how do i use skylight portal?

[little_mikey]

hi all,

how does one use the skylight portal feature
in vray area lights?

i tried creating a planar vray area light, checked
on skylight portal (and had my environment light
in the main rendering dialog turned on)

but when i render, its all darkness.

i'm guessing the skylight portal means what is
sounds like? ie, having the environment light
stream in thru the defined portal?

thanks all

[tammo]

i would like to know that, too.

[paul-G]

you need to switch on GI in render settings
P


Room lit with sklight portal set into opening in ceiling and GI switched on

[586]

Paul, can you post the file so the set up can be examined?

Thanks!

[mauarduz]

portal

Please paul, i get the dark image 2

thanx

mauarduz

[paul-G]

heres the file guys
www.kea.uk.com/portal.max

heres another image using 4 skylight portals

this may not be correct but the way I understand skylight portals is you still need the opening in the geometry ie. the window . You then place the vray light within the aperture and select skylight portal . The vray light then acts as a distribution point for the skylight
P

[tammo]

i dont understand. if there is a hole in the mesh the light from the sky will shine through anyway. so why put a vray light there?

[trixian]

Skylight portal

Think of it more as a lens that focuses more of the environments light in through the opening. You should see a substancial increase in the ammount of light reaching into the room when using portals.

[586]

Paul, thanks!
Trixian - love the Mononoke avatar!

[shytigercp]

skylight portals

How long did that scene take to process the irr. map w/ your vray lights? My interior scenes take extremely longer to process compared to my exterior scenes.

ST

[little_mikey]

you need to switch on GI in render settings
P


Room lit with sklight portal set into opening in ceiling and GI switched on

thanks paul. didn't think abt having an opening still.. i thought
that it wld work like an area light but just with a skylight style
of light distribution.

[janper]

doesn't work

paul-G: I have downloaded your scene. It works pretty good, but I've tried to make the same and my scene deons't work ;(((
I have checked all the settings - really everything, but in my scene it doesn't work.
Couldn't you write step-by-step how to make working skylight potral?

Thx!

[Syclone1]

Janper,

why dont you try looking into www.vray.info or searching the forum? You mite find what your looking for there.

-dave

[Psy]

janper, make sure you have the vray environment on and overriding max's.

[flipside]

With the portal function you can have GI shadows with very low irradiance settings, because the portals really cast shadows, see example:
(rendering takes longer because there is sampling needed for the 'portal light shadows')


Same img with portals turned off and some multipliers turned up to get +-same lighting level in the interior, notice the lack of shadows. Irradiance map settings are set way better here because with the low settings from the previous img the GI is super blurry. Actually I don't know if in real life situation shadows would be more like this image or the previous...



But when using windows with other shapes or curved windows, the portals are quite useless imo.