> For the complete documentation index, see [llms.txt](https://studio-docs.sandbox.game/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://studio-docs.sandbox.game/the-editor/how-to-use-mesh-models-and-modelmesh.md).

# How to use mesh models and ModelMesh nodes

A `.glb` in the Assets panel is a **mesh model**. Dragging it into the scene does not copy the file. It creates a **Model Mesh Node** that points at that file.

A **Mesh Node** is different: a primitive box, sphere, or capsule with no `.glb`. The Ground in a new project is a Mesh Node.

When the agent places a character, a prop, or a wall from a model file, it is creating a Model Mesh Node. Select the node and read `modelUrl` in the Inspector to see which file it uses.

## Mesh model vs Model Mesh Node vs Mesh Node

| Thing           | What it is                                                                          | How you get one                                                          |
| --------------- | ----------------------------------------------------------------------------------- | ------------------------------------------------------------------------ |
| Mesh model      | A `.glb` file under `assets/models/`                                                | Import or generate the file. It stays in the Assets panel.               |
| Model Mesh Node | A scene node (`ENGINE.ModelMeshNode`) that displays a `.glb`                        | Drag the file into the scene.                                            |
| Mesh Node       | A scene node (`ENGINE.MeshNode`) with built-in geometry (box, capsule, and similar) | Primitives on the left toolbar, or the Ground that ships in a new scene. |

Two Model Mesh Nodes can share one `.glb`. Change `modelUrl` on a node to point it at a different file. The original file is unchanged.

{% hint style="info" %}
*NOTE: Older prefab JSON may say `ENGINE.ModelMeshComponent`. In the editor and Inspector the class is **Model Mesh Node**. Same object.*
{% endhint %}

{% stepper %}
{% step %}

## Drag the model into the scene

In the Assets panel, find a `.glb`. Drag it into the viewport.

A new node appears in the Outliner. It is named from the file: `chickdefault.glb` becomes `Chickdefault`. Its class is `ENGINE.ModelMeshNode`.
{% endstep %}

{% step %}

## Read the model path

Select the node. In the Inspector, `modelUrl` is a fully qualified path, for example `@project/assets/models/default.glb`.

That path is the link between the node and the file. Moving or renaming the `.glb` without updating `modelUrl` leaves the node empty.
{% endstep %}

{% step %}

## Move, rotate, or scale the node

Placement lives on the node, not on the `.glb`. Use the transform tools, or type values in the Inspector. See [How to Place Move Rotate and Scale an Asset](/the-editor/how-to-place-move-rotate-and-scale-an-asset.md).
{% endstep %}

{% step %}

## Leave Model Material empty unless you are replacing the look

Kit and generated `.glb` files already have materials packed in the file. Leave **Model Material** empty to keep that look.

Override only when this node needs a different surface: create a material (`New Asset` → `Material`) and set **Model Material** to that `.material.json` (convention: `@project/assets/materials/M_Floor.material.json`).

The `.glb` does not change. Other nodes with an empty **Model Material** keep the file’s own look. Full steps: [How to set up materials](/the-editor/how-to-set-up-materials.md).
{% endstep %}
{% endstepper %}

## What a dragged model gets

These are the Inspector defaults after a drag. Change them when the prop needs something else.

* Physics on: motion `static`, profile `BlockAll`, collision mesh `convexHull`
* `castShadow` off
* `receiveShadow` off

Turn **Cast Shadow** and **Receive Shadow** on when the model should take part in lighting. See [How to use shadow](/the-editor/how-to-use-shadow.md). Physics and AI pathing: [How to set collision and navmesh on mesh models](/the-editor/how-to-set-collision-and-navmesh-on-mesh-models.md).

{% hint style="info" %}
*TIP: A character usually has a hidden Mesh Node capsule for collision and a Model Mesh Node child for the visible `.glb`. Replacing the look means changing `modelUrl` on the visual node, not replacing the capsule.*
{% endhint %}

## When to use which

* **Imported art** (characters, kits, marketplace GLBs) → Model Mesh Node.
* **A row of the same kit piece** → many nodes, one `.glb`. See [How to kitbash a level from mesh models](/the-editor/how-to-kitbash-a-level-from-mesh-models.md).
* **Blockout, floors, hidden colliders** → Mesh Node.
* **The same mesh many times** (foliage, repeated props) → instanced mesh. See [How to instance repeated meshes](/the-editor/how-to-instance-repeated-meshes.md).
* **The same setup more than twice** (jump pad, pickup, enemy) → save the node as a prefab. See [How to Set Up a Prefab](/the-editor/how-to-set-up-a-prefab.md).

## Common mistakes

| What went wrong                                  | What to do                                                                                        |
| ------------------------------------------------ | ------------------------------------------------------------------------------------------------- |
| Asked the agent for a “mesh” and got a blank box | That is a Mesh Node. Ask for a Model Mesh Node and pass the `@project/assets/models/...glb` path. |
| Edited the `.glb` in the scene                   | You cannot. Edit placement and materials on the node. Replace the file, or change `modelUrl`.     |
| Assigned a material and every copy changed       | They share one `.material.json`. Duplicate the material if one copy needs a different look.       |
| Expected a Shader object                         | There is no Shader asset. Create a **material** and assign it on **Model Material**.              |

## What You've Done

You can tell a `.glb` from the Model Mesh Node that displays it, and a Mesh Node that has no model file. Next: [How to set up materials](/the-editor/how-to-set-up-materials.md), [kitbash a level](/the-editor/how-to-kitbash-a-level-from-mesh-models.md), or wrap a finished setup in a [prefab](/the-editor/how-to-set-up-a-prefab.md).


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