OVERVIEW

This document approaches CAD Design from a parametric modeling underpinning to taking an approach of understanding the end result and incorporating it in the elements of design.

Herewith, we will utilize this in our first smart and connected product – the folding helmet – to ascertain that the parameters are correctly defined and nomenclatured, optimally utilized in the process of design, and form the basis for morphing the product to customizable shapes and configurations that will be the basis for our custom manufactory.

It will also provide the basis for an intelligent inference engine for our TAU Codex Transformer that will be trained to automatically design such products in the future using a combination of themed LLM (Large language model) learning, multimodal basis and the utilization of images and patterns in the future.

Each section will start with references and detail out the needs from the folding helmet perspective with image captures from SOLIDWORKS and other toolsets

TABLE OF CONTENTS

• Helmet Variants
• Parametric Modeling
• Generative Design
• Summary

HELMET VARIANTS

Here are the different types and variations of the folding helmets

PARAMETIC MODELING

Design is circular – you keep changing the parameters to iterate on the design in cycles to refine the design to specifications.

In our case it is the customization of helmets to different use cases and head shapes. It is also the variations of the considerations for shell thickness, material used, infill pattern and reinforcement, the consideration for manufacturability (in a subsequent section), the inclusion of parts and accessories, and the final assembly that need to be ascertained as part of the design process.

In a nutshell parametric modeling is 3D modeling based on relations and logical arrangements, basically geometry on steroids if you want to call it that. It is optimal for applications that ends in manufacturing.

Parameters are:

• Dimensions
• Geometric Relations

Advantages

• Reduces rework by simple redefinition of parameters.
• Enables you to create variants of models in different sizes by using parent-child relations (called families in SolidWorks).
• Easily create engineering drawings to use as communication with diverse engineering teams.
• Design evaluations, for example weight.
• Prelude to simulations to validate the design variations easily.
• Easy to extract variants for sharing with downstream constituents to serve as a contract for manufacturing and marketing capabilities, for example.

SolidWorks is a textbook example of using parametric modeling for 3D design. Either

• predefining the variables, and applying them to the sketch (hit = and global variables should appear in the input box),  or
• using smart dimensions while sketching,

enables the definition of the parameters that can be varied in the course of the design.

Here is the interface that helps define Variables in SolidWorks:

Here are tutorials on using equations in Solidworks:

Next will define the exact variables from the manifesto to enable the parametric modeling of the helmet.

Here is the EXPORT of the equations from SOLIDWORKS:
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"Head-Helmet Gap"= 16mm'Horizontal gap betwen head and helmet for adding padding etc.

"Helmet Type"= 1'1=Hercules, 2=Armadillo, 3=Athena

"Shell Thickness"= 4mm'4 mm is Default thickness, 3.2 is Medium, 2 is Thin

"Number of Slats"= 4'Total number of full slats for the design

"Movement Type"= 1'Groove/Rails/Stopper/Ledge

"Groove Depth"= 1.5mm'Depth of groove

"Rail Height"= 1.5mm'Height of rail

"Tolerance Gap"= 0.25mm'distance between slats to enable smooth movement

"Pivot Hole Radius" = 3mm + "Tolerance Gap"'Enable an M6 pin to be inserted thru the pivot point

"Stub Height"= "Groove Depth"'Height of Stub

"Groove Width"= 4mm'Width of groove indent

"Stub Width"= "Groove Width" - "Tolerance Gap"'Width of Stub

"Sliver Width"= "Number of Slats" * "Shell Thickness" + ( "Number of Slats" - 1 ) * "Tolerance Gap"'Total Width of all Slats

"Brim Width"= "Sliver Width"'Width of Brim

"Brim Height"= "Shell Thickness"'Brim height will be shell thickness

"Enclosure Lens Hole Radius"= 3mm'Nicla Vision Lens radius + offset

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Slice don’t care!

The definition of the slice, a folumated wedge based on the sliver does not care about the type of the helmet – whether it is Hercules, Armadilo or Athena. It’s bais is simply to form the basis for all the slats with approprate width to accomodate overlaps and the need to extend to the specific open angle (180 degrees in terms of Hercules and Armadillo, and 200 degrees for the Athena).

Sketches in Solidworks have 3 depiction modes:

• Blue to indicate that not all parameters are defined
• Black to indicate that all parameters are defined
• Red to indicate that it is overdesigned, in that the parameters might contradict each other.

Features are the steps you daisy chain to create a complex part that can be aggregated to an assembly.

GENERATIVE DESIGN

Our approach to customizing products will be based on utilizing paramters and encoding them into macros to quickly rinse and repeat the formalized process of designing the components of the helmet.

The nature of the design of the helmet facilitates its slicing into the individual slats and we are planning to use two approaches to accomplish this:

1. Layered Cake approach – where the individual slats are grown from a thin shell sliver by extrusion.
2. The Kirigami approach – wherein we take the entire slice and slit them into the appropriate slats. Kirigami is a variant of the Japanese Origami where objects are created by simple folds. In Kirigimi, you additionally use scissors to cut.

Both approaches are suitable for the design of the helmet and we will see which one of them gets us a better/faster way of building the macros needed to consitute the design.

Macros are scripts that let you run operations in the SOLIDWORKS software automatically. You can create a macro and program it outside of the SOLIDWORKS software, or you can record a macro that captures a sequence of actions and commands as you perform them in the SOLIDWORKS software.

You can run a macro from the Macro toolbar or the Tools menu.

https://help.solidworks.com/2021/english/SolidWorks/sldworks/c_recording_playing_macros.htm

https://www.codestack.net/solidworks-tools/

SUMMARY

NITIN UCHIL Founder, CEO & Technical Evangelist
nitin.uchil@numorpho.com