organic-model

Organic Model — Easy-Mode 3D Generation

Organic shapes (trees, rocks, mushrooms, coral, alien flora, crystals, vines, bones) are the most forgiving category for AI 3D generation. Lumps look natural. Asymmetry looks natural. Smoothing-group artifacts read as bark texture. The "melted" look that ruins vehicles and characters is fine on a mossy boulder.

This is the cheapest, fastest way to fill out a scene. Use it liberally — it's the recommended go-to when the user says "this scene feels empty". Each generation is ~$0.30–0.50, and the failure rate is the lowest of any 3D-asset family.

Backing tool: summer_generate_3d. Default hunyuan is great here, but trellis is faster and quality difference is mostly invisible on organic shapes — trellis is the recommended pick when generating many at once.

When to use

• "Make me a pine tree."
• "Generate five different rocks I can scatter."
• "I need glowing mushrooms for the cave."
• "Fill this forest scene with foliage."
• "Alien plants for the planet surface."
• "Coral for the underwater level."
• The user wants visual density without spending a lot of money or time.

When NOT to use

• Character (humanoid, even if "tree-person") → summer:3d-assets/character-model (rigging matters).
• Vehicle, weapon, hard-surface object → summer:3d-assets/prop-model or summer:3d-assets/vehicle-model.
• Tileable ground (grass field, sand) → summer:asset-pipeline/asset-strategy Pipeline 2 (textures, not meshes).
• Animated organic (Venus fly trap that opens, breathing pod) → generate static here, animate in-engine with bones or shape keys.
• A single hero-tree centerpiece (Yggdrasil, the One Tree) — generate via summer:3d-assets/prop-model with higher polycount and detail attention.

Polycount targets

Organic geometry tolerates aggressive polycount cuts because the silhouette is irregular — viewers can't spot poly-count drops the way they spot a low-poly cylinder.

Use case	Tris	Pass via
Hero tree (mid-distance, prominent)	4k–8k	target_polycount: 6000
Background tree (forest filler)	1k–3k	target_polycount: 2000
Distant tree (use billboard imposter)	200–500	target_polycount: 400
Large rock / boulder	800–2000	target_polycount: 1500
Small organic (mushroom, fruit, crystal)	300–1000	target_polycount: 600
Vine / branch decoration	200–500	target_polycount: 400

Generating a forest? Make 3 hero trees + 5 background trees + 3 rocks at low polycount, then scatter via MultiMeshInstance3D for hundreds of copies at near-zero rendering cost.

Steps

1. Search before generating

summer_search_assets(query="<organic type>", assetType="3d_model", source="all")

2. Build the prompt

Pattern: <species> + <state/condition> + <key features> + isolated suffix. Organic prompts are shorter than prop prompts — the model already knows what a tree looks like.

Goal	Prompt that works
Pine tree	A tall pine tree with dense green needles and a straight trunk, slight lean. Game asset, stylized low-poly game art, white background, isolated object.
Oak tree	A wide oak tree with sprawling branches and seasonal autumn leaves in orange and red. Game asset, stylized, white background, isolated object.
Boulder	A large mossy boulder, irregular weathered surface, patches of green moss on top. Game asset, stylized, white background, isolated object.
Glowing mushroom	A cluster of three bioluminescent mushrooms on a small mossy base, pale cyan glow, translucent caps. Game asset, stylized, white background, isolated object.
Alien plant	An alien spiral plant with tendril-like fronds, deep purple with glowing pink tips, growing from a bulbous base. Game asset, stylized, white background, isolated object.
Coral cluster	A branching coral cluster, bright orange and pink, sea-fan shapes, multiple branches. Game asset, stylized, white background, isolated object.
Crystal	A jagged amethyst crystal cluster growing from a stone base, deep purple with translucent facets. Game asset, stylized, white background, isolated object.
Vine	A hanging jungle vine with broad green leaves and small white flowers, ~2 meter length. Game asset, stylized, white background, isolated object.

Organic prompts that DON'T work:

Bad prompt	Failure mode
a tree	Returns a generic tree, but inconsistent species across regenerations — the scene looks chaotic. Always specify species.
a forest	Returns one fused mesh of multiple trees → impossible to scatter. Generate one tree, scatter via MultiMeshInstance3D.
realistic tree with photoreal bark	Realistic = expensive polycount, ugly when stylized assets surround it. Match scene style.
a tree on a hill	The hill becomes geometry. Always say isolated object.

3. Confirm and call

About to generate pine_tree_01 via trellis, target ~2k tris. ~$0.30, ~30s. OK?

For batch generation, batch the confirmation:

About to generate 3 trees + 3 rocks + 5 mushrooms (11 generations, ~$3.50, ~5 min). All low-poly via trellis. OK?

summer_generate_3d(
  prompt="A tall pine tree with dense green needles and a straight trunk, slight lean. Game asset, stylized low-poly game art, white background, isolated object.",
  model="trellis",
  options={ target_polycount: 2000 },
  wait=true
)
summer_get_asset(assetId="<assetId>")
summer_import_asset_by_id(assetId="<assetId>", path="res://assets/organic/pine_tree_01.glb")

4. Generate variation, not duplication

If the user wants "five rocks", don't generate one rock and copy it five times in the scene — generate five subtly different prompts:

"A medium boulder, mossy granite, rounded shape"
"A medium boulder, weathered limestone, sharp jagged edges"
"A medium boulder, dark basalt, flat-topped"
"A medium boulder, sandstone, layered horizontal striations"
"A medium boulder, mossy granite, tall narrow shape"

Then scatter all five with random rotation. Five unique meshes + rotation = looks like 50 unique rocks.

