Texture-mapped area lights

[vlado]

I was playing with VRayLights a little bit while writing the documentation...
Someone was asking some time ago for the ability to apply texture maps to VRay lights; while this is not possible at the moment, you can fake it - make the light a "skylight portal" and put a self-illuminated plane right behind it. There is no GI in the image below, just one VRayLight.



You can also use skylight portals to help VRay transfer light from one place of the scene to another - for example through small cracks, doors etc.

Best regards,
Vlado

[GoncaloP]

Thats really nice!

Gonçalo

[Nenad]

Hope this is not too much off topic : Usually when I do interiors I always get quicker results with standard invisible VRay lights than with the skylight portals method. Why? What makes the portals slow down the render?

BTW, your image is inspiring!

Regards,

Nenad

[winberg]

I have to admit I almost never use vray lights, I use selfilluminated planes instead.
The rendering hit when using selfilluminating planes are not big, And I find it more flexible to use selfilluminating planes..

-Tom

[Nenad]

(...) And I find it more flexible to use selfilluminating planes (...)

I have to disagree on this. With self illuminated planes, it's easier to get artifacts, plus you need the VRay material wrapper to have sufficient control over the light intensity. Also, VRay lights are far more physically accurate : look at that Vlado's render, no GI, and the illumination is quite realistic already.

Just my opinion of course, maybe you have a better method which you would like to share?

Regards,

Nenad

[winberg]

Ok, I need to say that when I am using selfilluminating planes, they are always quite big, And when I use them I always use them with some kind of texture mapping...

I have never experienced any artifacts using them either..?

The reason for me using this is because of the reflections. The way vray lights are implemented now, you always get "ugly" solid color type reflections, but with my selfilluminating mapped planes I can get more "organic" looking reflections and fine tune the the reflection strenght (rgb level) and illumination seperately...(vraymatwrapper)..

hense the "flexibility"

-Tom

[Nenad]

(...) hense the "flexibility" (...)

... Hence, you convinced me.

Thanks for the tip, I'll try it out.

Regards,

Nenad

[586]

Tom,

Somewhere, way back when, you described how you set up your self illuminating planes (I think you mentioned something about putting a radial gradient map in the diffuse slot or something).

Could you please show us what you do to achieve the effect that you want?

[winberg]

(I think you mentioned something about putting a radial gradient map in the diffuse slot or something).

Thats the one...or you can put an image of your mother in the diffuse slot, whatever does the trick....

Just remember to crank up the rgb level


-Tom

[586]

Thanks, Tom. Much appreciated.

An image of my mom? Now we can add another HDR format: HDR, EXR, MOM

[losbellos]

but how this works actually ? I dont get it. I would think that then I have to use skylight/enviroment light (skylight portal on)to make vraylight emit some light. But it is even possible with a self illuminating plane behind it...
How does vray light know what to do?

[586]

Tom can probably give you a better idea here, but I think the concept is to use a self-illuminating plane with a bitmap in the diffuse slot. Make sure that the RGB output is high and that generate GI for the plane is on. Am I right about that, Tom?

[losbellos]

No, I think he used the map in the self illumination slot.
But my question is, how vray light know that it has to transmit the self illuminted planes light (what is the logic behind). So because we used it with the enviroment for example. Anyway. It works and thats it.