> ## Documentation Index
> Fetch the complete documentation index at: https://docs.elisainteractive.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 📑 Understanding Élisa Custom Hierarchy

> Understand Élisa's hierarchy system, how it organizes your design sessions, and how you can leverage existing layouts within Élisa.

## What is an Elisa hierarchy

Élisa's custom hierarchy is the underlying structure used to **organize your design sessions** into manageable and **reusable chats**.

Each time you initiate a design session via **Design with Élisa**, the system generates a new **chat node**. Inside it, Élisa separates the assets you want to work with into two categories:

* **Élisa actors**: Assets placed by Élisa, or any assets manually added here to influence context and iteration.
* **Surface actors**: The base assets (usually surfaces or floors) you chose to design upon.

***

## How does Elisa lists chats

Each chat session initiated by the user is automatically stored as a **"New chat - ..."** actor within the `Élisa Chats` container.

The structure always follows this pattern:

```
* Elisa Chats *
│── New chat - ...
│   │── Elisa actors
│   │    └── <Assets placed by Elisa>
│   │── Surface actors
│        └── <Surface asset that selected to "Design with Elisa">
│── New chat - ...
    │── Elisa actors
    │    └── <...>
    │── Surface actors
         └── <...>
```

* **"New chat - ..."**: Stores the design session. Right-clicking this actor allows you to restore that session.
* **"Elisa actors"**: The context Élisa reads and builds upon.
* **"Surface actors"**: The base that was originally selected when invoking “Design with Élisa.”

<Warning>
  If one of the node is deleted, the associated design session will most likely be **corrupted and lost**.
</Warning>

To properly delete a design session, see [Clearing a surface](https://docs.elisainteractive.com/essentials/working-on-a-surface#4-clearing-a-surface) documentation page.

***

## Elisa actors vs Surface actors

Within the hierarchy, these two concepts are mapped to their respective folders under a chat node:

* **"Elisa actors"**: These represent the design-relevant actors that Élisa uses to understand and evolve the scene. They include both Élisa-placed and/or manually moved assets.
* **"Surface actors"**: These are the physical surfaces selected when starting a new design session. Élisa uses these as a spatial reference for all placements.

Keeping these roles distinct ensures Élisa understands **what to build on** versus **what to consider for context**.

***

## Using an existing "non-Elisa" layout

To iterate on an **existing layout** that hasn't been created by Élisa, you can follow this process:

1. **Select your surface assets** (usually floor meshes or anything supporting other objects). Remeber that this defines the area on where Élisa can work.
2. Right-click and choose **Design with Élisa** — this creates a new chat node in the hierarchy, along with its `Surface actors` group.
3. Then, **select all the assets currently placed on top of that surface** and **move them under the new `Élisa actors` group**.

Once moved, Élisa will treat these assets as part of the active design context. This allows you to continue **building on top of the existing layout**, with full awareness of what's already there.