shadows on a clouded day

[thomthom]

I just noticed something while I was looking out my window. It's a clouded day, 10:45am. And shadows are very soft and barely extends away form the objects.

How would you begin to replicate this in V-Ray?

Would I have to use an HDRI or can the V-Ray sun and sky system be adjusted?

[kwistenbiebel1]

Re: shadows on a clouded day

Increase the 'size multiplier' (environment panel>sky).
A value of 3 could be enough....though you could increase more (20?)

[thomthom]

Re: shadows on a clouded day

I will try that.

The clouds have not begun to break up and there shadows are becoming more distinct and hard edged. I think I'll begin to take photos from the same point in different weather conditions to study the light.

[dcauldwell_cg]

Re: shadows on a clouded day

thomthom

I have tried this, and when you increase the sun size multiplier to say 30, you still end up with sharp shadows close to the item which is casting the shadow.
I think the way to do this is, as you suggest, by using a HDRI in the GI slot. Then if the HDRI has a concentrated spot of light, it will produce a sharper shadow, and if it is diffuse then the shadows should be diffuse.

David

[thomthom]

Re: shadows on a clouded day

I see. I guess I need to play around a bit.

Right now I'm observing that it's quite clouded, shadows under cars is mainly visible right underneath them, with very soft edges.

The shadows from the nearby building is distinct, but softer the further it is away from the wall.

You can't control the direction shadows fall with HDRI, can you?

[dcauldwell_cg]

Re: shadows on a clouded day

thomthom

The penny has just dropped. I don't know why I didn't realise this before, but of course if you horizontally 'rotate' the HDRI image in the envirnment slot then you can position the hotspot where you want! I have just tried it and it works.
Also there are a few free hdri images out there, including a whole set from evermotion, with varying degrees of intensity, so it should just be a case of selecting the one that's appropriate.

David

[TOM_cg]

Re: shadows on a clouded day

Personnaly I would do that by reducing the sunlight effect and boosting the ambient light..

I'll try a quick test and will post it..

[thomthom]

Re: shadows on a clouded day

Did you post a reply to this somewhere?