VRayObjectProperties - No GI on other mattes - does not behave as expected - BUG?

[ultrasonic]

Hey Gang,

i found this behaviour some weeks ago,but also found a way to work around it, but it seems that the default setting of "noGIonothermattes" on the VrayObjectProperties Node does not produce shadows when turned of. It's a little difficult to describe, so i attached a file and three images.

Here is the scene without matte objects turned on.


Here is the scene with matte objects turned on and noGIonothermattes OFF.


Here is the scene with matte objects turned on and noGIonothermattes ON - notice the Reflection of the non-shadowed groundplane on the lower right of the sphere


I also attached the .mb file.
noGIonOtherMattes.zip

My question now is if this is the intended behaviour or if it is a bug? If it's intended,the please make "noGIonothermattes" OFF by default.

cheers
Oli

[vlado]

It is the intended behaviour, yes. When "No GI on other mattes" is enabled, GI rays starting from one matte object and hitting another matte object will just see the environment (instead of the actual material on the second matte object).

Best regards,
Vlado

[ultrasonic]

ok...good to know, but i think it would be more user-friendly if the noGIonothermattes would default to OFF
Otherwise every render would break if you split it up into different VOPs and comp them together.
What do you think?

[vlado]

Well, it was off initially but is on because several people requested it

Best regards,
Vlado

[ultrasonic]

ok...i see....so i won't complain...but from a logical point of view it would make more sense to keep it OFF....is there a way for me to influence the default behaviour by changing vray scripts?

[pechart]

Little bit OT, but another thing is, that options like "No...", "Don't use...", "Not for..." are always a little bit confusing imho. In my understanding an option should either be ON or OFF, and not enabled in order to disable something. In Maya that's solved pretty well in the renderstats for example. It's always positive, "Visible in...", "Cast...", "Primary vis. on" etc. You can see what's going on at once that way.
Like I said, OT and just my opinion. But maybe worth considering when implementing new features.

[ultrasonic]

Yep! +1
it's totally confusing....but it think at this state it is impossible to change older attributes. But i would also encourage chaosgroup to keep this in mind when introducing new options on their nodes.