# Prop Model

> Use when generating a single static 3D prop — sword, barrel, chest, lantern, throne, statue, crate, key, potion, banner. One isolated object, no rigging, wired into the scene as a MeshInstance3D. Trigger on "make a sword", "generate a chest", "I need a barrel", "add a lantern model", "give me a treasure prop", "create a statue".

- **Type:** Skill
- **Install:** `agentstack add skill-summerengine-summer-engine-agent-prop-model`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [SummerEngine](https://agentstack.voostack.com/s/summerengine)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [SummerEngine](https://github.com/SummerEngine)
- **Source:** https://github.com/SummerEngine/summer-engine-agent/tree/main/skills/3d-assets/prop-model
- **Website:** https://summerengine.com/

## Install

```sh
agentstack add skill-summerengine-summer-engine-agent-prop-model
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Prop Model — Generate One Static 3D Prop and Wire It

One prop, one mesh, one MeshInstance3D. This is the bread-and-butter call of the 3D-asset family — most game-world objects are static props. The skill exists to keep two things tight: the **prompt shape** that produces a clean isolated mesh on the first try, and the **wire-in pattern** that gets the asset into the scene without leaving orphans in `res://assets/models/`.

The backing tool is `summer_generate_3d`. Default model is `hunyuan` (Hunyuan 3D v3.1 Pro — best quality). Use `trellis` when speed matters (Trellis 2 is ~2× faster, slightly lower fidelity). `meshy` is the legacy fallback — only pick it if the user asks by name.

## When to use

- "Make me a treasure chest."
- "Generate a viking axe."
- "I need a wooden barrel for the cellar."
- "Create a sci-fi crate."
- Any single, static, non-character, non-modular object the player will see in 3D space.

## When NOT to use

- Character / humanoid → `summer:3d-assets/character-model` (needs T-pose + rig pass).
- A set of matching pieces (walls, floors, doors, pillars) → `summer:3d-assets/environment-kit` (style-locked family).
- Trees, rocks, foliage → `summer:3d-assets/organic-model` (organic forgives AI artifacts; cheaper recipe).
- Cars, ships, mechs → `summer:3d-assets/vehicle-model` (hard-surface specifics).
- Walls / floors / repeating geometry → `summer:asset-pipeline/asset-strategy` Pipeline 2 (textures + CSG).
- "I just need a placeholder" → propose a primitive (`BoxMesh` / `CylinderMesh`) instead. Generation is metered.

## Steps

### 1. Search before generating

```
summer_search_assets(query="", assetType="3d_model", source="all")
```

If a fitting model exists, propose reuse:

> Found `assets/models/treasure_chest_01.glb`. Reuse this, or generate fresh?

### 2. Pick a polycount target

| Use case | Tris | Pass via |
|---|---|---|
| Hero prop (sword on hip, key item) | 3k–8k | `options: { target_polycount: 5000 }` |
| Background prop (crate, barrel, sack) | 200–800 | `options: { target_polycount: 600 }` |
| Mid-range interactive (chest, lantern) | 1k–3k | `options: { target_polycount: 2000 }` |
| Cinematic showcase (throne, statue) | 10k–30k | `options: { target_polycount: 20000 }` |

Default if you don't pass it: provider picks (~10k–30k). For most game-world props, that's overkill — pass a target.

### 3. Build the prompt

Pattern: ` +  +  + isolated-object suffix`.

| Goal | Prompt that works |
|---|---|
| Treasure chest | `A wooden treasure chest with iron bands and a heavy padlock, lid slightly ajar, gold coins spilling. Game asset, centered, stylized, white background, isolated object.` |
| Viking axe | `A two-handed viking battle axe, weathered iron head with rune etchings, leather-wrapped wooden haft. Game asset, centered, stylized, white background, isolated object.` |
| Lantern | `A medieval brass lantern with stained glass panels and a hooked handle, candle inside. Game asset, centered, stylized, white background, isolated object.` |
| Throne | `An ornate stone throne carved with serpent motifs, red velvet cushion, tall pointed back. Game asset, centered, stylized, white background, isolated object.` |
| Sci-fi crate | `A weathered sci-fi cargo crate, metal panels with yellow hazard stripes, recessed handles. Game asset, centered, stylized, white background, isolated object.` |
| Potion bottle | `A glass potion bottle with a cork stopper, glowing purple liquid inside, leather strap around the neck. Game asset, centered, stylized, white background, isolated object.` |

The `isolated object` and `white background` clauses are load-bearing — without them you get scene context (table, ground plane) baked into the mesh.

### 4. Confirm and call

> About to generate `viking_axe` via `hunyuan`, target ~5k tris. ~$0.50, ~60s. OK?

