How to Model a POC Helmet in Rhino, Grasshopper & Keyshot

If you're into industrial design, you've likely worked with Rhino, Grasshopper, and Keyshot—powerful tools for 3D modeling, parametric design, and rendering. In our latest live webinar, we demonstrated a complete workflow for designing a POC helmet from scratch, integrating gyroid lattice structures, and rendering the final product in Keyshot.

Download Files: cademy.xyz/webinar7

This post breaks down each step of the process, from curve creation in Rhino to lattice modeling in Grasshopper and high-quality visualizations in Keyshot. Whether you're new to these tools or looking to refine your skills, you'll find practical insights here.

Webinar Objective

The goal was to model a POC helmet with internal gyroid lattice structures for impact absorption. We covered:

- Modeling high-quality surfaces in Rhino using NURBS topology
- Generating parametric lattice structures in Grasshopper
- Rendering animations and cross-section views in Keyshot

This workflow applies to a variety of complex, functional geometries beyond helmets, including automotive parts and product design.

Tools & Plugins You'll Need

Software:

• Rhino 3D – For precise surface and solid modeling
• Grasshopper – For generating gyroid lattices and parametric forms
• Keyshot – For realistic rendering & animation

Essential plugins:

• Global Edge Continuity – To check surface continuity in Rhino
• Weaverbird – For smoothing & subdividing meshes
• Dendro – To convert lattices into solid meshes

Step 1: Building the Helmet in Rhino

Importing the 3D Scan & Creating Primary Curves

We started with a 3D scan of a helmet and extracted its silhouette using the MeshOutline tool. Primary curves were created in the right and top viewports using Degree 4 single-span curves for smoothness.

Generating Primary Surfaces

A four-sided surface approach ensured clean topology:

• Surface from 4 Edges – For an efficient base structure
• Match Surface – To refine tangency and curvature
• Trimming Excess – To refine helmet contours

Converting to a Solid Model

Once the surfaces were aligned, we:

• Connected the front face
• Blended edges for seamless continuity
• Scaled & thickened the model for 3D printing compatibility

Step 2: Perforations & Bottom Features

Designing Vent Holes

• CurveBoolean – Defined complex vent profiles
• Fillet & Offset – Smoothed vent corners
• Project & Trim – Applied vents onto the helmet surface

Refining the Bottom Section

• Duplicated the bottom edge
• Scaled and extended the surface
• Lofted inner layers for structural integrity

A Global Edge Continuity check ensured a watertight solid ready for fabrication.

Step 3: Creating Gyroid Lattices in Grasshopper

Preparing the Mesh for Lattice Generation

• Converted the NURBS model into a mesh for easy manipulation
• Defined a Voxel Grid (e.g., 20x20x20mm) to populate the volume
• Generated a Gyroid Lattice using the Crystallon plugin

Refining the Structure

• Trimmed excess lattices to fit within the helmet
• Thickened the lattice with Mesh Thicken
• Smoothed the mesh using Catmull-Clark subdivision

The final STL export made the model ready for 3D printing.

Step 4: Rendering & Animation in Keyshot

Setting Up the Scene

• Imported the Rhino model into Keyshot
• Assigned realistic materials (e.g., glossy shell, matte gyroid)
• Adjusted HDRI lighting for depth and realism

Animating the Reveal

• Part Fade Animation – To unveil the internal lattice structure
• Rotation Animations – For an interactive design showcase
• Cutaway Material – To create dynamic cross-section views

The result? A polished, presentation-ready render highlighting both form and function.

This workflow streamlines the process of designing complex structures while maintaining functional integrity. Whether you're working on helmets or other parametric designs, mastering these tools will take your modeling skills to the next level.

Thanks for reading ❤️