# Size of infinite light (as sun reflexion over water)

• Hello

Is there any possibility to set the size of the infintite light to make a sunset reflexing over water. In my case the sun reflexion is to big relativ to my sunset skydome picturte. And there is no effect if I change the scale of the infinite light.

• "too big" is vague. I can guess you're using the wrong roughness value on the water but I can't be sure without seeing your shader and your render.

If your reflection roughness is near zero, the size of the reflection cannot be bigger than the original.

• @bagginsbill

Thank you. It's better with a far away constant light spot. But you think the infinite light should also change the size with scaling?

this is with infinite light

this is with a var away spot light

this is tge waterplane

• What if you make your waterplane not a plane but spherical to earth radius?

Over the area of your sun highlight, the difference between a sphere and a flat plane can be just enough to make the difference. Differences are amplified by the reflection.

• I haven't responded because I feel like I need to experiment before giving advice and I haven't had the time.

I am surprised to see the narrower reflection with the spotlight.

I do not think that adjusting scale on an infinite light would affect anything. It is not a 3-dimensional light source, but rather it models a light source infinitely far away, which is to say having no visible dimension whatsoever. (Even our real sun occupies 1/2 degree and is not accurately modeled by infinite light)

An infinite light is just an angle from which light "appears" out of nowhere. Besides choosing that angle, you can't do much to alter the direction from which it appears, and certainly not with a scale dial since it has no size to adjust.

Interestingly we DO have ability to alter the "apparent" size of the infinite light with respect to shadows. It is curious that the shadow blur radius (which is actually an angle) doesn't alter both reflections and shadows. Or maybe it does.

But in any case, that blur radius can only make the apparent size BIGGER than 0, not smaller than 0. I have no explanation at the moment.

• Did some experimenting with a simpler setup than your world. Found something interesting.

Can you try: Change your GlossyBsdf Roughness to .0001 (instead of the .001 you had in screen shot).

• Regarding:
@bagginsbill said in Size of infinite light (as sun reflexion over water):

It is curious that the shadow blur radius (which is actually an angle) doesn't alter both reflections and shadows. Or maybe it does.

Through further experiments I have verified that the Shadow Blur Radius not only influences the shadow size, but also the apparent reflection (or refraction) size of the infinite light source. (Only in SuperFly of course - FireFly doesn't reflect or refract direct light sources at all.)

• @bagginsbill

Thank you very much. Change the GlossyBsdf Roughness to .0001 (instead of the .001 you had in screen shot) solved the problem

this is now with infinite light