is physical sun emmitting "sky" light

[DaForce]

http://www.spot3d.com/vray/help/150R1/

[Daniele_ve]

there's no light in the shadows of a scene with only a Vraysun

It's not true, there's light, but is much more dark than what you can get with your eyes. I think it depend on your exposure, gamma, and maybe a little bit simplified model of the sky light.

There's a big difference in the amount of light in shadows between using GI and using a dome light.

I don't think so, if you use a dome you can just have sharpener shadows than with a low IM (and sometimes also with a high IM)

[Infrared digital]

What I am struggling to understand is - how do I brighten the shadows in a scene using a vray sun and sky ? If the vray sky has hdri like abilities - how are they affected ?

I appreciate it is a combination of parameters but when the shadows are brightened with the color mapping or increasing the camera f-stop the scene gets blown out.

Have also used a dome light but render times go bananas.

[vlado]

What I am struggling to understand is - how do I brighten the shadows in a scene using a vray sun and sky ? If the vray sky has hdri like abilities - how are they affected ?

I appreciate it is a combination of parameters but when the shadows are brightened with the color mapping or increasing the camera f-stop the scene gets blown out.

Have also used a dome light but render times go bananas.

You could try making your materials slightly brighter. That would cause them to bounce more light into the shadow areas.

Best regards,
Vlado

[Infrared digital]

I find that on the lit side of the building, I am darkening the materials but at the same time I am trying to brighten the same material on the shadowed side.

[jujubee]

Yes - I found the same thing. I think it's because you have to adjust your camera like you would in the 'real-world', assuming your digital camera isn't using automatic exposure.

Other way to do it is to raise your color mapping bright multiplier.

[Da_elf]

why not leave the sun at its normal brightness but raise the brightness of the sky?

[jujubee]

It's hard to describe - there's a weird variance that Infrared is describing and changing sky brightness alters the other angles. I'm not sure if it's related to LWF and the sun/sky system on the darker side of objects, but I've seen it happen which makes it a pain to constantly have to readjust settings from different angles.

I was hoping that the 'Video Camera' setting would take care of this inconsistency.

I also use Linear Workflow - not sure if Infrared does nor if it's isolated to this method.

[jow]

One semi fix i found for this problem is to over-expose the camera them use reinhard mapping and drop the burn value to suit.
Similar to what you said Juju about tweaking the colour mapping,
only prob with it, you lose abit of contrast in the image. But hey thats the idea i guess...

[DaForce]

Elf, so how do you raise the brightness of the sky?

[CCS]

Output map

[jujubee]

Yeah - but then it effects the other angles.

[CCS]

Right. I was just answering DaForce.

I was sold on the sun/sky (and I still am for exteriors - usually) thru the 1.4x releases, but I'm now tending to go back to the old methods. I suppose the whole sun/sky/camera thing appeals to people who want to just "drop it in and hit render", but that's not me. After all, we jack up reflections in a material, or exaggerate bump, or whatever to get an effect we're looking for - even when it is not physically exact. Same goes for lighting often. I may want light streaming in thru that window, even though at my latitude and with the house's orientation it may never happen. I'm doing a dusk render right now and using a sky much oranger than would probably typically happen - all because that's what the client wants.

If I wanted a single, "physically correct", "unbiased" solution with a big green RENDER button, I'd buy a certain package... (can't remember the name). But I rarely get a job like that. Clients want specific things, so I need to have that control that I get with vray.

That doesn't help you with your sun/sky tho. If there is a way to accomplish what you're after, I'd be curious too. But I suspect there is not. If you're using "physically correct", that *has* to mean that it is mostly unalterable. So to get a different look you have to go changing materials. Or, render a few different exposures then mask and composite them.

[jujubee]

I'm currently testing a dusk scene as well. I'm finding the physical camera set to 'video camera' is working a lot better than changing the angle on the still ones.