Autodesk Inventor: Skeleton Modeling Basics
by Neil Munro Welcome back to our tutorials on working with Autodesk Inventor? software. In this installment, we examine a lesser-known assembly-modeling technique often referred to as skeleton or master model modeling.
No strict set of rules applies to skeleton modeling, and you can use many variations of the basic technique to suit your specific modeling requirements. The basic process for creating a skeleton-based assembly is as follows:
1. Create a single part model consisting of base sketches for all, or a subset, of the assembly components. Position the sketches to reflect the position of the component in the assembly.
2. Include construction surfaces, work features, and even solid geometry to be used as feature terminations or reference geometry during assembly component modeling. The sketches and other geometry form a skeleton of the final assembly.
3. Edit parameter names in the skeleton part, and export any key parameters that may be required in the individual assembly components. 4. Start a new assembly. Create each part (or subassembly) in-place and select the Assembly XY Plane as the location for the initial sketch for new parts. The common starting plane for each part is important if you are to retain the relationships between the new parts because all new parts use the skeleton part as their foundation. 5. Exit the initial sketch for the new part. Then use the Derived Component tool to import the skeleton part. You can filter out sketches, work features, and surfaces that are not required to create the base feature of the component.
6. Create the base feature of the component from the derived geometry. Add additional features as required.
7. Return to the top-level assembly and ground the component. Optionally you can place assembly constraints between the origin geometry of the component and the top-level assembly to lock the position of each component in the assembly.
8. Repeat the above steps for all components defined in the skeleton model. To make changes to the assembly, edit the skeleton part and then update the assembly to reflect the changes in all components affected by the skeleton part.
Skeleton Part Review The part file included with this tutorial is the completed skeleton part. We'll examine this part prior to creating the assembly. Download (zip - 127 Kb) You can download the files used in this tutorial from here.
Tip: Keep the skeleton model open as you build the assembly. In a complicated skeleton model, you may well want to hide sketches and other geometry to reduce the filtering required when deriving the skeleton model into the assembly components.
1. Open SkeletonBase.ipt The part should match the one shown in Figure 1.
Figure 1: Skeleton part.
The part contains sketches, work features, and construction surfaces that define the basic geometry of a support frame for a spherical container. Skeleton models are particularly suitable for static models, such as frames and other fabricated assemblies. The jumble of geometry may look a bit confusing, so let's look at the individual sketches and other geometry in the part.
2. In the browser, drag the End of Part Marker and drop it just below the STRAP SURFACE node.
3. Click the Look At tool on the Standard toolbar, and then click CIRC STRAP SKETCH in the browser. Your view should match the one shown in Figure 2.