Bench

The web app's Bench tab: attaching parts with joints, importing meshes, exporting, configs and presets.

The web app's Bench tab is a visual editor. Pick a base part, click a slot marker, attach a part with a joint, repeat. Both pickers float over the workspace — "Start a bench" over an empty tab, "Attach to …" over the scene, with the joint beside the search — and are the command palette's lists: type a few letters of a part, a preset or a command, Enter picks, Esc puts the picker away and Cmd/Ctrl+K brings it back. Drop an STL, STEP or 3MF file on either picker, or on the empty tab, to import it there. Cmd/Ctrl+K on a bench also lists what the sidebar and the scene's buttons do (Attach a part…, the exports, Start over, the selected part's Move, turn, crop and remove). A part that still has an open anchor after attaching (a Basics plate, any grid) offers it as a new marker, so assemblies stack. A bench takes up to three attached parts. Each attached part has:

• Joint and Offset (mm) — negative sinks it into its parent, positive leaves a gap.
• Shift X / Y (mm) — slide it sideways on its slot, across the mating face. The two axes are the slot's own and turn with the part's rotation, so a correction stays right whichever way the part is then turned. Made for an imported STL whose chosen face center isn't quite over the feature that should sit on the slot (a buckle whose plate runs further to one side of its prongs); catalogue parts put their own mount over the right feature already.
• Rotation (°) — turn it on its slot. Click a part in the scene (or its name in the sidebar) to select it; ↺/↻ buttons above it turn it in 90° steps, the field takes any angle. Only the part turns, never a joint's flanges. Parts whose place in the scene can be computed (catalogue parts on top slots) are clickable; imported or side-mounted ones are selected from the sidebar.
• Move and delete, from the same controls over the selected part. "Move" (or M) arms a move: the next open slot marker clicked is where the part goes — another slot on the same part or a free anchor on a different one — taking its joint, rotation, and anything stacked on it along. The arrow keys step it straight to the next open slot in that direction on the base part, no arming needed. The trash button, Delete, or Backspace removes it (and anything attached to it); Esc cancels a move or drops the selection.
• Crop — trim everything else to this part's vertical outline. A plate a few millimetres wider than the base it sits on, a bracket whose corner pokes past the rail: turn on Crop for the base (the "Crop attached parts to this outline" box under the base part in the sidebar, or the Crop button over a selected part) and whatever sticks out past its footprint, straight up or down, is cut away — in the preview and in every exported body. Only the outer outline counts: a grid of holes or a screw hole in the cropping part is not cut through the others. One part crops at a time; the part itself and a joint's flanges are never trimmed, only what overhangs.
• Fold for printing — on a part with an openConnect head (the head fused onto something, or a snap or screw as the base). A head printed standing has its layers across the neck, which a hanging load pulls apart; this exports the head's body cut just in front of the head and laid on its side, so the layers run along the load instead, as openGrid-projects' own folded snap does. Folded keeps the two halves joined by a one-layer hinge along the far side from the head: print with a 0.2 mm first layer, then fold the strip up and glue it. Split prints them apart, to glue. Only the exports change (every STL of that body, the print sheet, Layerling), and only the body the head is in: a part on a bolted joint keeps printing as it is. The scene keeps showing the bench; Folded (or Split) in the viewer's toolbar shows that body as it exports instead, with its size in the header, lit while it's on, until you turn it off or select a part. A fold needs the cut to cross the part all the way to its far side, where the hinge goes; when something sticks out further elsewhere (a GoPro buckle's prongs, say), the export says so and Split still works. One part folds at a time; the select is under the part's Crop box, and in the command palette ("Fold for printing", "Split for printing", "Show it folded for printing").
• Its own parameter editor, with the same defaults/overrides as the Library. A part attached to another may start from different values than the same part on its own (the catalogue's attached_defaults): the openConnect and MultiConnect snaps attach as their head alone (body: none), the thing you fuse onto a plate to hang it, while the version picked as a base keeps its snap body. A saved user default for the parameter still wins. The openConnect head also starts turned so its slide direction points up when it lands on a side face, the way it hangs on a wall (the catalogue's attached_up); the Rotation field turns it from there.

Resizing the base part. Click the base part in the scene, away from the parts on it (its parameters open in the sidebar), or Select base beside its name in the sidebar: its name, Crop and Deselect appear in the viewer's toolbar. Delete, Backspace, M and the arrow keys leave a selected base alone — removing it would remove everything. A base part whose size the catalogue knows (the Gridfinity parts, openGrid and Skådis boards, HSW walls, MOLLE panels, BitBeam beams and plates, Basics plates and posts, the 2020 rail…) gets small square handles, as in TinkerCAD:

• Drag one to resize. An outline shows the new size, with a label like "W 126 mm · gx 3 (+21 each side)", and the part renders once, when you let go. Width and depth grow on both sides, so the part stays centred, and height grows upward; a corner handle changes width and depth together. Counts move in their own steps (a Gridfinity unit, a grid cell, half a Skådis column); lengths snap to the Grid in the viewer's toolbar (Off, or 0.1 to 5 mm; 0.5 mm unless you change it — Settings → Editing has the same setting). Esc cancels a drag. A drag stops at sizes that still render in a few seconds in the browser and fit a large print bed (8 × 8 Gridfinity units, say); the sidebar's fields go further.
• Click a handle (or Tab to it and press Enter) to type an exact size in mm. A corner changes two sizes, so it has no box: it only drags.
• With a handle focused, the arrow keys grow (→ ↑) or shrink (← ↓) it a step at a time; Shift moves ten steps of a length. Resting the pointer on a handle shows its size.

