Weekly Workflow: Use LunchBox to “Shell” Breps in Grasshopper

Posted on by Nicole Mater
Demonstration of the LunchBox for Grasshopper shell tool, which thickens polysurfaces parametrically.

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The latest release of LunchBox for Grasshopper includes a new Shell Brep component that brings Rhino’s Shell command into Grasshopper.

What is the Shell Command?

In Rhino, the Shell command is used to create a hollow, thickened version of a closed polysurface or surface with a specified wall thickness. It’s commonly used in architectural and product design workflows for fabricating 3D-printed models, creating lightweight prototypes, or preparing enclosures with precise material thicknesses.

Now, thanks to this new component, you can access this functionality directly within Grasshopper, enabling parametric control over shelling operations as part of your generative design logic.

Key Features

  • Native Shelling in Grasshopper: No more baking and manually shelling objects in Rhino. With the new LunchBox Shell component, it’s now part of your Grasshopper workflow.
  • Wall Thickness Control: Set wall thickness parametrically to explore different material scenarios.
  • Selective Face Removal: Specify faces to remove during the shell operation—ideal for creating open-bottom or custom-vented shells.
  • Dynamic Updates: Since this workflow is parametric, changes to your base geometry automatically propagate through to the shelled result.

Use Cases

  • Architectural Models: Generate lightweight, hollow model objects for 3D printing.
  • Product Design: Create parametric casings for electronic components or prototypes.
  • Fabrication Prep: Optimize solid models with uniform wall thickness for CNC or molding.

This component is just one of many new additions and improvements we’re adding to LunchBox — check out our other recent posts to see more . As always, we welcome your feedback and suggestions for future features. Happy modeling!

Prerequisites

How It Works

1. Input Geometry: The component accepts closed polysurfaces or open polysurfaces (Breps) as input.

  • Closed Polysurfaces: Will result in a closed polysurface shell.
  • Open Polysurfaces: Will result in an offset polysurface that is not closed.

2. Face Selection: Specify one or more face indices to remove.

3. Thickness: Set a wall thickness value, positive for inward shelling (in the direction of each face’s normal vector), negative for outward.

4. Result: The component returns a new, shelled version of the input geometry.

Thanks for following along. Have questions? Reach out to our team at apps@provingground.io.