hmmm weird daylight system

[Dave Buckley]

just been doing testing in max 2009 and mental ray

 

trying to light an interior but i seem to think that when using sky portals, changing the mrsun intensity has no effect on the scene whatsoever, other than making the sky portals not as blown out, see the attached images

 

the only difference between the two is that one where the sky portals are really bright has the sun set at 1

 

the other has sun set at 0.2 with a bit of transparency on portals???

 

any thoughts

[novelh]

I thought the sky portal transmitted sky light not sun light. Try increasing the sky intensity.

[Dave Buckley]

sorry yes they do, but i also thought they directed the correct amount of photons through the relevant window, in which case photons come from the sun.

 

but if there is sunlight entering the room through windows, you would assume that decreasing the mulitplier of the sun would have an effect on the whole scene rather than just the intensity of the portals???

 

or have i got mixed up

[Macer]

The MR sky shoots it's own photons (seperate from the sun) and just to confuse things moe the manual states:

NOTE mr Sun and mr Physical Sky can inherit parameters from mr Sky even if the

latter is off.

 

The sky portals gather sky light only, not sun light. I think I read somwhere that sky portals work best when the sun isn't shining through them?

Also make sure that you delete or don't save the FG map between tests, as this will transfer the lighting info.

I hope this helps...

[Justin Hunt]

The portals just get the colour from the mrsky, not intensity or anything else.

 

Think of them as glorified Area lights.

 

jhv

[Macer]

Okay, so the MR sky doesn't shoot photons - but is it like an area light? How is it treated by the render engine? Just curious as to how it works. It shows up as a ray traced light at render time.