VRayMtlWrapper Not catching shaodws on enclosed enviroments

[sean_brown]

Hello, I am not sure if this is a bug or my mistake but when I used a VRayMtlWrapper with a VRayMtl as the Base on say a polygon plane with a sphere placed on top top of the plane and a vray area light above i am able to catch the shadows with the VRayMtlWrapper options Matte Surface, Shadows and Affect Alpha turned on with Alpha Contribution set to -1. I can see it in Vray Frame Buffer as well when i select Alpha. But as soon as I enclose the environment by either extruding the face of the plane and making an enclosed cube or by manually adding plans the sides and top, i can no longer catch the shadows and only see the sphere in the alpha channel without shadows. Is this a bug or am i missing something?

Thanks

[hermit.crab]

There should be an issue. Are you obscuring the lights in some way? Could you post a screencap and a simple scene?

[sean_brown]

There should be an issue. Are you obscuring the lights in some way? Could you post a screencap and a simple scene?

below are screen caps and a sample scene. Im trying to insert 3D objects into a photo so i need to render just the objects and their shadows that i can lay over on top of the photo.

https://www.dropbox.com/s/3lvzzze79b...adows.zip?dl=0




RGB


Alpha

[Buck]

do the normals on that box perhaps need to be flipped?

[sean_brown]

do the normals on that box perhaps need to be flipped?

the normals were facing outside, so i flipped them and now i can catch the shadows but its created a new problem. i am using the environment sun and sky override in the render settings with a window cut out to light the interior but when i flip the normals, the sun/sky penetrates the cube like its not even there so the everything is lit like its outside. is there a fix for this? If someone could take a look at my file and see how its possible to catch the shadows and not have the outside sun penetrate the entire cube and just come thru the window cut out and catch just the object and shadows to composite on top of a photograph, id appreciate it.

shadowssun.zip

[intercard]

Hello !

try to fix this temporarily separates a face as a separate object, for example the face floor !

hugs

[Buck]

or give the room object thickness.

[sean_brown]

I tried giving the room thickness and also duplicating and detaching the faces as a separate object and the sun light is still penetrating the cube like nothing is there. Is this bug?

[fixeighted]

I think it would be helpful to see the actual image you are trying to insert an object into, but in any case, if I understand the issue correctly then the below info may help.

In my example, I have a floor, a ceiling and 4 walls, one of which has a window cut out. A sphere on the floor and a sun casting shadows through the opening.
If in this example you make the floor, ceiling and the 3 solid walls as matte objects, then the wall with the opening is left as is, though with its properties set to 'invisible to camera'.
This solution allows correct internal matte shadows. It's simple enough to do, though I can post the setup if helpful.

[sean_brown]

I think it would be helpful to see the actual image you are trying to insert an object into, but in any case, if I understand the issue correctly then the below info may help.

In my example, I have a floor, a ceiling and 4 walls, one of which has a window cut out. A sphere on the floor and a sun casting shadows through the opening.
If in this example you make the floor, ceiling and the 3 solid walls as matte objects, then the wall with the opening is left as is, though with its properties set to 'invisible to camera'.
This solution allows correct internal matte shadows. It's simple enough to do, though I can post the setup if helpful.

Yes, please post a setup if you can. Thank you.

[fixeighted]

No problem, here's a link https://www.dropbox.com/s/86iejqcosh...0ROOM.max?dl=0

[sean_brown]

No problem, here's a link https://www.dropbox.com/s/86iejqcosh...0ROOM.max?dl=0

Hi, this is a Max file. Im using Maya. Can you convert it?

[fixeighted]

Oops...apologies, I didn't realise it was a Maya question. I'm afraid I don't use Maya but the process and theory is the same.