Is the Grand stair 3D model free for commercial use?

Yes. It is free under the 1DesignTool 3D library license: use it in personal and commercial work — games, apps, websites, renders, ads and client projects — and modify it as you like, with no credit required. What you can't do is re-sell or re-distribute the file on its own or inside a model pack.

What file format is it, and how big is it?

A single binary glTF 2.0 file (.glb), 471 KB: 6,308 triangles, 18,924 vertices and 29 materials, modelled in metres at 3.0 m × 4.4 m × 5.0 m.

Can I animate Grand stair?

It ships as a static mesh. Its 14 named parts are separate nodes, so you can move or animate each one in your engine.

Which engines and tools can open it?

Anything that reads glTF 2.0. three.js, React Three Fiber, Babylon.js, Godot 4 and Blender import the GLB directly; Unity and Unreal Engine load it through their glTF importers. The snippets above show the exact code for three.js, React Three Fiber, Godot and Blender.

How was the Grand stair 3D model made?

Claude Code (Claude Opus 5.5) generated it inside 1DesignTool's 3D template from a written brief, then the design kit's checks verified the geometry and the GLB before it was published. You can make your own the same way with 1DesignTool.

FREEcommercial use · no sign-up

Grand stair

A straight grand staircase for a decaying haunted mansion: a curtail first step, dark-wood treads and closed strings, two raked balustrades of turned balusters, candle-topped newel posts and a faded purple runner. A flat low-poly modular piece that snaps on a 1 m grid.

Original GLB471 KB Poster

Left rail: colours and the 4 knobs the agent wrote into this model — they rebuild the geometry and go into your download. Right rail: looks for the viewer. Drag to orbit, scroll to zoom.

Triangles: 6,308
Vertices: 18,924
Meshes · materials: 29 · 29
Size (W × H × D): 3.0 m × 4.4 m × 5.0 m
File: GLB · 471 KB
Animation: Static
Style: Low-poly
Collection: Haunted Mansion

Palette · named materials

trim (treads, strings, rails, newels)#3d2a1c
base (stair carcass, risers, soffit)#c9ba9c
trim (balusters)#e4ddcd
accent (carpet runner)#81688d
accent (candle wax)#f2ede2
accent (candle flame, emissive)#ec9c13
earth (candle dishes, wicks, rotted tread voids)#1b1b22
foliage (moss)#55743e

Use it

import { GLTFLoader } from "three/addons/loaders/GLTFLoader.js";

const gltf = await new GLTFLoader().loadAsync(
  "https://assets.stoicsoft.com/1designtool/3d/models/haunted-mansion-grand-stair/cfe45cb71e/model.glb"
);
scene.add(gltf.scene); // metres, +Y up, front faces +Z

How it was made

The brief given to 1DesignTool's “3D object” template:

Grand stair for the Haunted Mansion kit. Design it as one clear asset at believable real-world scale for that setting (state the size in metres in meta.notes), with its main parts modelled and named, readable at thumbnail size and from every orbit angle. It is a modular piece that snaps on a 1 m grid: give it a length in whole metres and put the origin at its snapping end, stated in meta.notes. This is one part of the Haunted Mansion kit (Low-poly style, flat-lowpoly direction): A decaying house that watches back. Use ONLY the kit palette, by name: faded purple #81688d, bone #e4ddcd, moss #55743e, candle amber #ec9c13, faded purple dark #584861, bone dark #c9ba9c, faded purple light #a497aa, bone light #f9f8f5, soot black #1b1b22, warm white #f2ede2, mid grey #7d828c, dark wood #3d2a1c. Every material's `name` must be exactly the palette colour it uses — the GLB carries these names so the kit recolours as one; an unnamed material fails delivery. Kit knob: expose a param `decayLevel` (0–1, default 0.5) for the kit's "Decay level" setting wherever it makes sense on this part, and keep that id.

Agent: Claude Code · Claude Opus 5.5 in 1DesignTool
Generation: 4.37M tokens (95% cached) · ≈ $3.28 at API prices · 5-hour plan +7%
Direction: Low-poly · family scenes
three-check PASS · glb-lint PASS

Make your own with 1DesignTool →

Named parts · 14

Grand stair
Curtail step
Stair flight
Treads
Left string
Right string
Carpet runner
Left balustrade
Right balustrade
Front left newel
Front right newel
Top left newel
Top right newel
Moss

Note: Size at the defaults: 3 m wide x 5 m long x 4.40 m tall (the upper floor/top tread is at 3.0 m; the newel candles reach 4.40 m). Grid: the footprint is exactly width x length in whole metres. The origin is the snapping end: the bottom centre of the foot of the stair (the front face of the curtail step at z = 0, on y = 0). The flight climbs toward -Z and the top tread ends flush at z = -length, y = floorHeight, ready to meet an upper-floor piece. 17 risers of about 0.176 m, going about 0.294 m. 6308 triangles in the GLB, static (no animation clip). Every material is named exactly after its kit palette colour (8 colours). The exporter writes one material copy per mesh, so the GLB carries 29 same-named materials. Geometry is non-indexed with baked flat normals so the faceted look holds in any engine. The GLB is the default build (decayLevel 0.5). decayLevel removes balusters and snaps some to stubs, rots out tread ends (dark voids), tears the runner short at the top, grows moss pads and burns the candles down. Like length, width and floorHeight, it is applied when the model is built, so it is not a live control inside the GLB. glb-lint: 0 errors; its verdict prints UNVERIFIED only because no requirements contract was supplied. Its warnings were reviewed: per-mesh material copies, intentional non-indexed geometry, height above the 1 m reference (real scale), balusters deliberately embedded in rails and strings, and parts flagged as detached that actually touch across part groups. The viewer's ground disc and lights are staging only and are not in the GLB.

About the Grand stair 3D model

Grand stair is a free low-poly 3D model from the Haunted Mansion set. It measures 3.0 m × 4.4 m × 5.0 m (W × H × D) at real-world scale and is built from 6,308 triangles across 29 meshes, with 14 named parts. Download the 471 KB GLB and drop it into three.js, React Three Fiber, Godot or Blender — free for commercial use, no attribution required.

Is the Grand stair 3D model free for commercial use?: Yes. It is free under the 1DesignTool 3D library license: use it in personal and commercial work — games, apps, websites, renders, ads and client projects — and modify it as you like, with no credit required. What you can't do is re-sell or re-distribute the file on its own or inside a model pack.
What file format is it, and how big is it?: A single binary glTF 2.0 file (.glb), 471 KB: 6,308 triangles, 18,924 vertices and 29 materials, modelled in metres at 3.0 m × 4.4 m × 5.0 m.
Can I animate Grand stair?: It ships as a static mesh. Its 14 named parts are separate nodes, so you can move or animate each one in your engine.
Which engines and tools can open it?: Anything that reads glTF 2.0. three.js, React Three Fiber, Babylon.js, Godot 4 and Blender import the GLB directly; Unity and Unreal Engine load it through their glTF importers. The snippets above show the exact code for three.js, React Three Fiber, Godot and Blender.
How was the Grand stair 3D model made?: Claude Code (Claude Opus 5.5) generated it inside 1DesignTool's 3D template from a written brief, then the design kit's checks verified the geometry and the GLB before it was published. You can make your own the same way with 1DesignTool.