CompTips_Mask&Zdepth

1. how to get a mask for gus/ ground/ or whatever object u wanna mask out:

<1>.save your lighting file as a other one.
for example: i wanna a mask for gus in shot9, so i saved out my lighting file as other file called 'shot9_mask'.
<2>.create slim shaders with diffuse color of white or black. have the object u wanna mask out attached with color different than other objects.
Remove all the lights u already have, and create a new RendermanEnvLight with color: white;  intensity: 1.0; sample: 512, max v: 2.0.
for example: in shot 9 I wanna mask out gus. so I give him a black color, other set to white color in shader. and then this is my render:

IMPORTANT tips for the B&W slim surface u used in this file:
(1).u need to have the correct displacement attachment to the object. Other wise the mask u render out won't match the outline of your object in the beauty pass. I have already make the some of the surface shader on gus so u guys don't need to remake it. it's in assets/lights/12.0_lights/12.0_lights.proj/slim/palettes/shot12SnowAndBg.splt.
you can find those shaders by open your slim, and File/Open Palette. then open the file above, u will see some black surface shaders for different parts of gus in that palette.
Ask me if u dont know which one is supposed to be attached to which object (u guys have my number right~? lol)

(2) about the snow ground. first make sure u have the effect on it. second, when u make white surface shader for it. make sure change the ' object size' of ur slim shade to 200. otherwise it won't get the correct displacement.


<3>After u have the mask, then u can put gus and env in different render layer, which will also help speed up the render. and Then comp them together. like this:

<4>.If u need to create Zdepth pass for comp atmosphere effect of DOF. I have a way to cheat it.
save your mask file as another one call. 'XXX_Zdepth.ma' (Opppps, so many files >_<)
and then:
(1). connect all the diffuse color of all you surface shader to this mixcolor node: assets/lights/09.0_lights/mixColor_forZdepth.slim (the folder is really messy right now, sorry about that...). and in the SL_box, u can the value of float d to control how far it face into black.
(2). give your sky plane a black shader.
(3). in your renderman control, create a output pass called : 'DiffuseColor'. set it to TIFF. (that's the frame u want for your Zdepth render)

here is an example for shot9's Zdepth pass (I only render the Depth pass for my Env, cuz gus will be in focus all the time)

<5>.Final Comp with another fog layer in front of everything, together with LightWrap & EdgeBlur:

Notes before rendering

• Make sure Ray Traced motion blur is unchecked (under Render Settings>Features)
• Add these RenderMan attributes to cliff geometry:
• Subdiv Scheme
• Trace Bias: 0.1
• Trace Displacement: All

Passes for Rendering

Passes

• Beauty
• Ambient Occlusion
• Z-depth
• Any effects necessary for shot

Masks (Siran will update us on how to do this):

• Gus
• Flag

Environment Light settings

Colorbleeding (also used to calculate ambient occlusion)
Environment color: black
Intensity: 1.0
ONLY emit diffuse
Bake Shadowing: RenderRadiosity (check settings two posts down)
Environment Sampling Mode: Sampled
Samples: 512
Max Variation: 0.5 (IMPORTANT! This will take out all the ugly square artefacts in ambient occlusion pass)
Max Distance: 50 - 100 (depends on how your ambient occlusion looks)
Falloff Mode: maxdist-based

Spec

Environment image: hdr_mountains1.exr (found in light-vdev_rig>light-vdev_rig.proj>sourceimages)
Intensity: 1.0
ONLY emit specular
everything else the same EXCEPT...
Max Dist: measure from Gus to environment light 
Max Variation can also be taken up to 2.0

Atmospheric Shader to Fake Fog

Here is a link to the Pixar website that has the fog.slo file and general instructions on how to use it.  For our project, just grab the fog.slo file and place it in the top level of the shot directory you're working in. 

1.) Whatever objects you want to fade into the background, you have to import the material into the Maya scene and attach it from the Hypershade.

2.) Select the shading engine of the material and add the "Atmospheric" attribute from the extra renderman attributes pulldown.

3.) Attach the fog.slo to the Atmospheric attribute.

4.) From there, you can select the Atmospheric node in the hypershade and adjust the color the object fades into and the distance from the camera that you want the fading to start.

-R.J.

Naming conventions

Kelly asked me to post about naming conventions so that it'll be easier for us to communicate and help each other out.  The system I've been using for lights and cameras is:

objectLightIsFor_specialInfo(if needed)_TYPEOFLIGHT

ex) a yellow key light for gus would be: gus_ yellow_KEY
ex  a blue fill for the background would be: bg_blue_FILL
ex) a light for specular: snowSpec_KEY
ex) for environment lights: colorbleeding_LIGHT   occlusion_LIGHT
ex) cameras for specific passes: colorbleeding_CAM, SS_CAM, occlusion_CAM

I've found that identifying the type of object at the end in all caps makes finding and organizing things in the outliner much easier and faster.  Let me know if you have any concerns.

R.J.

Subsurface Scattering and Colorbleeding settings

For SubsurfaceScattering:

• Create SSset (Select Gus skin geometry > Create > Set options > name SSset)
• Create SSlightSet (Select all lights except for environment lights)
• Under RenderMan Controls > SSRender
  • Set Camera to SSCam
  • Set Object Set to SSset
  • Set Light Set to SSlightSet

For Colorbleeding:

• Create radiositySet (Select all geometry except for glass surfaces > Create > Set options > name radiositySet)
  • NOTE: Don’t forget to add all bounce cards to the set!
• Select colorbleed environment light
  • go into Attribute Editor and click the arrow next to Bake Shadowing (rmanRenderRadiosityPass)
  • Set Camera to radiosityCamShape
  • Set Object Set to radiositySet
  • Set Shading Rate to 10.0 for now (2.0 for final renders)