Explanation of skylight portal in vray light parameters

[stevesideas]

Ive read the vray docs, but not sure if i still fully understand this feature.

Normally, when doing an interior scene I put vray lights at the window entrances, have a vray sun and environment and then render.
Is this wrong ? Should I have skylight portal ticked ?

[stevesideas]

ok, i just did a test. I had my scene setup without the skylight portal ticked. Renders fine.

So, I tick the skyportal box and also click simple (after reading vlados explanation), and the whole scene goes darker and is almost like the lights are not lighting the scene now.

So i increase the iso in vray physical cam. The scene is now lighter, but it still isnt getting as much light into the interior ?

Is the skylight portal not able to travel through refractive surfaces ? I have glass at all the entrances.

[stevesideas]

Anyone ?

[percydaman]

the skylight portal only magnifies the skylight. itll never give you the same amount of light that a regular vray light will give you. I never use em frankly.

[DaForce]

Now days their best use is around lights that make use of the vraylightmtl, kind of like boxing in the light with skylight portals. It willl help clean up and speed up renders when using vraylightmtl.

[vlado]

The portal light will only get you the same illumination that you would get from the sun/sky light only; it simply helps to propagate the light better. So, if you get a darker rendering with the portals, then your scene would have rendered darker in the first place - in that case you simply have to adjust the camera exposure or the sun/sky brightness.

Best regards,
Vlado

[stevesideas]

ok thanks for the info.