Tutorial – FG for Animation

Recently I had to optimize rendering for a large project featuring several animated characters.
The project used final gather to create bounce lights.
Initially I thought that baking final gather at a set number of frames with the ‘Optimize for Animations’ option turned on would be sufficient.
Render Settings > mental ray > Indirect Lighting > Final Gathering Tracing > Optimize for Animations.

I couldn’t have been more wrong, the characters moved in and out of shadows and the flickering was awful.

Enter the solution: Animation Snapshots!
Animation Snapshots will create a duplicate of your model at set ranges, so if you have a sequence of a hundred frames and create an animation snapshot for frames 1-10-20 etc and bake final gather once, you will have successfully baked 11 out of 100 positions in one cycle.
Repeat the steps as necessary for 2-11-21 etc until you have all the positions of your character on you FG map.

The reason why I chose steps of ten for this example largely depends on the speed of your animation.
You will want the snapshot to not create interpenetrating models or even models that are too close because then FG would not catch bounce light and the character would still be dark for certain frames. This means if you’re animating the Flash go ahead and set your snapshot to single frames, but if your shot is a character monologue a bigger distance in key frames might be required.

Tutorial – mib_color_mix_node

In this tutorial I will introduce one of my favorite nodes in the Mental Ray tool set, the mib_color_mix node.
Often overlooked, this node will transform any material into a powerful multi-texture solution.

So let’s begin. You can find the mib_color_mix in the Mental Ray section under the Data Conversion sub-group.

You can use a mib_color_mix in any channel of any Mental Ray shader.

You will notice that the mib_color_mix is broken up into 4 sections.
From top to bottom these are, a field called Num, Mode 1-7, Weight 1-7 and Color 1-7 + Color Base.
The Color section is where you will plug in any visible maps you wish to use.
The Weight section will house your alpha maps.
Mode will determine how the layers will blend together and Num will tell the Shader how many channels to calculate.

Each layer that you add after the Color Base, will be a combination of its Color Layer, Weight and Mode settings.
So, Color 0, Weight 0 and Mode 0 will belong together and so on.

In the image below, I added a breakdown on how I used the mib_color_mix to create a multi-layered texture that
significantly reduced my memory consumption while at the same time increasing the available detail.

Click on image to view in full resolution.

Click on image to view in full resolution.

Now that we understand how the shader works, let’s take a look at how the settings affect the overall look of a texture.

Below, I added another example on how the node can be used.
The project called for a waterfall and a dynamic simulation was not a realistic option due to time constraints.
With a single texture and an mib_color_mix I was able to take a more game-engine like approach.
The same texture was overlayed four times with different UV repeat rates that were additionally animated.
Below, you can find the results of the waterfall effect.