Beer glass scene creation
This course contains a little bit of everything with modeling, UVing, texturing and dynamics in Maya, as well as compositing multilayered EXR's in Photoshop.
# 1 26-10-2014 , 02:26 PM
MrSandman's Avatar
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Use Background - Shadow is too light

I use Maya to make icons, and I've been trying on and off for quite some time to make the "Use Background" shader work as I like.

The end result should be a icon which is a transparent PNG file where the shadow is projected in a supposed ground plane, but is transparent, enter "Use Background", right?

It works, but not as I'd like. I get a shadow, but it's way too light, and not only that, it's also not black, but rather colored grey, which is wrong. See the images I've attached. On the one with white background, you can see how the background on the "ground" is a lot lighter than the shadow on the other objects in the scene. And in the image on a red background, you can see how the shadow isn't realistically "black" either. Not looking for pure black here, but the object appears to cast a white shadow!

I'm using Raytracing and the settings for the Use Background shader is:
Specular color: black
Reflectivity: 0
Reflection limit: 0
Shadow Mask: 1
Matte Opacity mode: Opacity Gain
Matte Opacity: 1

Any ideas?

Attached Images

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# 2 26-10-2014 , 04:45 PM
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What lighting and shadow setup are you using and how are you compiling (photoshop?),,,,,,,,dave




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# 3 26-10-2014 , 04:52 PM
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What lighting and shadow setup are you using and how are you compiling (photoshop?),,,,,,,,dave

Lighting is from two point lights, with the upper one with raytracing shadows.

Attached Thumbnails

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# 4 26-10-2014 , 05:42 PM
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To get crisper shadows you need to turn down light radius to some thing like .3 and shadow rays to say 5 and see how you get on................dave

Also see this tutorial (I think by Jay) so you can just get the shadows for the bachground

https://simplymaya.com/forum/showthread.php?t=34936




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Last edited by daverave; 26-10-2014 at 05:45 PM.
# 5 27-10-2014 , 08:07 AM
MrSandman's Avatar
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Join Date: Jul 2007
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To get crisper shadows you need to turn down light radius to some thing like .3 and shadow rays to say 5 and see how you get on................dave

Also see this tutorial (I think by Jay) so you can just get the shadows for the bachground

https://simplymaya.com/forum/showthread.php?t=34936

Sorry mate, you're misunderstanding me. It's not the "blurriness" of the shadows I'm interested in, they're blurry the way I like it. It's the fact that on the Use Background object, they're way too light, and when compositing the image on something else, the shadows look white, not black.

In the video tutorial above, his shadows are pitch black, but the difference is that Maya is then rendering on an image plane, and I am rendering to transparency... Not sure whether that makes a difference. I tried changing my lighting to directional light like he used, but no change.

If you look at my images again, you'll see that the shadows are darker on the newspaper than they are on the ground. That's the difference I'm talking about.


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# 6 27-10-2014 , 08:11 AM
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Solved it!

My deepest apologies - the problem was that in order for me to see the resulting icon correctly in the render view, I had set the camera background to white, which means the shadow rendered on a white surface, making them too light and also not black, setting the background to black solved the problem. Thought I'd share if anyone has the same problem!


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Sandman[.net]
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