Vray Light Vs MTL Light

[Dariusz Makowski (Dadal)]

Heya

Quick question, I got 200 lights in scene, which way is it better to light it. With VrayLightMTL, or with VrayLightPlane ?

And how would affect the rendering speed if I'd use direct light? (what is it doing anywya? )

No GI, Plain flat render...

[Guest]

I would like to know this too, If you have a large ceiling area with hundreds of inset spots. Are you supposed to put a vray light under each spot, or is it best to have a vraylightmtl?

What advantages/disadvantages are there of both? I find that if I use too many vray lights the render times are very high and the scene is very washed out. But with vraylightmtl, there is not enough illumination in them to fully light a scene, I have tried values of 8-9. Should I go higher?

I read somewhere that too higher values cause artifacts and splotchyness. Is it better to have direct illumination on or off for vraylightmtl?

Thanks,

[Guest]

Also how do you go about actually making the light? it obviously needs to glow. If I make a spot light mesh object, and then convert it to a vray light object. The surface area of that light is no where near big enough to emit the correct amount of light. So i find I have to put another vray plane light under it that is big enough.

At the moment I am creating a mesh object and applying a vray light material to it, and then under a group of say 5 spot lights I am placing a vray plane light. To reduce the amount of lights within my scene. Otherwise as above I would have hundreds of vray lights, one under each mesh object.

[super gnu]

whenever i have to do a scene like this (either an office floor or a big masterplan night shot) i find the vray light material absolutely invaluable. small objects with the light material on dont really work very well, and lead to blotchy images, however if you model the light, add a nice light material to the bulb or tube so it looks good, then add a big -ish polygon below with a nice bright light material on it, set it to invisible to render / reflect and refract and shadow casting, plus recieve GI off, and that way you can have basically an infinite number of lights in the scene.

you need good imap settings to get clean results, but the calc time of this is much less than the rendertime for real area lights.

if they have to be spot lights...well then just use max spots. the vray light isnt really great for spot effects (well actually with the new directional parameter maybe it is.. didnt test really)

turning the direct lighting option on in the light material is useful if you have one specific bit where you need absolute accuracy, but it also defeats the purpose of using the light material, as it will be as slow as a vray light in mesh mode.

if only karba's vrayspeedlight plugin would come out we might have another option:

http://www.chaosgroup.com/forums/vbu...ght=speedlight

[simmsimaging]

whenever i have to do a scene like this (either an office floor or a big masterplan night shot) i find the vray light material absolutely invaluable. small objects with the light material on dont really work very well, and lead to blotchy images, however if you model the light, add a nice light material to the bulb or tube so it looks good, then add a big -ish polygon below with a nice bright light material on it, set it to invisible to render / reflect and refract and shadow casting, plus recieve GI off, and that way you can have basically an infinite number of lights in the scene.

you need good imap settings to get clean results, but the calc time of this is much less than the rendertime for real area lights.

if they have to be spot lights...well then just use max spots. the vray light isnt really great for spot effects (well actually with the new directional parameter maybe it is.. didnt test really)

turning the direct lighting option on in the light material is useful if you have one specific bit where you need absolute accuracy, but it also defeats the purpose of using the light material, as it will be as slow as a vray light in mesh mode.

if only karba's vrayspeedlight plugin would come out we might have another option:

http://www.chaosgroup.com/forums/vbu...ght=speedlight

Nice tip - thanks.

[super gnu]

you have to be a bit creative with your invisible polygons to get a nice result, since if they come too close to other geometry (the cieling for instance, or a column) they still tend to leave a gi shadow of some kind. i never did figure out a combination of setting that made them absolutely invisible to gi, but still able to emit GI light.

anyone figured that one out?

best result ive achieved if the do have to be very close to the cieling is to put another vray lgiht material on teh back face, and adjust the brightness so it cancels out and shadowing caused by the polygon. is a bit fiddly but ive done scenes with 3000+ striplights this way.

[Guest]

Thanks for the help

[tammo]

I always use max spotlights with vray shadows when i have a lot of downlights.
They are instanced, set to vray area shadow and very soft falloff radius.
Very fast rendertimes and no render errors.

[super gnu]

depending in the size of the area shadow setting, the rendertimes with spots should be similar to vray lights with the same size., since they are both doing the same area shadow raytracing... maybe im wrong on that though.

[tammo]

Interesting idea, i have to start a bank interior tomorrow that will be perfect for testing those different setups.

[fAEkE]

Shouldn't vray light with "store with IM map" be a better choise than vray light mat? Isn't it about the same thing, but without the flaws that vray light mat can produce?

[super gnu]

it isnt about the same thing.. its exactly the same thing.. flaws and all..

basically a vraylight with "store with imap" on is the same as a vraylight material.. and a vraylightmaterial with "direct lighting" activated, is the same as a vraylight in mesh mode.