matte problem pt2 [urgent]

[pinpan71]

thats what i want:


box and plane rendered and used as a background:


thats what i get:


so why, if the big box is still there (as a matte), it does not block the sunlight hitting the smaller box and therefor get rid of the "double shadow" on the groundplane?

is there a setting to do just that? i could not find it. do i have to use render elements vraymatte shadow and play composit math?

the problem looks very much like what da_elf posted some time ago. but he was referring to videofootage with rendered images. so maybe there is an easy solution.

did i mention i am approaching my deadline in big steps? so i need a fast answer (vlado?)

[vlado]

Go to the V-Ray setting dialog for the big box, and uncheck the option "No GI on other mattes".

Best regards,
Vlado

[pinpan71]

i tried that before.
thats what i got:




the background image gets much darker than the original in the shadow areas...

[vlado]

Ok; which are actually the matte objects in your scene?

Best regards,
Vlado

[pinpan71]

here is an example in a real scene:

1.) matte shadows off


2.) matte shadows on, no gi on ohter mattes off


3.) matte shadows on, no gi on ohter mattes on

[pinpan71]

the big box and the ground are matte,
the small box represents moving objects (peepz, cars)

[RErender]

If you save out separate shadow passes you can subtract the base shadow from the secondary passes shadows.

[pinpan71]

If you save out separate shadow passes you can subtract the base shadow from the secondary passes shadows.

i am aware of this solution and to be honest, i am really a bad "compositeur".
what i was not sure about is, which shadow pass is the right one. my guess was vray matte shadow.

and many sequences are already calculated without the shadow passes.

time is quite critical at this point so i was hoping for a one-click solution.

[^Lele^]

Hope comes for free, solutions oftentimes do not.
Mask away by hand (easy enough as the shadow is a regular geometric polygon), and you'll be sorted.

[pinpan71]

Hope comes for free, solutions oftentimes do not.
Mask away by hand (easy enough as the shadow is a regular geometric polygon), and you'll be sorted.

easier said than done...
lots of cameras, lots of frames, lots of complicated shadows. so the good old manual approach is a no go solution...but thanks for your words.

[^Lele^]

Sorry for the *slight* sarcasm in my last reply, but you can't render (lots of frames with no shadow passes), you can't comp (not a good "compositeur"), you cannot re-render (time is quite critical), you'd rather not do the hand work.
What kind of solution is left there?
To hope?
Me, I'm left with little that could be of any help, bar that I'd start masking away in earnest.

[pinpan71]

Sorry for the *slight* sarcasm in my last reply, but you can't render (lots of frames with no shadow passes), you can't comp (not a good "compositeur"), you cannot re-render (time is quite critical), you'd rather not do the hand work.
What kind of solution is left there?
To hope?
Me, I'm left with little that could be of any help, bar that I'd start masking away in earnest.

no prob lele, i thought there is an easy solution for this. i am confident that i will work it out.
i just feel that in the sense that how matte should work it is than not 100% complete.

the setup with one big and one small box shows a weak point. an option for a matte to block out the shadow of the small box where the light onto the small box is blocked by the big box seems logical and would be usefull for me. but maybe thats just to complicated or utterly useless for everyone else.

anyway, i will go the way of the passes and learn comping.

regarding the critical time i can only blame the client (and my ambitious efforts).
all together its 5 minutes of animation with a long storyboard and lots of different shots
in different -some heavy- scenery. the time from storyboard to dvd is 2 month and i have not much left.

i still did not find my perfect way how to deal with lots of animated elements like people and
cars etc. this time its just so much more complex compared to the typical archviz stuff i usually have to deal with. i'd wish i had a big farm and could bruteforce away.

hope everything works out in the end.

[^Lele^]

Well, the stretching thin in a project is quite common.
In fact, that's what long hours, and post work come in handy
Best of luck with sorting it out the bits not working!