Assembly
Put your parts together with joints that move, like the real thing: open a lid, slide a drawer, spin a wheel.
- AssemblyStatus bar: the Assembly tab, bottom left
- InsertAssembly toolbar
- FastenedAssembly toolbar
- RevoluteAssembly toolbar
- SliderAssembly toolbar
- CylindricalAssembly toolbar (Advanced; in Standard: More ▾)
- Pin slotAssembly toolbar (Advanced; in Standard: More ▾)
- PlanarAssembly toolbar (Advanced; in Standard: More ▾)
- BallAssembly toolbar (Advanced; in Standard: More ▾)
- Named positionAssembly toolbar
- Explode stepAssembly toolbar
- Bill of materialsAssembly toolbar
| SchoolCAD | Onshape | Fusion | SOLIDWORKS |
|---|---|---|---|
| Assembly | Assembly | Joint | Assembly |
| Insert | Insert | Copy and Paste | Insert Components |
| Fastened | Fastened mate | Rigid joint | Lock mate |
| Revolute | Revolute mate | Revolute joint | Hinge mate |
| Slider | Slider mate | Slider joint | Slider mate |
| Cylindrical | Cylindrical mate | Cylindrical joint | Concentric mate |
| Pin slot | Pin slot mate | Pin-slot joint | Slot mate |
| Planar | Planar mate | Planar joint | Coincident mate |
| Ball | Ball mate | Ball joint | Coincident mate |
| Named position | Named positions | Capture Position | – |
| Explode step | Exploded view | Animation | Exploded View |
| Bill of materials | Bill of materials | Bill of Materials | Bill of Materials |
The Assembly workspace is where you check that your design works. In the Part workspace you make the parts. In the Assembly you join them with joints that move the way the real ones do, then drag a part to try it: a lid opens on its hinge, a drawer slides out, a wheel spins on its axle.
Switch with the tabs at the bottom left of the screen: Part workspace and Assembly. Everything you do in the Assembly is saved with your design, and the parts stay exactly as they are in the Part workspace.
Instances and the fixed part#
Each part from the Part workspace is an instance in the Assembly, listed under Instances. One instance is fixed (it never moves): the first part, unless you right-click another one and choose Fix (ground).
Need more than one of a part, such as four hinges or eight screws? Click Insert and choose the part. The copy is put beside the first one; join it where it goes. Right-click an instance to hide it, rename it or delete it (the part stays in the Part workspace).
Parts in sub-assemblies (from a STEP file, or made in the Part workspace's Parts list) are listed in their folders: click a folder's name to select everything in it, or its arrow to open or close it. See Import.
Sub-assemblies that move as one#
Right-click a sub-assembly and choose Move as one (rigid group) (Onshape: Group · Fusion: Rigid Group). Its parts keep where they are to each other, so one joint moves all of it: a drawer of 70 parts needs one Slider, not 70 Fastened joints. A sub-assembly that moves as one shows (moves as one) after its name. A part in a deeper sub-assembly that moves as one goes with that one instead.
Joints#
A joint joins a place on one part to a place on another. Click:
- Fastened, Revolute or Slider on the Assembly toolbar.
- Where it joins on the part that moves: a straight edge, a round edge (the rim of a hole), a flat face, or a round face such as a pin or a hole.
- Where it joins on the other part.
- ✓ (or Enter).
| Joint | Moves | Use it for |
|---|---|---|
| Fastened | Not at all | Hinges screwed to a door, a screw in its hole, anything glued |
| Revolute | Turns about an axis | A lid on its hinge, a door, a wheel on its axle |
| Slider | Slides along a line | A drawer, a sliding door, a slide on a rail |
| Cylindrical | Turns about an axis and slides along it | A piston, a tube inside a tube |
| Pin slot | A pin slides along a slot and turns in it | A sliding latch, a linkage |
| Planar | Slides over a face and turns on it | A puck on a table, a sliding panel |
| Ball | Turns any way about a point | A ball and socket, a joystick |
The last four are on the toolbar with Advanced tools (Settings), and under More ▾ with Standard tools. For a pin slot, click the pin (its rim or round face), then the round end of the slot: the pin slides along the slot from there. For a ball, click the ball (a round face) or a hole's rim on each part.
If the two places already line up (the same hinge edge on the lid and the box, or a wheel already on its axle), the parts stay where they are. Otherwise the moving part snaps on, face to face. If it faces the wrong way, click ⇅ Flip; ⟳ 90° turns it a quarter turn.
For a hinge, click the edge the lid turns about on the lid, then the same edge on the box. For a drawer, click the drawer's side, then the side of the carcass: it slides straight out from that face.
Offsets#
Fastened, Revolute and Slider joints can be offset: Offset moves the part along the joint (a gap of 2 mm under a lid), and Offset angle turns it about the joint.
Limits#
Tick Limits and type the Minimum and Maximum, so a lid opens from 0° to 110° or a drawer slides from 0 to 300 mm and no further. Joints that move more than one way (Cylindrical, Pin slot, Planar, Ball) have a minimum and maximum for each. ⇄ Reverse direction makes positive values go the other way.
Follows#
Follows makes a joint move with another one, times a ratio (Onshape: Relations · Fusion: Motion link). A full-extension drawer slide's middle member follows the drawer's Slider × 0.5, so it comes out half as far. Dragging a part on a joint that follows moves the joint it follows.
A Drawer slide joint in the Part workspace makes the slide as its three members, with their bolt holes: the outer member goes with the cabinet, the inner one with the drawer, and the middle one is joined to the outer one and follows the drawer.
Moving the parts#
Drag a part to move it. It moves only as its joint lets it: a lid turns about its hinge, a drawer slides. A part fastened to a moving part moves with it. Press Esc while dragging to put it back.
Click a joint under Joints to show its value box at the bottom of the view: type an angle or a distance, or drag the slider. Double-click a joint (or a part it moves) to change it.
Named positions#
Move the joints where you want them, then click Named position (or + Save under Named positions) and type a name such as Lid open. Click a named position to move every joint there, with an animation. Right-click one to update it to where the joints are now.
Exploded view#
An exploded view shows how the parts go together. Click Explode step, click the parts this step moves, choose the direction (X, Y or Z, and ⇅ for the other way) and type how far. Add a step for each stage, then click ▶ Play under Exploded view, or drag its slider.
Bill of materials#
Click BOM for the bill of materials: every part, how many there are in the assembly, its material and size (length × width × thickness, as in the cut list). Download CSV saves it for a spreadsheet or your folio.
Exporting the assembly#
3D files and pictures use the parts where the Part workspace has them, unless you choose otherwise. Open the Export menu and choose Parts placed at the top: Part workspace positions, As assembled, one of your named positions (such as Lid open), or Exploded. It is used for 3D models (STEP, STL, 3MF, OBJ, GLB) and the Render, so you can render the lid open or send the whole mechanism, put together, to Onshape or Fusion.
Tips#
- Measure and Section view on the Assembly toolbar work on the parts where they are now.
- When you change a part in the Part workspace, its joints follow it: make the box taller and the lid stays on its hinge.
- A joint that would close a loop (both parts already placed by other joints) is shown with ⚠ and not used. SchoolCAD works the joints out as a chain from the fixed part.
If it does not work#
- "Click a different part: a joint joins two parts." Both clicks were on the same part. Click the other part.
- "That curved face is not round like a cylinder." Click a flat face, an edge, or a round face instead.
- A joint shows ! One of its parts was deleted, or the place it was joined at has gone after a change in the Part workspace. Double-click the joint and click the places again.
- The part will not move. It is fixed, or fastened to the fixed part. Make a Revolute or Slider joint for it.