Skeletal Modeling (a type of Top-down Design) is a technique that facilitates centralized design criteria and creates components that reference those criteria. Many variations of this technique exist and can be used in both Express mode and Full mode. The basic workflows are as follows.
Note: Use the common origin workflow to derive shape and position to your new components. Use the position independent workflow to derive shape only. With position independent components, changes to the position of sketch geometry in your layout do not require component revisions. Also use the position independent workflow with sketch blocks to create kinematic layouts; Make Components translates sketch constraints to equivalent assembly constraints to achieve the kinematic behavior.
Common origin
- Create a single part model, called the skeleton, consisting of base sketches. These sketches reflect the layout of the assembly components. Position the sketches to reflect the position of the components in the assembly.
- Include construction surfaces, work features, and even solid geometry to be used as feature terminations or reference geometry during assembly component modeling.
- Establish all critical parameters in the skeleton part. Be sure to name the parameters appropriately and mark them for Export.
- Use Make Part, from within your layout, to create a component in your target assembly. Select the sketches, work geometry, features, and bodies to derive into the component. The new component is grounded at the assembly origin.
- Continue to model the primary features of the component from the derived geometry. Add additional features as required.
- Repeat these steps for all components defined in the skeleton model. To change the assembly, edit the skeleton part, and then update the assembly to reflect the changes in all components affected by the skeleton part.
To avoid crowding the highest-level skeleton with too many sketches and features, derive additional skeleton parts from the master skeleton to represent or add details for sub-assemblies.
Position independent
- Create a single part model which consists of your 2D layout sketch. The sketch reflects the primary layout of the components in your assembly.
- Use 2D sketch geometry and sketch blocks to represent your components.
- Establish all critical parameters and mark them for Export.
- Use Make Components, from within your layout, to create new components in your target assembly. Select the sketch blocks to derive into components. Your layout part is placed in the target assembly. You new components are constrained to the layout part using Layout constraints. Constraints between sketch blocks in the sketch are translated to assembly constraints.
- Continue to model the primary features of the components.
- Repeat these steps for all components defined in the layout. Your layout controls the shape of your components, and their position within the assembly. If you change the layout, your components are updated accordingly.
Note: Component shape is derived from layout sketch blocks, while component position is controlled by the Layout constraint. The Layout constraint positions your component relative to the layout part. As the layout part updates to reflect positional changes in the layout, component positions in your assembly are also updated. However, since the components have not changed, revisions to the component design are not required. Only changes to the assembly documents are necessary.