```
summer_generate_3d(
  prompt="A two-handed viking battle axe, weathered iron head with rune etchings, leather-wrapped wooden haft. Game asset, centered, stylized, white background, isolated object.",
  model="hunyuan",
  options={ target_polycount: 5000 },
  wait=true
)
```

Returns a job result with `assetId` and `fileUrl`. Treat `assetId` as the
stable handle and `fileUrl` as a fallback preview/import URL.

### 5. Import and wire

```
summer_get_asset(assetId="")
summer_import_asset_by_id(
  assetId="",
  path="res://assets/models/viking_axe.glb",
  parent="./World/Props",
  name="VikingAxe"
)
summer_save_scene
```

For interactive props (chest the player opens, lantern the player picks up),
wrap the instantiated model in a `StaticBody3D` (or `RigidBody3D` for physics
props) with a `CollisionShape3D` sibling — see `summer:scene-composition` for
the parent-shape pattern.

## Anti-patterns

- **Scene context in the prompt.** "A sword lying on a wooden table" → the table becomes geometry. Always say `isolated object`.
- **Multi-object prompts.** "A sword and a shield" → fused single mesh. Generate separately.
- **Skipping `target_polycount` for background props.** A 30k-tri barrel in the background tanks frame rate when the level has 50 of them.
- **Forgetting to import.** `fileUrl` from `summer_generate_3d` is a remote URL — you MUST `summer_import_asset_by_id` or `summer_import_from_url` before referencing it as `res://...`.
- **Generating before searching.** Reuse beats regenerate every time.
- **Picking `meshy` by default.** It's legacy. `hunyuan` is better; `trellis` is faster.

## Edge cases

- **Transparent objects (glass, ice, gem).** AI 3D gen makes these opaque. Generate the mesh, then assign a `StandardMaterial3D` with `transparency = ALPHA` and a low `albedo_color.a` in the editor.
- **Long thin props (spear, staff, banner pole).** Hunyuan sometimes thickens the shaft. Trellis handles thin geometry better — try it as the second attempt.
- **Concave interior (open chest, hollow vase).** Specify "lid open" or "hollow inside" — Hunyuan defaults to closed solids.
- **Symmetrical prop comes back asymmetric.** Add `symmetric, mirrored` to the prompt and regenerate.

## Fallback (no MCP)

The user can run the same prompt at the Summer dashboard (or directly via the Hunyuan / Trellis web UIs), download the `.glb`, drop it into `res://assets/models/`, and Godot's import dock will pick it up. Then add a MeshInstance3D manually in the Godot editor and assign the mesh.

## Handoff

After the prop is wired:

> `viking_axe.glb` imported and placed at `./World/Props/VikingAxe`. Next:
> - For physics (player can knock it over), wrap in `RigidBody3D` + `CollisionShape3D` — see `summer:scene-composition`.
> - For pickup interaction, see `summer:design-mechanic` for the pickup pattern.
> - For matching props in the same style (chest → barrel → crate as a treasure-room kit), use `summer:3d-assets/environment-kit` with this prop as the style anchor.

## See also

- `summer:asset-pipeline/asset-strategy` — the meta-router that decides between this skill and Pipeline 2 (textures).
- `summer:3d-assets/character-model` — for humanoids.
- `summer:3d-assets/environment-kit` — for style-locked sets.
- `references/mcp-tools-reference.md` — `summer_generate_3d` parameter schema.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [SummerEngine](https://github.com/SummerEngine)
- **Source:** [SummerEngine/summer-engine-agent](https://github.com/SummerEngine/summer-engine-agent)
- **License:** MIT
- **Homepage:** https://summerengine.com/

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-summerengine-summer-engine-agent-prop-model
- Seller: https://agentstack.voostack.com/s/summerengine
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.