matte objects and vray

[dpcaltdcah]

we are trying to render cars and entourage separately from the main file using matte settings and everything works fine...almost.

 

I have the ground and the context set to matte with a contribution of -1 in the vray properties and shadows and affect alpha are checked. when I render a vehicle, in the alpha it's white and its shadow is a nice gray. perfect. except when the vehicle is in the shadow of a context building, it appears in shadow in the render window but the alpha still shows the vehicle casting its own gray shadow which is not right. we have tried everything! help!

[Gus_Rayvus]

What you want to do in one pass I think is impossible, but you could use what you have already and render a shadow pass with no Gi without cars and people and use that as a mask on what you already have. Thus cutting out anywhere that a shadow already exists.

[dpcaltdcah]

do you think it's a vray problem?

it works fine in scanline...

[Mechadus]

I gave up on trying to get it to work that way myself... When I do car-passes, I make EVERYTHING except moving cars, the pavement and any road lines/pavers on the road matte -1.. render as a .tga sequence and overlay on the animation minus any moving cars

[dpcaltdcah]

actually that's what I've got.

but you can see in the alpha that the cars are casting their own shadows whether they're in direct light or in the shadow of a building or something.

 

we've moved on to rendering the cars in the main file, excluding them from the GI and lighting them with independent fill lights for when they're in shadow.

 

but doing them as separate targas was ideal because we have several slower computers in the office and the more geometry we add to the main file, the less they can handle them.

[Mechadus]

actually that's what I've got.

but you can see in the alpha that the cars are casting their own shadows whether they're in direct light or in the shadow of a building or something.

 

we've moved on to rendering the cars in the main file, excluding them from the GI and lighting them with independent fill lights for when they're in shadow.

 

Ahh, I see - I thought you were trying to render the cars seporate from the road... Have you tried un-checking 'shadows' and 'affect alpha'? I always leave them unchecked.

[dpcaltdcah]

yep,

I have tried every possible combination of checked and unchecked.

I attached images so you can see what it looks like...

[Mechadus]

Wow - Well Im stumped. I have tried to replicate that effect, and the only way I could do it was by turning Affect Shadows on for my road in the Vray Object Properties. I asked around the office, and one person had that same problem - he said that he deleted and remade his sun and went away - Max bug maybe?

 

Sorry I cant find an answer for that one

 

 

-Nick

[dpcaltdcah]

well, thanks for trying.

we're going with a different strategy anyway but it drives me nuts when I can't solve things like this.