Shadows VRay sun vs Direct light

[Jiri.Matys]

Hi,

found out that direct light with VRay shadows has much better shadow details then VRay sun (with or without sky, doesnt matter). Why? Both are direct lights.

[Vizioen]

How did you set up your direct light? The distance of the vraysun is calculated as if it's infinitely far away (quote Vlado), a direct light not really, if you would place your light very far away it would produce similar results I suppose. But I might be wrong.

[hermit.crab]

What Vizioen said. I don't think a direct (and accurate) comparison will ever be adequate, since the shadow softness is controlled by different means (Sun size / Area Shadows UVW). Eyeballing it, I'm getting similar results when the Direct Light is far enough and has big enough Area shadows.

[Jiri.Matys]

Yes. But I set the sizes to be pretty equal on both light shadows. But direct light has much more details.

[hermit.crab]

Can you attach the scene so we can take a look?

[Jiri.Matys]

Another test. When you load both pictures in photoshop and compare you can see both shadows has the same size. But direct light has much more details. And it doesnt matter if I make sun little bit bigger or smaller, details are not there.

[^Lele^]

The sun is *not* a directional light (i assume this is what you meant by "direct").
It has a discrete size, so it's a small, very distant area light, producing soft shadows.
It's exactly how it works IRL: look at the shadow from a pole on the ground.

[Jiri.Matys]

It doesnt matter. I compared two lights with the same size. Details are different.

[Vizioen]

It doesnt matter. I compared two lights with the same size. Details are different.

But you compared the vraysun and a directional light? Right?

[^Lele^]

It doesnt matter. I compared two lights with the same size. Details are different.

If you think you should raise a bug report, feel free to do so.

[Jiri.Matys]

If you think you should raise a bug report, feel free to do so.

I dont know. I just like the details in direct light which I cant produce with sun light (which is direct too). With direct light there are really nice circles in the shadows.

[^Lele^]

I'm not sure there is much you can do: the sun is simulated really far away, so it's with near-parallel rays, and the softening will happen chiefly in one direction.
With an area light, even with the same screen size, you will get broader ray angles to the subject, and the blurring will be more circular.

Perhaps You may use a directional light in place of the sun, as the sky map allows for it (although it doesn't carry the clouds' bits yet.)?

[Vizioen]

I'm not sure there is much you can do: the sun is simulated really far away, so it's with near-parallel rays, and the softening will happen chiefly in one direction.
With an area light, even with the same screen size, you will get broader ray angles to the subject, and the blurring will be more circular.

Perhaps You may use a directional light in place of the sun, as the sky map allows for it (although it doesn't carry the clouds' bits yet.)?

He could always align/link the light to the sun, disable the VraySun diffuse and set to invisible and put a VraySky in a dome light set to affect only specular/reflection and disable shadows. That way he can have both, I guess? Save as a template and you're good to go.

[^Lele^]

He could always align/link the light to the sun, disable the VraySun diffuse and set to invisible and put a VraySky in a dome light set to affect only specular/reflection and disable shadows. That way he can have both, I guess? Save as a template and you're good to go.

I don't think in fact he can do anything: if he switched the sun for a direct light, the shadowing would still not be the same, still dependent on an area shape, which however would then be located where the directional light is.
So, you still wouldn't get the near=parallel rays, and the directional blur of the sun.

To sum it up:
directional with area shadows (aligned with the sun, crucially *somewhere* in 3d space where it can be edited):


Sun, notice the largely directional blur as the rays are near parallel, because the *location* of the sun disk is simulated far away:

[Vizioen]

Yeah I'm aware he won't get the same shadowing, but apparently that's what he wanted So if he wants to replace the sun with a directional because he likes the shadows more, than to get clouds and proper reflection from the sky he can work with the above workflow or am I missing something? It's monday after all.