Understanding portal behaviour

[jananton]

Hello All,

I'm puzzled about portal behaviour. Some time ago someone, Radiance I think, mentioned to use portals for my kitchen scene, since there are a lot of windows there... However, I've tried both, with and without portals in place, but the one with portals seems to darken everything outside. A picture says more than a thousand words, so here's what I mean.
The only lighting is a Sunlight obvious outside:

800 X 600 jpg, no portals architectural glass only.

800 x 600 jpg, with portals used

Note how in the second picture the outside porch and lawn seem to be very, very underexposed, what makes me wonder if I'm missing something important here, or is this expected behaviour when using portals...

Using Win XP prof SP2, blender 2.46, Luxrender 12/08/08 CVS

Greetings from cloudy Amsterdam,

Jan

[jeanphi]

Hi,

This is a problem with the current poral implementation: light can only come through portals so if you setup a portal for the inside, the outside won't receive light. You can try to setup a second portal for the outside so that it can also receive light, but in this case you might experience artifacts inside because there will be ovelapping portal areas that won't be taken correctly into account I think (I'd be interested to hear about it though).

Jeanphi

[dyf]

jananton,

this thread might be useful? kind of old though
viewtopic.php?f=16&t=255

cheers

[jananton]

jananton,

this thread might be useful? kind of old though
viewtopic.php?f=16&t=255

cheers

Interesting, allthough a little cought up by time...
All in all it seems portals are usable as their location isn't in view, or any view to the world ouside is not visible. I noticed this when I only used portals in the windows off camera and left the visible porch door as architectural glass only. The result was the same as in the bottom picture. Oh well, architectural glass is it then in this case...

Greetings from overcast Amsterdam,

Jan