Dependencies in assemblies

The assembly browser is a hierarchical structure that shows component relationships and dependencies. Component relationships are defined by assembly relationships that control position and size and determine how adaptive components change.

How does position in the browser affect component behavior?

The browser reflects the order in which components are added to an assembly and shows relationships between parts in a subassembly. The position of a part in a subassembly determines what actions are possible:

• You can select any component in the assembly and edit it in place. Double-click the part in the browser and edit it while the other assembly components remain visible.
• You can select first-level children of the active subassembly and set them as grounded or ungrounded, display degrees of freedom , designate them as adaptive, or delete them from the subassembly.
  Note: In a subassembly, parts with underconstrained features can be made adaptive all at once. Right-click the subassembly and select Adaptive.
• To delete components, change ground status, display degrees of freedom, or designate components as adaptive, double-click to activate the first level children of the active subassembly. To edit all other components, activate the parent subassembly.

You can select any component in the browser and set its visibility , change its display color, or edit in place .

What affects component position?

The first component placed in an assembly is grounded: its origin is coincident with the origin of the assembly coordinate system , and all degrees of freedom are removed. The assembly coordinate system originates at the intersection of the default work planes in the assembly file.

Components placed after the first component are positioned with the cursor. To position components precisely, use assembly relationships to remove degrees of freedom.

You can reposition components as follows:

• Use Free Move. If the component is constrained (some or all degrees of freedom are removed), you can drag the component in any direction but it will return to its constrained position after you update the assembly. Underconstrained components will remain in the new position.
  Note: If relationships are present, an elastic band displays showing component relationships and errors. You can use Free Move to analyze and troubleshoot component relationships.
• Use Free Rotate to move the component temporarily so you can select geometry on a different plane. If the component is related to other components, it follows the same rules as the Free Move operation.
• To reposition a component precisely, delete relationships and reapply as necessary.
• Change coordinate values on the Occurrence Property tab of the Properties dialog box. Grounded components reposition immediately when you enter new coordinates; other constrained components move when you click Update.

Note: Use the DOF symbol to show remaining degrees of freedom for the selected component. (Right-click the component, select Properties, and then click the Occurrences Tab. Select the Degrees of Freedom check box and click Apply).

What affects component size?

Parts are built from dimensioned features. If you expect a feature to change size to adapt to assembly design requirements, you can designate it as adaptive. Make dimensioned features adaptive by deleting the dimensions. You can resize or reshape adaptive features within an assembly by relating them to other components or to the assembly's default work planes.

In an assembly context, you can create a part using geometry projected from faces or edges of other components. If the part containing the projected edge is deleted, the projected geometry remains intact. You cannot move, rotate, trim, or extend projected geometry.

How are adaptive components controlled?

The following rules control the behavior of adaptive components:

• In an assembly, adaptive features of adaptive parts are sized, shaped, and positioned according to the relationships applied between components.
• One occurrence of a component controls its adaptive features. For example, if you place multiple occurrences of a component in one or more assemblies, relationships applied to a single occurrence determine the size and shape of all occurrences.
• The size of an adaptive feature is controlled by its profile sketch and specified parameters. Right-click a part, select Properties to open the Feature Property dialog box, and then designate sketch size and parameters as adaptive or nonadaptive.

Note: If you prefer, select the component in the browser, right-click, and select Adaptive.

Can dependencies be derived from equations?

Assembly relationship values can be derived from equations in the assembly parameter table. Use an equation to control the angle or offset value of a relationship. For example, base the value of a constraint angle or offset on the value of another constraint angle, offset, or parameter defined in the assembly parameter table.