The Shape Generator tool in Autodesk Inventor allows you to create lightweight models by defining specific design requirements. The process begins with an initial model that represents the approximate volume or shape needed.

After setting constraints and running the Shape Generator, a 3D mesh is produced as a reference for refining the geometry. The typical workflow involves starting with the original model, generating a 3D mesh based on the defined criteria, transitioning the mesh to the part modelling environment, and finalizing the optimized solid geometry.

How to Generate a Design Using Shape Generator:

Open the Shape Generator – Navigate to the 3D Model tab, find the Explore panel, and select Shape Generator.

Define Material & Constraints – Specify the material properties, apply constraints, and assign loads to represent real-world stresses on the part.

Set Shape Generator Preferences – Adjust settings such as mass reduction targets and refinement levels.

Preserve Critical Zones (Optional) – Select areas that must remain unchanged during the optimization process.

Apply Symmetry (Optional) – Define symmetry conditions to maintain balanced geometry.

Run the Shape Generator Study – Process the design based on the defined criteria. Modify the Model – Use the generated 3D mesh as a reference to refine and optimize your initial design

Material Assignment in Shape Generator

To assign a material, open the Material panel and select the desired material. By default, the material is set to the one assigned in the modeling environment. However, you can override this by selecting a different material from the Override Material dropdown. The Shape Generator environment allows for unique material settings that may differ from the original model.

How to Add Constraints in Shape Generator

Access Constraints Panel:

• In the Analysis tab, go to the Constraints panel.
• Alternatively, right-click on the Constraints node in the model browser and select the constraint type.

Types of Constraints:

• Fixed: Removes all degrees of freedom from a selected face, edge, or vertex.
• Pin: Used with cylindrical surfaces to restrict movement or deformation in radial, axial, or tangential directions.
• Frictionless: Applied to flat or cylindrical surfaces to prevent movement or deformation in the normal direction relative to the surface.

Applying Loads in the Shape Generator

To accurately determine a shape using Shape Generator, you can assign various loads that represent real-world forces acting on the model. The available load types include Force, Pressure, Bearing, Moment, Gravity, Remote Force, and Body Loads.

Shape Generator Settings

The Shape Generator Settings allow you to define specific design criteria for optimizing a model.

1. Mass Reduction:
2. Specify a percentage reduction in mass.
3. Set a target mass value for the final model.
4. Member Size Constraints:
5. Define the minimum member size that must be maintained in the 3D mesh criteria.
6. Ensures that wall thickness is manufacturable and meets structural requirements.
7. Mesh Resolution:
8. Adjust the resolution slider or enter a numerical value to set mesh quality.
9. Higher resolution results in a smoother, more refined mesh but requires longer processing time.

These settings help tailor the Shape Generator process to balance structural integrity, manufacturability, and performance.

Preserving Regions in Shape Generator

In most models, certain regions must remain unchanged when generating a 3D mesh suggestion. For example, areas around bolt holes or other supporting features may need to be preserved to ensure the model functions as required.

How to Preserve an Area on the Model

1. Open the Preserve Region Tool:
2. In the Goal & Criteria panel, click Preserve Region.
3. Select the Area to Preserve:
4. If a face is selected, a bounding box appears around it.
5. If a cylindrical face is selected, a bounding cylinder appears.
6. Use the Region dropdown list to switch between bounding box or cylinder if necessary.
7. Adjust the Bounding Shape:
8. To reposition the bounding shape, select Move and drag the center point using the triad.
9. To resize the bounding shape, select Size and drag the handles that radiate from it.
10. Click Advanced to enter specific values for precise positioning and dimensions.
11. Apply and Finalize:
12. Click OK to generate the preserved region.
13. Once added, preserved regions appear in the Preserved Regions node in the Model Browser.
14. Using preserved regions ensures that critical features remain intact while still optimizing the model’s design.

Once the analysis setup is complete, click Generate Shape to open the Shape Generator dialog box and then select Run to start the process. After the generation is complete, the system presents a recommended 3D mesh model that serves as a guide for refining and optimizing the design. This tool helps create lightweight and structurally efficient models while ensuring that key constraints and functional requirements are met.

Once the 3D mesh model has been generated, it can be promoted to the modeling environment to serve as a guide for refining the geometry. In the Export panel, click Promote Shape and choose whether to copy the mesh directly into the part modeling environment of the current file or export it as an STL file for separate import.

Once displayed in the modeling environment, the 3D mesh can be used to guide material removal and optimize the design. When making changes, consider using lines and arcs where possible to ensure manufacturability. Additionally, remember that the suggested modifications are recommendations based on the defined criteria—some features may still be necessary for structural integrity. Finally, using the Stress Analysis environment can further evaluate the final geometry’s performance.

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