5. Wire into the scene

Use case	Wiring	Notes
Single hero tree, mid-scene	MeshInstance3D under Node3D	One per scene; nothing fancy
Forest scatter (50+ trees)	MultiMeshInstance3D with one mesh ref	Single draw call for all instances
Foliage variety (3 species)	One MultiMeshInstance3D per species	Each species is one draw call
Distant trees	Billboard imposter (Sprite3D with a tree image)	Switch from mesh to billboard at ~50m via LOD
Rocks with collision	StaticBody3D parent + CollisionShape3D (ConcaveShape from mesh)	Only for rocks the player can walk into
Rocks without collision (background)	Just MeshInstance3D	Most distant rocks don't need it

Hero tree:

summer_add_node(parent="./World/Forest", type="MeshInstance3D", name="HeroOak")
summer_set_prop(path="./World/Forest/HeroOak", property="mesh", value="res://assets/organic/oak_tree.glb")
summer_save_scene

Forest scatter (MultiMesh): create a MultiMeshInstance3D, assign a MultiMesh resource referencing the tree mesh, set instance_count to e.g. 100, and populate set_instance_transform() from a script with random positions + rotations. See summer:scene-composition for the scatter pattern.

6. LOD and billboards

For dense forests, the cheapest fix beyond MultiMesh is the billboard imposter:

1. Generate the tree mesh once at high polycount.
2. Render it from one angle to a transparent PNG (Godot's EditorScript can capture a viewport).
3. Use that PNG as a Sprite3D with billboard = enabled.
4. Swap from MeshInstance3D to Sprite3D at ~50m camera distance via Godot's VisibleOnScreenNotifier3D or a custom LOD script.

For a 200-tree forest, ~10 close trees are real meshes, 190 are billboards. Frame budget saved: ~80%.

Anti-patterns

• Generating "a forest" as one prompt. Returns a single fused mesh — useless for placement. Always one species per generation, then scatter.
• Regenerating the same species 5 times for variety. Generate 5 different species/states/colors for true variety; identical regenerations don't differ enough.
• High polycount on background organics. A 30k-tri rock used 50 times in the background tanks the frame rate. Cap distant organics at 2k.
• Ignoring MultiMeshInstance3D. 100 individual MeshInstance3D nodes = 100 draw calls. 100 instances of one MultiMesh = 1 draw call. Same visual result.
• Adding collision to every leaf and pebble. Player only needs collision on things the body can hit. Skip it for distant scenery and small ground litter.
• Using meshy (legacy). No reason to — trellis is faster and hunyuan is higher quality.

Edge cases

• Animated foliage (wind sway). Generate static here, then add wind sway via a vertex shader on the material — summer:vfx/shaders (when available). No animation rig needed.
• Underwater organics (kelp, anemones). Same flow; expect Hunyuan to add a "ground attachment" base unless you say floating, suspended in water.
• Branching meshes (vines, roots) come back too thick. Specify thin tendril, fine branches, or accept and scale Y down in the editor.
• Snow / ice / frozen variant. Add covered in snow, frosted, ice crystals to the prompt — works well on trees and rocks. For temperature variants of the same scene, generate the variant rather than retexturing.
• Crystal/glass organic. Mesh comes back opaque. Generate the geometry, then assign a StandardMaterial3D with transparency = ALPHA and emissive in the editor.
• Bones, skulls, dead trees. All work great — organic forgives them more than props would. Add weathered, sun-bleached for desert / tundra feel.

Fallback (no MCP)

1. Run prompts at the Summer dashboard or any 3D-gen web playground (Hunyuan, Trellis, Meshy).
2. Download .glb files into res://assets/organic/.
3. Build scatter scenes manually in Godot.

For totally free / offline alternatives: Quaternius (free stylized organics), AmbientCG (rocks + textures), Sketchfab free filter, Polyhaven (HDRIs + scans).

Handoff

After the organic models are scattered:

Forest scatter ready: 3 species at res://assets/organic/, 100 instances each via MultiMeshInstance3D in ./World/Forest. Next:

• Wind shader (sway in breeze): summer:vfx/shaders when available, or hand-write a vertex displacement shader.
• Ground texture (grass beneath the trees): summer:asset-pipeline/asset-strategy Pipeline 2 for tileable ground.
• Lighting / fog (forest mood): summer:3d-lighting for ambient + directional sun + volumetric fog.
• Ambient audio (forest birds, leaves): summer:audio/ambient-bed.
• Hero props (a stump, a fallen log, a shrine): summer:3d-assets/prop-model for the hand-placed standouts.

See also

• summer:3d-assets/prop-model — for hand-placed standout pieces.
• summer:3d-assets/environment-kit — pair with this skill: kit pieces give the architecture, organic gives the natural softness.
• summer:asset-pipeline/asset-strategy — meta-router; ground textures and skyboxes go to Pipeline 2 / panoramic gen.
• summer:scene-composition — MultiMeshInstance3D scatter pattern.
• references/mcp-tools-reference.md — summer_generate_3d schema.