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Rick Davidson
11-18-2006, 09:53 PM
Hi all, having problems getting a white background using HDRI. Have removed visibilty of the HDRI Image but even after putting white into my camera background color, I get a black background render (1)

Also when I try to use Global Illumination or light from the HDRI image, the light blows out (2). Gah. Have tried a few tutorials but they don't seem to cover these.

I don't quite understand why some methods use standard light and others use 0 intensity.. help?

http://www.rickdavidson.com/extra/tests.jpg

YourDaftPunk
11-19-2006, 04:47 AM
There is more than one way I have found. Try this though:

1) Create the HDR through IBL in the render settings and turn off Primary Visibility.
2) With your camera, leave the background color black. Create an image plane instead.
3) Set Type to Texture and create a white ramp as the texture.
4) Render and Enjoy!

-shawn

ghostlake114
11-19-2006, 04:54 AM
:)
You have the alfa channel now, and do everything with bg, even change it into a reference image

YourDaftPunk
11-19-2006, 04:55 AM
The other way is to create a mental ray environment shader. Choose mib_lookup_background with a white texture.

Edit: Nope! Doesn't work as expected. I think I actually did something with two single sided poly spheres. Stick to the image plane for ease.

Rick Davidson
11-20-2006, 12:18 AM
Ah great thanks guys, I'll give it a go :)

Ash-Man
11-20-2006, 02:53 PM
IBL node is conceded an environment node , so it will take over whatever you put there

Another way is using render layers

Create 2 render layers with the IBL

In the IBL att editor change the type from file to texture (make it white)and override it for this layer

So now you will get 2 render layers ONE with IBL > HDRI

The other is IBL > white

You can either composite them in Maya or in a separate package

Rick Davidson
11-20-2006, 11:09 PM
So many ways to skin a cat with Maya huh... :) Thanks ashaiad, will try that out too. How would you composite it in Maya?

Ash-Man
11-21-2006, 04:42 PM
in the render layer channel , ther is an option to either "render all layers" maya will put all the layers together for you in one image

you can watch my video tutorial about render layers
cheers

Rick Davidson
11-21-2006, 07:16 PM
That's a brilliant tutorial Ash, thanks! I'll def be using it on this project. The PSD layers option is great :) What would you render the files out as for a TV commercial? BMPs? I'll be taking them into After Effects for compositing.

cpan
11-22-2006, 12:28 PM
you can allways plug ctrl_rays into ibl.texture and make the Eye rays see the background white while the FG rays, Reflection/Refraction Rays etc see the background as your (hdr) texture.

get ctrl_rays mentalray shader from http://mymentalray.com
cya

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