3D Models in Technical Documentation – How to Get Started

The text and the model can be directly linked to each other. If a component is mentioned in the text, the term can be presented as a link that the user can click to view the corresponding component graphically highlighted in the 3D model, e.g., by color or by detaching it from the main product and displaying it in the foreground.

In turn, the 3D model becomes a navigation tool: if the user clicks on an element of the model, the corresponding page opens automatically in the manual. This means that users do not first have to know what a component is called to access the information they need, but can simply click on the part instead.

Animating 3D models gives you a very clear way of showing how to assemble a device, for example, or which steps should be carried out on which component.

It’s important to note that 3D models do present some challenges too. But what are they and how can they be managed? The two most serious issues are the security problems associated with 3D models.

As 3D models contain metadata, they can be exploited as starting points for industrial espionage. For example, the data may contain the names of the people who designed the device, who can then be targeted through social hacking attacks. Or the metadata could record the tolerances of the components, a coveted piece of information for product pirates. So before using 3D models, you need to make sure that all the metadata that are unnecessary for the documentation are deleted.

However, the 3D model itself can also be a starting point for industrial espionage and reverse engineering, as it contains the complete outline of the product. The dimensions of the product must be made unrecognizable to prevent a competitor from reading out the relevant data. Modern M-CAT systems are able to randomly rewrite geometries within certain limits in order to protect against just such a danger. The advantage of this is that the data are not merely hidden, but completely destroyed. These 3D models are thereby rendered completely unsuitable for a reverse engineering attempt; it would frankly be easier to get hold of one of the machines and physically examine it instead.

There may also be some other minor problems that arise, such as not all parts of the end device being modeled in the R&D department that provides the 3D model data. Purchased standard parts such as hydraulic hoses or plug connections are often missing. Your technical writing department should check this before deciding on a 3D model and determine whether you can do without these parts or need to model them retrospectively.

3D data are already available in many manufacturing companies. In most cases, 3D models have already been created during the product development phase using M-CAT systems such as Autodesk Inventor or Solid Edge. Once created, these models are usually entered into a product lifecycle management (PLM) system where the different versions can be managed alongside additional, supplementary data.  

In addition, an engineering bill of materials (EBoM) is usually compiled in the ERP system during product development. This records all the components and materials used in the manufacture of the device and is essentially the “map” and inventory for the entire product. 

With the models and the EBoM together, we actually have everything we need as technical writers. However, the 3D models are far too large to use in technical writing departments, because a single model often consists of several hundred GB of data. These models are therefore not (yet) suitable for technical writing purposes and for publication on a website, for example. 

Sometimes 3D models are already available in more data-saving “lightweight” formats. This may be the case if the system used to manage the spare parts catalog (EPC) also works with 3D models, for example. In this case, the technical writers are already using a complete database.  

If there are no such lightweight formats in the company so far, the 3D models can also be transformed in the technical writing department itself using one of the authoring tools available on the market for the secondary use of 3D models. The advantage of this software is that the license costs are significantly lower than for complete systems, plus the training time for technical writers is reduced due to the smaller range of functions. The most important thing when choosing the right one for you is that the software is capable of randomizing dimensions and removing metadata. 

Now the technical writer has to decide in which way users are to be presented with the instructions containing the 3D models: as a 3D PDF or as an HTML application. HTML has become the standard format for publishing instructions containing 3D models. The viewer for the models is usually supplied by the 3D authoring tools and can be conveniently integrated into the website as JavaScript. There is therefore no need for the customer to do or install anything to view the models – a requirement that would otherwise make the use of 3D documents doomed to fail. However, this solution is only possible on web servers; file-based, static documentation (e.g., supplied on a DVD) must therefore usually continue to rely on 3D PDF.  

When 3D models are hosted on websites, the WebGL standard – which enables a high-performance experience for the user even on mid-range PCs – is used. WebGL is a standard that all common authoring tools offer as an export format.  

After they have been exported from the authoring tool, the 3D models are imported as resources into the component content management system of the technical writing department, where they can be referenced from the content, similar to images and videos.  

In SCHEMA ST4, the system automatically detects that 3D content has been included at the referencing location. SCHEMA ST4 then takes this into account when producing the target formats and automatically generates the customized JavaScript code that ensures the model is displayed. This functionality is a standard feature of SCHEMA ST4 and can be used out of the box. Experienced users can also use Online Media Designer (OMD) to customize the functionality themselves and tailor it even more precisely to their needs. 

All in all, working with 3D models is much easier than you might think at first. Often there are already usable data available in the company. And even if these are not yet available, a lightweight model can be created with a little training. After that, handling in the content management system is a breeze. The way is therefore clear for all technical writers to unleash the power of 3D in technical documentation.