Speed up Lighting

Introduction

If you are lighting a shot in Cycles , things can seem unbearably slow, calculating the current frame can seem interminable, getting in the way of interactively placing lights. Lets try to speed this up through 3 main techniques:

Organization

In order to stay sane, jump back and forth between interactivity and speed, it is important to keep some organizational principles in mind. This is also really important if your shot will ever be touched by another person (hint: it will!) they will thank you for doing this. So will you if you have to work in the shot for a while.

Naming

Name Lights

Keep a good naming convention for everything you add, for lights:

1. start all light names with the word light_ or lamp_ (be consistent) this will keep them together in the outliner. (Make sure you do the same for mesh lights)
2. If the light is specific to an element/renderlayer put that after the light name, for intance light_gilga_ or light_background_ etc.
3. finally, the function of the light e.g. light_gilga_fill_1 or so.

Name Layers and groups

1. Of course renderlayers have names, you should make these meaningful i.e. not 'Renderlayer.001' but 'Character' or 'Background' or 'Train' or 'Paper Rim' etc.
2. Scene Layers can be and should be named using the layernames addon (see tools)
3. If you create groups you should probably name these usefully as well!

Parenting

It can be useful to parent similar things to an empty with a good name, for instance all the lights_gilga_ you made earlier could be parented to one empty named lights_gilga. This makes them like 'folders' in the outliner, and allows shift-G select children for easy selection in the 3D view.

Groups

Alternately, you could group similar lights e.g. lights_gilga as a group. If you go to groups view in the outliner you can then see them in a folder like structure, and you can select them in the 3D View via shift-G -> Group

Scene Layers

Basically any Object you have is on a scene layer, the following conventions keep you sane:

1. Use layernames to name your scene layers in a way that makes sense (also give them types) for instance 'gilgamesh' as the name of a layer, 'Character' as the type.
2. Only place objects into layers that match the layer name (don't put the train in the gilgamesh layer, etc.)
3. Don't mix lights and Objects if possible: Place lights for one layer's items into a different (named ) layer. for instance objects in 'gilgamesh' should have lights in 'gilgamesh lights'.

Render Layers

Splitting similarly lit items into renderlayers can speed up your workflow in the following ways:

1. Interactively light only one element of your scene at a time.
2. exclude lighting and shading between renderlayers (there are no light groups in cycles yet)
3. Prepare for compositing/think about it in advance

Workflow

Ok here is a preliminary step by step workflow:

Speed settings

See settings below for some hints at speeding up rendering

Create Preliminary renderlayers

Start by making some renderlayers and placing your objects in them. They should be fairly course grained at this point (i.e. character/background/miground) or so and not very specific. Make sure you name them and your scene layers nicely.

Override materials

Create a simple material (we should make this a library item) Something like 30% grey diffuse with a little bit of glossy using fresnel mixing. override the renderlayer material with this one.

Placing Lights

Now start adding lights. Follow naming conventions above, and place them into their own scene layers (and add those to the appropriate renderlayers. You are focusing here on the placement, focus and spread of the lights , softness of the shadows etc. Intensity you can tweak later, but here you can arrive at basic lighting direction.