A size that would take a slot away from a part attached to the one you resize is skipped, whether dragged, stepped or typed into a handle's box: the handle goes on to the next size that keeps every part on its slot — on an openGrid board with a part on it, 2 cells go to 4, since 3 would renumber every slot — or, with none left that way, stops at the nearest size short of it (at worst where it was), and the label says why ("3 would move attached parts"). A size typed into the sidebar's parameter fields isn't caught this way; it shows as a render error, and Undo brings the old size back.

Resizing an attached part. A selected attached part whose size the catalogue knows has the same handles, standing on its own faces however it sits: on a side face, turned to any angle, shifted, on a joint, or stacked on another part. Its controls (turn, Move, Crop, remove) move to the foot of the viewer, out of the handles' way. The face it is attached by stays on its slot: height grows away from the part it is on, and width and depth grow on both sides, so it stays centred where it sits. Parts attached to it keep their slots, as above. Its outline is the box around it square to the scene, so at a turn that isn't a quarter it is a little larger than the part; the handles are on the part itself.

Turning an attached part. Hold Alt (Option on a Mac) and drag any of an attached part's handles to turn it on its slot, as in TinkerCAD and the slicers: the pointer changes to a turning arrow while Alt is held, a dial appears around the part on the face it is attached by, and an outline shows where it will end up, with a label like "Spin 45° (+15°)". With the pointer on the dial the angle snaps to its 15° ticks (the long ones are the quarter turns, which square the part up with what it is on); pulled out past the dial it moves in whole degrees. The angle is the part's own, so a part at 37° snaps to 45°, not 52°. The part renders once, when you let go, and Undo turns it back; Esc cancels. A shifted part turns around its slot, as its Rotation field turns it. The base part has nothing to turn against: Alt-dragging its handles resizes it, as without Alt. A part without handles is turned with its turn buttons or its Rotation field.

A part whose size the catalogue doesn't know (or, for an attached part, one whose resize would also move the point it is attached by) says "Resize in the sidebar": change its size in its parameters there. Imported models have no size parameters, and no handles.

Undo. Cmd+Z (Ctrl+Z on Windows and Linux) undoes any change to the bench — attaching, moving, removing, a resize, a parameter typed (one step per field), Start over, a loaded config or preset — and Shift+Cmd+Z (Shift+Ctrl+Z or Ctrl+Y) redoes. The Undo and Redo buttons in the viewer's toolbar do the same and say what they would undo. After Start over the start picker offers Undo, and Cmd/Ctrl+Z works in its search straight away. The history keeps the last 100 steps and lasts until the page reloads, through switches to the other tabs; opening a bench link starts a new one. While you are typing in a field, Cmd/Ctrl+Z undoes the typing.

F (or the Fit button) frames the selected part, or the whole bench with nothing selected, and View ▾ looks from the Top, Front, Right or the Home view; ? lists every shortcut.

STL, STEP and 3MF import bring in any part — a Mechanism or Printables download, a supplier's CAD file, a slicer project's model — as a Bench part: click a flat face to put a slot at its centre. Hover a flat face to see its guides and snap points before placing a slot. The first slot can land at any guided position; later clicks add more on that face. Snap, inset and radius can be adjusted beside the viewer. Turn on Measure, or hold Option, to see distances from the pointer to the face edges and centre. A STEP file is converted to a mesh in the browser (OpenCASCADE compiled to WebAssembly, in millimetres whatever unit the file declares); a 3MF is unpacked and scaled by its declared unit; one that holds several bodies asks which to use. Meshes are validated and repaired on the way in (welded, winding fixed) and refused with an explanation if they have real holes. Imports live in this browser's storage only; nothing is fetched or committed. (One too large for that storage isn't kept between launches; export a config to keep it.)

Export walks the whole tree: one STL per body, or the generated .scad. Print with EasyPrint… renders every body and offers each as an STL, or all of them in one 3MF, to share or save and print from a phone with Prusa's EasyPrint (Getting started); on a phone it is the Print… button over the 3D view. Every exported file is named after the bench — <name>_<body>.stl, <name>.scad, <name>.bench.json — so a downloads folder full of them says what each one is. The Name field at the top of the sidebar sets it; a bench exported without one is asked first, with a name built from its parts proposed (gridfinity-base_gopro-female).

Configs and presets keep a bench setup itself: "Download config" writes a .bench.json (parts, parameters, joints, offsets, rotations, and any imported meshes embedded, so the file stands alone), "Import config…" loads one back, and "Presets" saves the same document under a name in your browser to reopen later — from the sidebar of a running bench, the start picker, or the command palette's "Load a saved preset…". The bench also stays put when you switch to the Library and back, and lives in the page URL, so a reload (or the link, pasted elsewhere) brings it back. The app also keeps it — imported meshes included — in this browser, so closing and reopening the app (the desktop app included) comes back to it; a config file still moves it to another device.