Hi,
I have created a scene that has multiple light sources within a pool. The lights are regular corona lights (circle) and are producing VERY sharp shadows across the ceiling (see attached). I have also tried using ies lights but I am getting the same result. To my mind, these shadows should be very diffused as the light source is so far away from the obstruction.
This also occurs with the pool water hidden so that’s not the issue.
Any ideas would be greatly appreciated!
Jamie
That’s very odd, following to see what’s causing this.
Are you using hdri for light? We need more info of scene setup,you can check scene by turning off some elements
My first guess would be that the light size is just too small for the scene. What’s the disc radius and are the scene/system units set up correctly?
Good Luck
Yeah, it looks like this could be actually accurate if the lights are very small.
Hi all,
I am using an HDRI for the external lighting but in a separate test I turned off all but the pool spots so I can confirm it is definitely them causing the sharp shadows.
With regards to the size, this still occurs if I make the lights much larger. It seems to happen irrespective of the size. My scene set up is to scale and the same default ‘starting scene’ that I use in every project. however, I have never seen this before.
As I mentioned before, even using an ies light doesn’t work. My only suspicion is that the lights are excessively bright. Although, regardless of how bright they are, I can’t imagine I should be seeing such sharp shadows…
the radius is 2cm, roughly correct for a small spot light. But if I make the disc 20cm for instance, the error persists.
Judging by the shadows’ directions, it looks like sharp shadows are produced not by the pool lights, but by the ceiling lighting. Did you check that?
yes, I turned off all but the pool lights. I also checked that it wasn’t the mesh tearing as that has been known to happen (when lazily modelling with splines…)
How you made bacground? Did you turn off the light if it’s lightMTL for plane/ Also try to change or turn off hdri, i think it goes from hdri sampling
Can we have the scene? 
(or a stripped version of it, with just the lights and the ceiling)
The background is added in post. I rendered separately with all the lights / light materials removed so I am positive it is the pool lights. I’ll do another test render and attach.
Yes, I’ll upload a lightweight version of the scene shortly.
Hi guys,
I have attached a lightweight version of the scene for you to poke at. please let me know if you find any gremlins…
shadows_test.c4d (1.3 MB)
A very quick look at the scene - raising the light size to 20 cm did indeed soften the shadows considerably. Could then use different lights for the visible ones and the ones casting the illumination.
C4D doesn’t seem to have “real world units” for scale etc. so I am not sure if this plays in to the situation with the lights here or not - the developers would need to say for sure whether this is expected or a bug. Personally, given the distance of the shadows and objects that cast them from the light source, the shadows do seem unexpectedly sharp to me just as a gut reaction, but I can’t say for sure at the moment if this is different from 3ds Max or whether the result is as expected from a “laws of physics” point of view or not.
Oh, so it’s C4D. Beeeeen!
You rang? 
Got the file, I’ll take a look. Without looking at it though, it would seem accurate with the light source being so small. I’ll need to do some tests…
Thanks. It just appears to be far too sharp considering the distance from the objects casting shadows. I’ve done loads of pool scenes of a similar nature in vray and can never recall having this issue.
