Crucible3D opens in the project lobby. Create a project with the dashed New project card (name it, press Enter), or tap any card to reopen it — each card shows a thumbnail of your scene, with buttons to rename (✎), clone (⧉), and delete (✕) it. Projects save automatically whenever you return to the lobby (tap the Crucible3D mark in the top-left, or File ▾ → All projects), and on demand via File ▾ → Save project.
The lobby's ⚙ Settings button lets you pick the viewport's color theme — Graphite (dark neutral), Espresso (dark brown with a burnt-orange grid), or Harbor (navy with a pale-blue grid). The choice applies to all projects and is remembered between visits. Individual projects can override it via File ▾ → Scene & lighting…, where an "App default" card returns the project to the global choice. Settings also has a Show gridlines toggle to hide or show the floor grid.
The same Scene & lighting… panel has Lighting switches: turn the Key light (the sun, which casts shadows) or the Fill light (soft ambient light) on or off to change the mood — dramatic single-source shadows, flat even lighting, or a dark silhouette look. These are saved per project.
Click or tap an object to select it. To select several at once, Shift-click on desktop, or use the Multi tool on touch and tap each object to add or remove it — every selected object gets its own orange highlight. With two or more selected, More Tools… → Merge combines them into a single object. Merging bakes each object's position and rotation into the shape, so the result looks identical but behaves as one mesh you can move, slice, or export together.
The Pen tool lets you draw in 3D freehand. Press and drag (or touch-drag) and a smooth tube traces your path, becoming a real object you can move, slice, deform, and export. Strokes are drawn on a plane that faces you through the scene's center — so to draw at a different depth or angle, orbit the camera first, then draw. Building a wireframe shape is a matter of drawing a few strokes, rotating between each. No object needs to be selected to use it.
A small preview window in the bottom-left corner shows your whole scene slowly rotating, auto-framed as it grows — a second angle on your model while you work. Drag the corner handle to resize it, and tap the slim arrow tab beside it to hide or show it; Crucible3D remembers both your size and open/closed choice.
Desktop: drag to orbit, scroll to zoom, right-drag (or Shift-drag) to pan. Click an object to select it; click empty space to deselect.
Touch: one finger orbits, two fingers pinch-zoom and pan. Tap an object to select.
Quick move (long-press): press and hold on any object for half a second — without picking the Move tool first — and it's "grabbed." Keep holding and drag to slide it along the ground, then release to drop. Handy for quickly nudging things into place. (Start dragging right away instead and you'll orbit the camera as usual.)
Add primitives from the left rail (desktop) or the Add button in the bottom dock (mobile) — cube, sphere, cylinder, cone, pyramid, torus, plane, and a basic head to start figures or busts from. The properties panel — right side on desktop, the Object sheet on mobile — edits the selected object's name, color, and exact position / rotation / scale, and offers Duplicate and Delete.
When nothing is selected, that same panel becomes a scene list: every object in the scene shown with its color and type. Tap any entry to select it (handy when objects overlap or hide behind each other), or use the ✕ on a row to delete it.
To wrap an image onto an object — wood grain, brick, a photo — use Import image… in the properties panel's Texture row. The image maps across the surface automatically (Crucible3D generates the needed coordinates, including for pen strokes and sliced or merged shapes). Picking a flat color again clears the texture, and textures are saved with the project and embedded in .glb exports.
Move drags the selected object along the ground; toggle the Lift chip to move it up and down instead. Scale drags on the selected object.
Rotate shows a colored axis guide around the object — three rings, red for X, green for Y, blue for Z. Grab a ring and drag to spin the object precisely around just that axis; drag anywhere else on the object to rotate it freely in any direction.
The Mesh button expands into two shape-editing tools:
Deform shows orange points on every vertex — drag one to pull the surface. Welded corners move together so the mesh stretches rather than tears.
Face lets you grab a whole face and push or pull it along its own axis — for example, drag one side of a cube to stretch it into a rectangular beam. An arrow shows the drag direction while you hold it.
Slice cuts an object in two: drag a line across it and the mesh is split by that plane, with both halves capped and nudged apart as separate objects you can move, edit, and recolor independently. A tap still selects, so you can slice several objects in a row without leaving the tool.
The More Tools… button expands into one-tap actions: Mirror creates a mirrored duplicate across the scene's center plane (handy for symmetric builds), Flip H / Flip V reflect the selected object in place, Clone duplicates it, and Hollow shells a solid object into thin walls (lighter, faster 3D prints).
With any tool active, dragging empty space still orbits the camera.
Everything lives in the File ▾ menu: save or open portable .json scene files, keep a quick save scratch slot, and export in three formats. .glb (binary glTF) carries your object colors, material finish, textures, and transparency along with the geometry — the best choice for Blender, Unity, or Unreal. .fbx (ASCII) includes colors too and opens in Autodesk tools like Maya and FBX Review (Blender needs binary FBX, so use .glb there). .obj is geometry-only, ideal for slicers and 3D printing. Deformed geometry is preserved in every format, and in undo.
Each object also has an Opacity slider in its properties panel — drag it down to make the object see-through, useful for glass, ghosts, or previewing overlapping shapes. Transparency is saved with the project and carried into .glb exports.
Crucible3D can be installed to your device like an app: in Chrome or Edge use the install icon in the address bar; on Android use "Add to Home screen"; on iPhone/iPad use Share → "Add to Home Screen." Once installed it opens in its own window and works offline.
On Chrome, Edge, or Opera (desktop), the lobby's Save to a folder… button lets you keep every project as a real .json file in a folder you choose — easy to back up or sync. Elsewhere, projects are stored in the browser, and you can always use File ▾ → Save scene file to export one by hand.
Click Animate to open the timeline. It works like claymation: pose your objects, click ＋ Capture frame to save that pose, then move things and capture the next frame. Press ▶ to play all frames in sequence, looping, at the speed set by the FPS slider.
Click any frame chip to jump to it; Update overwrites the current frame with the objects' current pose, and the ✕ on a chip deletes it. An object that doesn't exist yet in a given frame simply stays hidden until the frame where you add it — so things can appear and disappear through the animation. Frames are saved with the project, and Done leaves animation mode. Poses capture each object's position, rotation, and scale.
Turn on ◍ Onion to see translucent ghosts of the neighbouring frames while you pose — the previous frame tinted warm, the next tinted cool — so you can line up each new pose against the last, the way traditional animators use onion skin.
To share a finished animation, use File ▾ → Export: Animated .glb bakes the frames into keyframe tracks that play in Blender, three.js, and other glTF viewers, while Animated .gif renders a looping GIF at your chosen FPS — handy for posting or previews.
| G / R / S | Move / Rotate / Scale |
| P | Magic Pen (draw 3D tubes) |
| X / J | Multi-select / Merge selected |
| H | Hollow selected object |
| Shift-click | Add / remove from selection |
| V / F / K | Deform / Face / Slice (Mesh tools) |
| M | Mirror across scene center |
| D | Duplicate selected |
| Delete or Backspace | Delete selected |
| Esc | Deselect |
| Ctrl/Cmd + Z | Undo |
| Ctrl/Cmd + Shift + Z, Ctrl + Y | Redo |