light portal is what?

[Syllogism]

Hey All

What is this light portal thing? Is there an explanation out there somewhere telling you what it is and how to use it?


Wouter

[flipside]

light portal is what?

It is used for interior renders only, where environment light should enter the room. You would typically place it inside a window opening. It siply captures environment light (skylight) on one side, and throws it out on the other side. Result is that you will have a bit more light coming into your room, plus you can let it generate raytraced shadows to get more detail in your shadows.

It isn't used that much however. You can also use a normal light instead in your window opening, but the portal automatically catches enviro light so this is more correct than putting a normal light in it and giving it a random multiplier value.

[Syllogism]

thanks for the answer,

very enlightening. haha.

[siggi40]

Re: light portal is what?

Where is the light portal, I mean how can i put it into my scene i cant find in the menus

[dalomar_cg]

Re: light portal is what?

You'll have to add a rectangular light first. Its the first parameter under the light options. Keep in mind that in light portal mode the color and intensity doesn't do anything, since the light takes those values from the environment behind it.

[Micha_cg]

Re: light portal is what?

And you can use it to focus the GI sampling at emitter materials, for example around an light bulb object with emitter material - create area lights (in portal mode) in order of a box around the object.

[Micha_cg]

Re: light portal is what?

... I forget: most you don't need the light portal. I don't remember the last need of LP for my projects. In my standard mode LC+IM the LP makes, that the images is slower rendered and noisier. Often it helps to increase the IM subdivs (for example at 99 ... 200).