Foreign parts and assembly mates

Definition#

A Foreign part is a fixed component from the Frame's catalogue, such as a motor, rail, carriage, pulley, battery, or fastener. It has a reference mesh, part information, optional mounting interfaces, and optional diagnostic keep-outs.

Use an attachment for printable parametric geometry. A foreign part's mesh and keep-outs never enter attachment manufacturing booleans or STL/3MF geometry. Its BOM policy determines whether it appears as purchased hardware, a reference item, or no BOM row. Pro STEP export can include purchased components as positioned faceted references.

Add a type, then place an instance#

Open Catalogue → Foreign parts. Search or browse categories, then add a type from Available to Added to frame. A new Frame can also choose its palette during creation. The catalogue manages types; it does not place instances.

Use + Add → Foreign part, choose a type in the Frame palette, then select its placement mode. Absolute shows positioning planes, Mate shows compatible mounting sites, and On-guide shows node and guide targets. Move offers the same three modes and starts in the part's current mode. Cancelling preserves the original placement.

Absolute parts expose World position (mm) and World rotation XYZ (degrees). Guided parts expose their node and link, Offset (mm) and local XYZ rotation. These fields accept numeric expressions.

Installed parts include NEMA steppers, GT2 pulleys and idlers, linear guides and carriages, dowel pins, square nuts, screws, and heat-set inserts. Choose a variant by its actual dimensions and interface contract. A matching family name alone does not establish compatibility.

Mate while adding or moving#

A mate is an assembly placement dependency. One part is the reference owner; the dependent follows its resolved interface pose. Foreign parts and Free attachments can be dependents. Physical, Virtual, and Free attachments, as well as other Foreign parts, can provide reference interfaces.

To mate a part:

1. Start adding it, or select an existing instance and choose Move, then select Mate.
2. Find a highlighted compatible owner and its precise site marker in the scene.
3. Hover the marker and inspect the translucent placement preview.
4. Click the site to accept the mate. Confirm Mated to and the owner link in the selected card.

Choose Absolute to place the part on a positioning plane. Cancelling Move preserves its previous placement and mate. Moving an already-mated part makes its current site available to itself during target discovery, so you can return it to that site or choose another valid target.

A mate aligns parts; it does not combine printed bodies, create a bolt hole, or add connector material. Use an Attachment Connection for printable grouping and authored attachment clearances for holes and receiving pockets.

Place on a guide#

Choose On-guide while adding or moving a part. Use the same green node rings, guide highlighting and hover preview as Virtual attachments, then click a node and virtual-link target. The node must belong to that guide.

The part follows the node and guide direction. The Flip direction icon is highlighted when the part faces opposite the guide; its tooltip shows the current direction. Before local rotation, +Y runs in that direction and +X follows the guide's normal. Offset moves it along +Y from the node. Local XYZ rotation aligns its purchased mesh; the mesh keeps its fixed size. Use expressions for offset or rotation when parameters should control them. The Offset (mm) row shows the expression and its evaluated distance side by side.

Use Flip direction, with the same button as attachments, to reverse the guide basis and offset direction while keeping those expressions. With zero offset, the part turns at the node. With a 10 mm offset, it moves to 10 mm on the opposite side of the node. Move to another guide retains the direction and local adjustments.

The guide name in the footer opens its selected card. Detach from guide switches to absolute placement at the current world position and orientation. Undo restores the guide relationship and its authored settings.

Several parts may share a pivot or guide. For example, the delta assembly's ball follows a crossbar while its socket follows a rod guide at the same pivot. A guided part can own mated children such as bolts. Deleting its host node or guide removes the dependent parts; Undo restores them.

On-guide consumes no mounting-site capacity and does not check physical fit or limit travel to the guide's length. Use it to express geometric relationships; use Mate when compatible physical interfaces should determine the placement.

Installation and motion#

Current Mate interfaces locate fixed installations. Symmetric coaxial mates may allow rotation for installation clocking. Use On-guide and construction nodes for sliding carriages, rotating mechanisms and ball/socket articulation. A rail and several carriages can share one guide; give each carriage a relative node when its position also drives other geometry.

Current rails and carriages retain their fixed mounting holes and screw seats. Shafts and pulley/idler bores retain fixed installation datums. Ball/socket parts retain their rod and bolt interfaces. These do not advertise motion mates.

Older documents retain their exact part definitions and behavior. A legacy sliding mate still shows Position along … (mm) and rejects travel outside its stored bounds. Its formulas and mated descendants still follow the reference owner. Legacy spherical mates remain editable too. Converting an old mechanism requires an explicit redesign of its construction nodes and guides.

Moving or deleting a mated owner affects its dependent assembly branch. Moving a rail instance alone does not move independently guided carriages: edit their shared construction geometry to move the whole mechanism. Undo restores both pose and dependency. Detach from guide preserves the current world pose while removing the guide relationship.

Occupancy and complete mounting patterns#

Targets describe physical capacity. A bolt occupying one site in a multi-hole interface does not occupy every other hole. Alternative interface descriptions can share capacity, preventing two parts from taking the same physical seat through different aliases.

Some parts require several interfaces to bind together. The preview represents the complete compatible placement, rather than a partial match through one convenient hole. Insertion direction, head style, dimensions and occupied sites can all make a target unavailable.

On-guide placement allows several carriages to share a rail construction guide. Rail mounting-bolt sites have separate physical capacity. Installing a screw does not automatically create a nut or insert; place each purchased item explicitly.

Unmate and inspect#

Select a mated part and choose Unmate. The editor removes its incoming dependency and moves it a short distance clear of the interface. Its own dependents follow. Use Move to mate it again, or Undo to restore its exact previous mate and pose.

The owner link selects the reference component. Visibility controls help inspect an assembly but do not delete parts, release occupied sites, or remove dependencies.

Keep-outs describe occupied, access, and motion space for diagnostic inspection. They do not subtract printable material. A successful mate checks the interface contract; inspect the actual hardware, access, clearances, and manufacturing fit separately.

Versions, custom parts, and transfer#

Use the Foreign Part Editor to import your own GLB and author its mounting interfaces. Publication makes a local version available to Frame palettes. Existing Frames keep their exact dependency until Use current exact release explicitly adopts a later version.

Removing a type from the palette prevents new manual placement but does not delete existing instances. A type used as the current creation default must have that default changed or cleared before removal.

Editable Frame packages carry the exact part geometry and definitions needed by the assembly. They do not create standalone editable foreign-part authoring documents. Export the foreign-part document itself when the recipient needs to revise its interfaces or registration. See editable sharing.

Related learning#

Try Guide-driven linear stage for two carriages, reactive travel, shared construction geometry and undo. Read Free attachments for printable dependents and Attachment Connections for manufacturing connectivity.