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Question related to DOF

Posted: Wed Jul 24, 2019 9:14 am
by luxfuchs
Hello all,

I am currently simulating a water drop on a surface.
To get an accurate result, I tried to use the built-in DOF with realistic camera values.
To my surprise, activating the DOF showed me reflections of lights that did not show up before.
From my understanding this should not be possible since DOF is only a camera effect and should not change the path of the light, thus should not show reflections that were not there before.

I used Bidir + Metropolis.

I am wondering if my physical understanding is wrong here or what is going on, any input is welcomed.
Thanks,
luxfuchs

Re: Question related to DOF

Posted: Wed Jul 24, 2019 9:24 am
by Dade
luxfuchs wrote: Wed Jul 24, 2019 9:14 am From my understanding this should not be possible since DOF is only a camera effect and should not change the path of the light, thus should not show reflections that were not there before.
This is not really correct: many materials have view dependent properties and DOF affects eye rays. So a change in incoming ray directions (i.e. eye rays) will affect the the material outgoing ray directions and how/where they hit the light sources.

For instance, you statement is true for matte but not for glass or mirror material.