Monday, January 20, 2014

Solid Angle Maya to Arnold v0.25.2

I kind of rediscovered SolidAngles's Arnold renderer yesterday and have been playing around with it to get some good results that I can export to Nuke for compositing. However, I've been having such a blast I spent more time on arranging shaders than actually getting something ready for compositing.

To achieve some more fundamental knowledge about the program I decided to create some simple shaders and from that a scene. Unfortunately none of the shaders from the SolidAngle support side worked so I figured out most shaders myself with some help from the support file. Next to this I figured it would be fun to create a bulb shader that I would apply to some cubes that I thew around the scene using drag, gravity and newton field simulations. Can't even express how much fun that was, though the gravity field simulation didn't always work well with more than 50 objects. Below is an image of the scene I quickly assembled. From left to right, top to bottom, the shaders are: thin plastic - car paint - ceramic - chrome - clay - glass - bulb - metallic - gold - wood - skin - matte plastic

Shaders rendered in Arnold

When I finished this I found out I couldn't make use of the batch render option box using the Arnold renderer which I found odd since I could circumvent the problem by not clicking the option box but directly rendering the images. I still haven't figured it out entirely but I guess it has to do with how Arnold deals with outputting an image.

After this I creating a rim shader that corresponded with the facing of the camera. Below is an image of what it looks like. What it comes down to is a SampleInfo node sending it's facing ratio to a Clamp node's InputR (or G or B; whatever you want but keep using it). The Clamp node sends that its OutputR to both the vCoord of the Ramp node and the Blender input of the BlendColors node. This way every part of the mesh that is facing the camera directly gets multiplied by 1 and will receive the top color in the Ramp node (v=1). The parts of the mesh that are facing away of the camera will get multiplied by 0 and will receive the bottom color in the Ramp node (v=0). Then the Output of the BlendColors node connects to the Color input of the aiStandard shader. Voilà‎.

Rim shader

I decided to use this rim shader on my Red Skull model because it has some nice definition in the normal map. I played with some light settings until I found something I was happy with and rendered it at a 4k resolution just because I had never done it before. I decided to go for a double three light setup as I wasn't able to light the head the way I wanted with just the three lights. So now it has two back lights, two key lights and two fill lights; all varying in color, saturation, intensity and exposure.

Light setup. The small planes are the lights for the head.

Arnold rim light render.

This was fun. Tomorrow renderfarm and compositing.

Kind regards
Pim

8 comments:

  1. Nice work!
    I have some problem with this shader in maya 2016 whit arnold
    1.2.5.0
    Clamp node it's plugged into blendcolor1 and ramp into color 2?

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    1. Thanks for the comment and yes, I think that is correct. Might as well call it a fake fresnel. :)

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    2. Sorry but my rim not work
      can you post the exact connetion for all nodes?
      and in pamp nodes how may color you have?
      thanks

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    3. Hey Andrea, I've set it up slightly more straightforward. http://tinyurl.com/hm8lrqc . Sampler Info > Ramp > Gamma Correct > Shader. Have fun with it!

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  2. You hane try wuth mtoa shade network with blend color and clamp?

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    Replies
    1. I did, but couldn't get the same result unfortunately. The method above gives practically the same results.

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  3. how do i connect clamp to blend color?to the color 1 or color 2 or both?

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