15
$\begingroup$

I've heard a lot about this 'cool' feature in the next release and I wonder what it is. Any infos?

$\endgroup$
2
  • 3
    $\begingroup$ Light Portals are objects that help Cycles render interior scenes (incomming light) more efficiently. $\endgroup$
    – p2or
    Jun 26, 2015 at 11:23
  • 2
    $\begingroup$ recommended: blender.stackexchange.com/a/33154/3710 $\endgroup$
    – p2or
    Jun 29, 2015 at 9:11

3 Answers 3

11
$\begingroup$

Light portals are a method of reducing noise, which, as you already noted, is new in 2.75.

Light portals help to remove noise by guiding rays from the environment through the openings where a portal is positioned. Because of the fact that they are designed for openings, they are most useful for architectural scenes.

It acts a bit like setting a light or HDR set to multiple importance.

Sampling is also slower when using portals, but usually the reduced noise more than makes up for the time lost while sampling.

To add a light portal, add an area lamp, and position it in the center of an opening. Make sure that it is facing inside. Then, using the lamp settings, change the dimensions of the lamp to fit the opening, and check the portal checkbox

enter image description here

enter image description here

Here are two comparisons from the docs:

enter image description here

enter image description here

$\endgroup$
0
9
$\begingroup$

It is a plane that defines where the most of environment light will come into the scene, so the renderer can sample light more efficiently.

Usually speeds up indoor rendering. The sample takes longer time but the noise will clear out after fewer samples.

Multiple light portals can be used, but it's only good to place them on the main light sources - like windows (or a TV if it's the main source of light in a night scene).

$\endgroup$
1
  • 1
    $\begingroup$ Light portals aren't for all light, but instead, only for environment light. $\endgroup$ Jul 13, 2015 at 5:09
3
$\begingroup$

(Light) Portal is a setting for Area Lamps that helps sample enviroment light more efficiently in Cycles. It's useful for interiors where enviroment light is coming through a window or door. You can get a clean image with less samples, although each sample takes a little more to render. The end result is a small to mid speed increase, it depends on your scene.

In my experience they also seem to change the lighting subtly, giving it more of a "direction".

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .