With my scene and 3D objects perfectly set up and and matched with our tracked footage, it was time to render it out and composite it within an other piece of software such a After Effects or NUKE.
For the time being I decided to use After Effects, where the rendered out footage would be composited using a simple layers within the software.
I came across this youtube tutorial which explains how to render out multiple layers within MAYA to be composited together later in After Effects.
Click on the title below to be taken to the video.
The tutorial covers the entire process of a basic compositing project, from exporting exporting our recorded footage to Maya, to compositing together within After Effects.
Personally I used this tutorial for its process regarding the rendering out layers with different effects (such as Occlusion or shadow) into After Effects.
I have some experience using render layers during my 15 second animation project so the process wasn’t entirely new to me.
See Blog Post:Previous experience using render layers
(Thanks Again Alec!)
To render specific objects in layers within Maya we can select them and on the bottom right of the screen in the channel box and under the render tab we can assign them to a new layer.
Naming conventions that make sense also make the whole process generally easier with regards to organisation.
So for example on the image above:
Beauty layer: Will render out as much of the scene as we want it to
Shadow Layer: Will only render out the shadows of the scene
AO PASS layer: Will only render out the occlusion information of the scene.
To only render out a certain object select everything else in the scene and in the attribute editor under render stats deselect Primary Visibility.
To apply an occlusion or shadow preset to a layer go into into the attribute editor and change its presets based of the options provided.
- Luminance Depth
- Geometry Matte
- Normal Map
If we want to test and see if our shadow layer is working, we can go into our render view and select the button that displays our shadows Alpha levels.
Before we batch render we can ensure which ones are being rendered by observing which layers have a tick or a cross to the left of render layer.
Layers with a tick will be rendered out in the batch render and layer with a cross will not be rendered.
Finally, once we have obtained our rendered out images, we can import them into after Effects as image sequences.
Finally to ensure that all of our rendered sequences match up with our recorded footage, we need to interpret our sequence.
Right click on the imported sequence within after effects, go to interpret footage and then go to main. This will open up a new window in which we can edit the frame rate of our sequence. Use this method to match the frame rate of the recorded footage with the rendered out sequences or vice versa.