PDA

View Full Version : using IBL with matteshadow for floor?


Hakushinkan
07-25-2010, 02:39 PM
Hey all,

I've been trying to render a scene with image based lighting.
The image I'm using, when viewed from within the sphere, gives the feel of an open field.

I'm placing my car in the middle of the sphere, and I hit render. Everything looks great, except for a few things:

1. The background seems too dark (or sometimes too light), and not very realistic.
2. The car doesnt drop shadow on the floor, which destroys the realism.

I know the matteshadow mental ray node can do the trick for the shadow, but I don't know what to connect to the "background" property of it for it to seem transparent. I know that when using the cameramap node, I can connect that one to the background property of the matteshadow, but when it comes to IBL I don't know what to do.

Any advice would be appreciated.

Thanks!

Dangertaz
07-25-2010, 06:59 PM
One work-around would be use mib_lookup_spherical and connect that to your camera's Mental Ray environment slot. Your scene should be lit and reflections should be generated as if it were using IBL.

Then plug the same lookup_sphereical node in your mip_matteshadow's background channel.

Hakushinkan
07-25-2010, 07:37 PM
One work-around would be use mib_lookup_spherical and connect that to your camera's Mental Ray environment slot. Your scene should be lit and reflections should be generated as if it were using IBL.

Then plug the same lookup_sphereical node in your mip_matteshadow's background channel.

Thanks for the reply.

I've been getting much better results using the IBL for lighting.

I found a possible workaround, but it blocks the freedom of camera moves and such.
I use the IBL to create a mirrorball and a background image of the environment, and then I use the rayswitch environment to place my car in there.

It's kinda going around the shortest route, but it's the only way I can be in control of my scene right now. It's just weird that you can't connect the IBL node to the matteshadow node... I guess it's one of those mentalray-in-maya problems. =\

Dangertaz
07-25-2010, 10:54 PM
I just ran a quick test and the only difference I can find between the IBL and the mib_ lookup_spherical is the initial orientation. They are just rotated differently but that seems to be about it.

Just out of curiosity, what are the differences for you?

Hakushinkan
07-25-2010, 11:19 PM
I just ran a quick test and the only difference I can find between the IBL and the mib_ lookup_spherical is the initial orientation. They are just rotated differently but that seems to be about it.

Just out of curiosity, what are the differences for you?

I guess I find the spherical more complex to use and the results are a bit less realistic.
Maybe I'm using it wrong?

Edit:
I just rechecked it. I guess my memory was misleading me, maybe I confused it with something else.
But I do still have a slight problem with it. I can't control the color gain of the texture node. Is there any work around for this?

Thanks by the way.

CGTalk Moderation
07-25-2010, 11:19 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.