Hi i'm facing an issue wich happens in Arnold 4 (alSurface) and 5
(aiStandardsurface)
If i'm creating a shader with metal intensity 1 and a plain directional
light with intensity of 1 it results in specular values of upto 500!
This value decreases by increasing the radius/angle of the light - in my
simple example i had to use an angle of 60 to get the spec values to
something around 1.
If i use a skydomelight the specular intensity values matches the
intensity of the light. Wich is what i would expect.
Why is that?
What can i do to tame the the spec intensity ? Clamping would be my last
option.
thanks for any input
This is because it's relative to the solid angle of the light. A skydome will distribute the values over the whole hemisphere whilst a directional light will contain it within it's angular value.
If you'd capture the value of the sun on a reflective sphere, you'd see exactly the same behaviour.
To work around this you can do multiple things:
- Create a rougher material, pretty much everything in real life has imperfections
- Create a less reflective material, most materials are not nearly as reflective as you'd think in real life - even metals.
- Increase the solidangle of the light
You should avoid clamping at all costs in this situation.