IES lights

[evilmaul]

hi there,

I was wondering about this new light type and if this thing that i noticed its related to the fact that they are basically point lights. (I did record a qt video to show this that I am trying to say but not sure how to upload it).  Basically if I rotate the light we can see the lighting changing according to the new direction but the shadow cast by objs in the scene stays the same. In order to make the shadow change I do need to move the light source (and possibly rotate afterwards).  I guess what it makes it to look even stranges is the fact that once the obj is assegned a IES profile and therefore the icon changes to the actual light profile, if u rotate that profile, visually speaking, you would assume that the shadows would change accordingly to the lighting.
Another thing  , and again, this is related to the nature of IES, the shadows themselves, by definition 'hard', should no matter what still have some sort of softness parameter...hard shadows unfortunately are not very believable.

cheers,
M

[DriesV]

As far as I know, IES light shadows are hard in pretty much all renderers.
Vray f.i. uses trickery (shadow radius...) to soften point light shadows.

I do wonder, though, is there information within the IES profile to determine the shadow softness of a particular light source?

Dries

[PhilippeV8]

Yes, I don't like 100% hard shadows either.  A light source is never 0.1 mm large, so light is never realy coming from a dot.  Control over the softness of the shadow edge or the size of the light source would be great.

[DriesV]

I think the question really is:
How can you make it happen without trickery (ignoring the physics of lighting)?
I think an IES light cannot consider both the IES profile and the shape/size of the geometry to which it is applied.

Dries