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Using CAD Files to Build Augmented Reality Applications

woman using tablet to visualize cad files

A few years ago, Augmented Reality (AR) exited the Gartner hype cycle as an emerging technology. The reason was not due to lost potential, quite the opposite. It was because AR has matured as a viable technology for business investment. Nevertheless, certain challenges persist when it comes to adoption. Access to CAD files to develop interactive AR applications is one of those bottlenecks. Why is this important? Because CAD files serve as the essential building blocks for all AR initiatives.

Why are CAD files necessary in AR?

AR applications increasingly serve as a vital function of business for training, maintenance, assembly instructions, and product demonstrations. These use cases all rely on 3D models as the starting point of creating a digital twin and CAD files serve as the basis for creating those 3D models. The catch here is that the engineers and designers who create them do not necessarily consider their value as an output for Augmented Reality.

CAD files can be created in multiple types, which have different characteristics. In the 1980’s several standards were created to facilitate interoperability, but as a result these neutral formats lack features that would make them suitable for creating AR simulations. Although conversion to alternative formats is possible, they were never intended for use in the so-called “metaverse.”

Which CAD File is the Best for building AR models?

CAD files store information about dimensions and properties of parts such as volume, surface area and center of mass. These geometrical entities serve as a foundation for visualization, but in most cases the renderings are only a 2D representation of those properties. Their 3D nature is limited against a white background, and manipulable with zoom and rotation interaction using a mouse or trackpad.

As mentioned previously, CAD files come in many formats. The types of STP, OBJ, and STL are the most widely shared. If you are lucky, the CAD files you’ll have access to will be an STP or OBJ file containing sub-assemblies and component parts. However, the ultimate goal is to get files which include data attributes such as colors, materials, textures, line styles, or light sources. One example of this file type is FBX (FilmBox). Although proprietary to Autodesk, FBX files play nicely with Unity, the essential AR creation and delivery platform.

For manufacturers, attaining a CAD file with these attributes is rare. Therefore, raw CAD files will need to be upgraded to a format suitable for an Augmented Reality “experience.” This often includes file conversion and optimization to reduce the polygon count and file size. Artistic elements of photorealism are also added in.

These data attributes are important because they can be used for exploded views or interactivity between components, resulting in great visual cues when explaining assembly or maintenance instructions.

Quite often, you will get a stereolithography (STL) file. An STL file has no component parts, only surface geometry. Its existence is kept alive by its persistent use in 3D printing. While STL files are not a deal breaker, the file type is not suitable for converting to Augmented Reality in any true interactive sense. Other companion files will be needed to tell the product story.

For this same reason, photogrammetry (extracting 3D information of objects from multiple 360-degree photographs) is inherently low fidelity. The process creates a surface texture model of an object without the ability to capture its inner workings, or any interior components.

Photogrammetry as an art form has enjoyed recent technological advances, making image capture for 3D output easier and more precise than ever before. Fewer images are necessary, resulting in more photorealistic outcomes. However, they are not any more useful than STL files.

Common CAD Files and their suitability for Augmented Reality 
Drawing Exchange .dxf Native  
“Drawing” .dwg Native  
Stereolithography .stl Neutral Surface geometry 
Step .stp, .step Neutral Parts / Metadata 
Wavefront .obj Neutral Materials (.mtl) 
SolidWorks .sldprt, .sldasm Native Materials / Textures / Animations 
3D Studio (MAX) .3ds Native Materials / Textures / Animations 
Filmbox .fbx Native Materials / Textures / Animations 
GL Transmission Format .glTF Neutral Materials / Textures / Animations 

Intellectual Property Rights of 3D Assets

Asking for your customer’s CAD files can mean asking them to share their Intellectual Property. It goes without saying that businesses guard their IP fiercely, and inventions, detailed by CAD files, are foremost. In most cases though, a mutual NDA will suffice. Businesses should take comfort in the fact that most of the data in a CAD file will need to be stripped out to make it light enough for spatial computing, particularly for mobile devices. Creative studios need only keep enough elements to tell the product story, whether for maintenance, repair, service, assembly, or brand activation applications. Any more data than necessary can be a drag on rendering.

The Industry 4.0 Revolution is Challenging the Status Quo

The good news is that a fundamental change is underway led by Industry 4.0 initiatives. The devices humans use to access and interact with virtual data, including mobile devices and wearables like Microsoft’s HoloLens 2 and Apple’s Vision Pro are fueling this shift. Augmented Reality (AR) is a crucial focus of Industry 4.0, making the creation of AR-based CAD files more widespread.

In digitally transforming your business, AR and Mixed Reality applications can assist in various stages of the product lifecycle, from the initial product design (CAD) to Sales/Marketing and Service (remote assist). These interactive AR applications enhance product awareness by providing captivating demonstrations, significantly impacting knowledge retention and the customer’s comprehension of your product. Obtaining CAD files is the first step in the digitalization process.

About SphereGen

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SphereGen is a unique solutions provider that specializes in cloud-based applications, Intelligent Automation, and Extended Reality (AR/VR/MR). We offer full-stack custom application development to help customers employ innovative technology to solve business problems.

Learn more about what we do in XR: https://www.spheregen.com/extended-reality/

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