jsmackThanks for the explanation. I'm quite new to the VEX part of light materials. The built-in function you are referring to isYasinHjsmackThat's a bummer. Regardless of the noise issue, how would one implement its light material for Mantra?
Karma lights now include ‘focus’ or directionality controls. Sample distribution is still naive AFAIK though, so you can't make a laser, or even remotely approach laser-focus.
I don't know the math for the pdf of ‘directionality’ used by vray and the like, but the pdf for ggx is a nice gaussian distribution. And there's built in functions for getting the weight in a direction with a given focus exponent, as well as the integral over the pdf so you can normalize the power over the hemisphere. That's all I did when I added it lazily.
sample_hemisphere
and create_pdf
?