates when i get a second to move back onto this project.