Week 2
The big focus of week 2 has been the environment light and the cast shadow on the cg objects. As I mentioned in last weeks blog post, the image set I chose did not contain a reference photo of a mirror ball to match the HDRI direction. Despite missing the reference I was able to match the highlight from the HDRI with the highlight of my spot light.
Next up was the shadows. In Nuke I created a matte for where the shadows where on the original clean plate. Initially I attempted to create this with a luminance key, but I found manually drawing them on with a roto shape was much faster and had less issues in the softer parts of the shadow.
From there I took the matte into my Maya scene and projected the image from the camera to the ground plane in a new render layer. I then created a new second camera place in the same position and direction of the spot light so I could render the matte image from the perspective of the spotlight.
I returned to Nuke to extend the matte image from the spotlights perspective, so that as I went back into Maya it would go beyond what the camera sees. This time I projected the image from the spotlight camera onto the objects of the scene, while hiding the ground plane in the render. By doing all of these steps I now have a render pass that includes both the ball and the football swimming through the matte similar to the affect of a shadow, that will allow me the freedom to control it in compositing.
To prepare for rendering I created AOV light groups for both the spot light and the sky. I separated out both the direct and indirect for the diffuse and glossy passes for each light so that I could manipulate them independently in Nuke. A problem that I did notice from this was that the original light from the HDRI is present in the specular direct pass for the sky dome, meaning I will have to paint it out of the HDRI at some point.
To finish of the week I brought all of my passes into Nuke and used my new projected shadow matte to cut a hole in the sun’s direct light pass, essentially making the light not visible in that are (aka in shadow).
example of the problem
Shadow matte projected from the spot light position.
New Render Passes
Updated Nuke Comp
