Index Context is one of the key concepts in how Cavalry works. At first, it seemed a bit confusing. However, if you are an experienced After Effects user with background in Expressions, I’m pretty sure you used Index data in your designs. For example, by using layer Index in Expression, when building more responsive rigs and so on.

Same concept exist in Cavalry – each object generated by Duplicator has an Index value. Think of it as an ID. We can use this value to make changes or selections to specific shapes or groups of shapes. This is the basic explanation of this concept.

• Create a number of shapes
• Select only the ones you need
• Apply Behaviour or change their properties, based on selection
• Done

This is the core concept of it. It gets more complex, when you are using multiple duplicators, inside other duplicators, as shown in the tutorial above. However, you just need to use Dependency Graph to figure out the flow of Index Context data.

If you are a beginner Cavalry user, I would advise you not to worry about it at this stage. Get familiar with overall concept through Docs page and YouTube videos. Once you reach the stage, where you want more control over your designs, then look into using Index Context. Things like extracting certain shapes based on their Index Data or applying Behaviours to shapes nested inside other Duplicators or Groups and so on.

It is good to be familiar with overall concept. This way, once you feel the need for more precise and procedural control, you will know where to look for an answer.