matte object - how can it be used for rendering moving objects for animations ?

[eligiusz]

Im trying to render moving objects seperatly by turning all of the 'still' objects in the scene to matte objects but i have some problems with shadows. I prepared some simple scene to show what i mean....

here is how it looks like :


and how it renders:


As You can see the big box drops a shadow onto the torus and it affects its diffuse but it doesnt have any effect on the shadow the torus drops and i wonder if it should be that way ? How can it be fixed ?

Its pretty important because if You have for example a moving car and it goes into the shadow of the tree it still drops a shadow from the sun.

(im using vray 2.40.03)

[tashko.zashev]

Hi,

Can you try to uncheck "No GI on other mattes" option for the matte objects. It think this should help in this case.

[eligiusz]

hey thanks for the reply... Yes i was trying that out but then i have the shadow info from that object witch i actually dont want.


I will try to explain what im doing... i have couple of moving objects and the rest is STILL
1. I delete the moving objects and render the still ones with flythrough for LC and multiframe incremental for Irradience map
2. I set the matte object option for all the 'still' objects in the scene , import the moving objects and render with Irrandience map for animation (prepass & rendering)
3. Composite the two and there is no flickering what so ever and its faster and im happy (almost)

So If i uncheck that option 'no gi on other mattes' i will get doubling of the shadows and GI information when i composite.
I hope I explained it better now

[tashko.zashev]

Hi again,

Thank you for your posting more details about this issue.
If i understand you correct, you want to remove the sun shadows in the area where it intersects with the one from the big box, in order to avoid double shadow casting in compositing?

[eligiusz]

Yes, this is how it would look like...


If the red line shows the shadow from the box then inside of it the torus should not drop the shadow from the sun.

[eligiusz]

Hi, Ive managed to think of a different way to achive what i want... ita bit more work... I put a vray material override for moving object so it drops a shadow but is invisible(opacity)... its also invisible to GI so its only effect is droping the shadow from the sun. When i render only moving object i turn off the 'cast shadows' so it only calculates the GI. Easy peasy

[tashko.zashev]

Hi,

Glad to hear that you have found a way to achieve a working solution for this case.
In my opinion there is no a direct option to achieve this effect for the matte object shadows. So probably it requires more work at the post-production.