skylight portal vs vraysky

[Junglejuz]

Here's something I've been wondering about for a while now...

Rendering a generic interior scene. I have a standard set-up with vray plane lights at the windows. Nothing is in the external environment to affect lighting. If I put the scene's vraysky map into the texture slot of the vray light I get a very different result than if I just use it as a skylight portal. It comes out darker and way over-saturated.

Shouldn't the result be the same??? What exactly is going on here?

[mattclayton]

Is that a mapping issue maybe? The skylight portal will take whatever section of the sky is behind it (colour tone etc) where as putting the vraysky on the texture slot will map the entire sky to the area of the plane light??

If you just want a little more light in your interior i'd suggest just using the colour temperature option on the plane light and setting it to 6500-8000 or something depending on lighting conditions....or stick with skylight if that#s working for you.

[crazy homeless guy]

Your results are as expected. The VrayLight set to plane is an actual light with controls, the VrayLight set to plane with skylight portal ticked is designed to amplify the existing skylight in the scene. Essentially they are different types of lights.

Your current light options are....

Plane
- Plane Light
- Skylight Portal
Dome
Sphere
Mesh
Disc

Instead think of it like this...

Plane
SkylightPortal
Dome
Sphere
Mesh
Disc

[Junglejuz]

seems logical to me that putting the vraysky map inside the plane light would make it cast the same light as a portal, unless as mattclayton suggested, it is mapping the entire hemisphere onto a single plane. I am not too concerned with the results, as I can use either method and adjust to taste. I actually think using vraysky map as a light texture with a desaturated colourcorrection on it, and bumping up the intensity gives more realistic looking results than the portal. But that's just my opinion.

What I am more interested in is what exactly is going on here and why they are different results.

[Zdravko.Keremidchiev]

It's normal to get different lighting with those two approaches.
In the case where you set VRaySky map to the light texture slot: you use the full intensity of the sky map to light the scene directly, where the skyportal only uses the intensity from the environment behind it. Which is mostly coming form the VRaySun.

[joconnell]

Just as a query Zdravko, Skylight portal only works with sources in the environment tab or the vray environment slot in the render settings does it? Does it have any benefit to a dome light source?

[Zdravko]

VRaySky is a procedural texture base on the direction of the VRaySun. You can utilize it as you wish but its main purpose is to be used along with VRaySun.
Also I don't see any benefits of using the VRaySky map in VRayDome light.

[joconnell]

No sorry, what I meant was if you use a vray light in skylight portal mode, can that only be used with the environment slot or the vray render dialog environment / global illumination map slot, or will the skylight portal work in a similar way if you're using a dome light as your light source instead?

[Zdravko.Keremidchiev]

It will work similarly both ways.

[joconnell]

Thanks for the clarification