Thursday, May 23, 2013

Class06 - CG Integration of characters into tracked graded footage - exterior example



open tracked camera, use imageplane to view the bg footage.
Scale the entire world, including camera, group everything, then scale.
import in a walking, fighting, running character, from Visor -> motion cap
Set up LCW with an IBL of the panoramic area, also add a directional light for sun.
Replace imageplane with Rayswitch, mip_cameramap, and sphereical_lookup

camera information -
Red Epic, shot steadicam, with 35mm Canon ef lens, 4k-HD, 3840x2160, Camera height is about 165-170cm, tracked with syntheyes.
Assume Mysterium-X with crop factor of 1.73
35mm equivalent focal length is 34.6, so they shot at 20mm
Sensor scale at shooting in 4k-HD is 20.74 x 11.66mm, which is .816 x .459 inche Maya Camera Aperture.



The bg plate sequence is a QT movie called F005_C057_1218NG_graded.mov
Import this into Nuke, and write out as a sequence of jpeg frames.
When you need to bring in a sequence of frames to the mip_cameramap, you will need a naming convention with 4 padded numbers, try jpeg for speed, you care less about quality.
filename_v01.####.jpg
The standard Mental Ray file in node mentalrayTexture will not have a sequence button so you need to replace with the Maya version called file, because that can bring in and animate a sequence.  BUT - the default connection of file.message ---> mip_cameramap.map will work fine interactively, while failing to animate in batch render.

You must disconnect and do a reconnect other from file.outcolor ---> mip_cameramap.map, this will work inside Maya and during batch render.

When you connect mip_matteshadow to some generic Lambert SG holder, be sure to connect all three color, shadow, and photons.
The ambient parameter sets a "base light level". It raises the lowest "in shadow" level. For example, if this is 0.2 0.2 0.2 the darkest shadow produced will be an 20 percent blend of background to a 80 percent blend of shadow (unless ambient occlusion is enabled).

For flipping frames that are rendered exr try the free utility called djv_view from DJV imaging

Subsurface Scatter in Maya 2013, there are a number of new shaders, most notable the shader2, skin2, and mia shaders.  Their main advantage is a per-color scattering ability which allows for the red channel to scatter more then blue and green, making for more realistic skin renders.  Also the ability to use mia_material for diffuse, reflections, highlights etc.
misss_fast_shader2_x is the sss we use in this example, hook it up to lightmap the same way the misss_fast_shader_x is connected.


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