Rendering workflow

I have worked out and written up a workflow that our group can follow outlining what layers to be rendered, what order to layer them in, how to layer them and which renderer to use:
_____________________________________

Rendering

The rendering will be done over seperate layers for the establishing scene. We will be using a combination of Mental Ray and a custom renderer. In the Mental Ray passes we will be rendering the colour pass, fur/hair, paint effects and fog or lighting effects. In the custom render pass pass we will render that ambient occlusion, shadows and final gathering. We will then layer these attributes together to make the final composition. The order of the layers whould be:

- (MR) Colour pass and Paint effects or Hair/fur
- (MR) Fog pass (luminosity)
- (Cst) Ambient Occlusion Pass (multiply)
- (Cst) Shadow pass
- (Cst) Final gather pass

(MR = Mental Ray / Cst = Custom Renderer)
_____________________________________

Fog test 2

This is another test I have done with a more successful result:


And the result is:


To get the above result I got the fog layer to affect the luminosity of the colour layer and then got the Occlusion layer to multiply itself with the first 2 layers. Apart from the cube in the foreground being very dark the objects in the foreground have the correct amount of density for their distance to the camera and still have their Occlusion.

Fog

We would like to get fog into the scene but may have to render it on a seperate pass. This could prove difficult because the fog has to be denser on further objects than it must be on objects in the foreground - and then theres the middleground also. This is a quick test I done to get a successful fog pass using a colour, AO and fog pass.

I then layered the fog in between the 2 passes and got this result:


This is not the result I was looking for. I have completely lost the background because the occlusion layer softened the 2 distant objects so much that the fog completely wiped them out!

Working out an efficient layer system for rendering

As I have said earlier we are planning on finishing the establishing scene of the film first and leave it to render as we work on the rest. I have been playing about with the lighting for this scene and adding elements such as global illumination and ambient occlusion. Now I have been working out how to layer these attributes together once they have been rendered. Below is an example of a colour pass which has no indirect light bounce (final gather) or self shadowing (ambient occlusion):


and this is the AO pass:



Through some tests I have found that the best way to layer these would be to use After effects or Premiere to 'multiply' the AO ontop of the colour pass. The multiply action will erase all the white from the AO pass and keep the black, which will be the shadows.

Lighting

These are a few test renders for the lighting I am working on for the opening scene with the truck (which was modeled by Luke and Rey. This is the untextured scene at the moment, I just blocked it out with colour so I know what goes where. Im not very happy with the colour of the sky at the moment but I assume that I will be replacing it with a sky texture later.

Grass

I have been working on making the grass for the opening shot using a technique Rey showed me with hair follicles. So far this is the result:



Hair follicles are appearing to be very unpredictable for making the grass seem like its swaying, ill have to spend alot more time to make it look convincing.