Secondary bounce multiplier

[chrisj]

Hi,

Just trying to find out why the secondary bounce multiplier is limited to 1.0
as I'm having trouble with a dark interior.

thanks,
c

[trixian]

Most likely so light doesn't increase energy as it bounces around.
Try using portals and / or photons to get more light in, or if you're using 1.45.70 then try with lightmaps for the secondary bounces as well.

[tom schuelke]

Well the diffuse light distribution in vray gets calculated by the rgb value of the material surfaces.

if you use 1 in first and also secoundary bounces, this is the best choise to get accurate lightdistribution in vray compared to realworld.

of course some times you also could use more reflected energy like you sometimes like to do with the standart radiosity override material in max radiosity.

but if you want this you still have the option todo so by using the vray object settings in the Renderdialog of vray, which gives you the posibillity to give single objects a higher value as usual. so light gets reflected stronger as in realworld.

you have to pay attention because this can cause bright materials to produce a sort of "lightexplosion" in bright areas.

also you do have several opttions in exposure control.

So usualy start with 1 in first and secoundary bounce, after this use exposure possibillitys and only at last object override.

hope this helps you

Tom

[doan]

Another usefull setting to play with, is the "color mapping". You can have more control on the darkness or brightness of your scene. I always use it works really fine for me.
Another thing which is not VRay feature, but helpfull, is the "Gama" correction in Max general parameter. Tick it and play with the values...........I hope that help

[cpnichols]

Everyone has given some good explanations. Let me expain to you "historically" why that is. A long time ago, Vray had the ability to use what ever you want for your secondary bounces. The problem is that it does not make any sense. Because it means that light will get brighter as it bounces around. Like a basket ball that bounces higher with every bounce. You need light to loose energy as it hits a serface. Also, it would tend to produce really bad light artifacts.

So they limited the secondary to 1, and added the color mapping section. This is like an exposure control. For interior scenes you may want to use Exponential type and play with the values of the bright/dark multipier