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A Sped Up Lesson on 3D Scanning

Writer's picture: George TsakonopoulosGeorge Tsakonopoulos

Updated: Oct 18, 2024

In this blog post we are going to explore 3D Scanning technology and its advantages.

What is a 3D Scan?

A 3D scan is a three dimensional model of a real world object. It is the collection of many small points in the 3D space. These points are called point cloud. And they represent the volume of an object or scanned area.

After the initial 3D scan these data are converted in a 3D mesh model (polygon mesh).

The number of the mesh and its size, characterize the overall file size and resolution.


Point Cloud
Point Cloud



On the left picture you can see the point cloud data.

A series of many points in 3D space.

The point cloud is the first data extrapolated from the scan.









Polygon Mesh
Polygon Mesh


Next step is the conversion of the model to polygon mesh. A series of triangles the famous STL file extension format.






Where 3D scanners are used?

The list of applications 3D scanners are used for, is long. And more and more businesses utilize the benefits of this technology.

Some examples of where you could use 3D scanning are:

Feasibility Studies

By utilizing 3D scanning, CAD engineers have access to the space they design on.

This is very helpful when you have an existing assembly that you need to change some parts, retrofit or relocate them.


Feasibility study example.
Feasibility study example.

Medical Industry

3D scanning allows dentists to plan and construct implants or procedures, such as bone grafts.


dental 3D scanning

Forensics

From crash accidents to murder scenes 3D scanning provides more information compared to photos or videos.

The main benefit is that the scene can be digitized and explored a long time after the incident had taken place.


Car accident 3D scan

Archaeology and Heritage Preservation

3D scanning does not damage the object during the scan. Therefore, this is a big advantage for archaeological studies.


Archaeological  3D scanning

Art and Design

3D scanning can be used to create digital data and render a scene or video.

It is a fast way for media creators to visualize or create very realistic scenes. Additionally, you can even capture the colors of an object in order to create a realistic 3D model.


Reverse Engineering

Sometimes we do not have manufacturing drawings in order to produce an old component. By reverse engineering that component we create all the necessary engineering information to reproduce.

Additionally, reverse engineering is used in feasibility studies and engineering assemblies like the picture you see below. Thus CAD engineers have a clear picture of the design space they can work with.


Left 3D scanned data, right reversed engineered CAD model.
Left 3D scanned data, right reversed engineered CAD model.

Product Development

A big part of product development is 3D scanning, mainly for verification reasons.

It reduces the amount of prototypes needed. And sometimes we can even skip prototyping completely.


Quality Control

Verification of a product to each engineering design and specifications. You will read more details on that later on the article.


Clay Modelling

Automotive companies use clay modelling to verify in scale or real size models surface reflations, propositions or packaging.

Designers use clay as it allows them to do fast visual changes on the clay model.

By 3D scanning the final model, engineers have a digital format of the clay model and can work on the manufacturing.

Below you can check a very informative video of the development of Porsche 911.

At around 1:00 minute you will see the process of 3D scanning a clay model.


Milling from Scan Data

CNC machines can read scanned files (polygon mesh) and produce a part based in that information.


Scan Data for CFD

In the automotive industry, the design of a vehicle goes hand by hand with CFD aerodynamic simulations.

These simulations has to be done early in the design stage before the final design is signed off, as any change after that point cost a lot of money and takes time.

By 3D Scanning a clay scaled model, engineers can easily see if the designers are heading the correct direction or changes need to be made.


Fit and Finish Validation

You can use 3D scanning to validate assemblies and product finish. Engineers can use scanned files into their assemblies mixed with CAD files.



Types of 3D Scanners:


Of course, there is not only one type of 3d scanner. 3D scanners should chosen depending the application.

Below is a list with the different scanning technologies and a short description.


3D Scanner Categories:

Laser Triangulation 3D Scanner
Laser Triangulation 3D Scanner

1. Laser Triangulation 3D Scanning


In this technology the camera and the laser targets the object.

There is an angle offset between the camera and the laser which helps determining depth variations.

This technology is very famous in DIY applications as it is pretty affordable and It is an easy start to experimenting with 3D scanning.



2. Structured Light 3D Scanning


This technology ensures a fast scanning experience. This method uses trigonometric triangulation as the above example but instead of a laser it uses a pattern of light.

They are very accurate. Depending on the scanner used, the data are in high resolution as well.


Structured light 3D scan technology

Structured light handheld 3D scanner
Structured light handheld 3D scanner


A projector provides the light. The cameras that are offset compare to the projector are used to calculate the distance of each point.

This technology is a bit more sensitive at lighting conditions and reflective surfaces.









3. Photogrammetry


With this technology a series of photos are utilized from different angles.

It is a time consuming process as sometimes you need to take many close photos to each other as an overlap must be made.

There are systems that uses many cameras all around the object to reduce the processing time. All these photos are inserted in a software that does the alignment to create a point cloud.


4. Contact-based 3D Scanning


These scanners use a probe to scan the object through physical touch.

Usually the resolution of these scanners is by far superior. Maybe the most well know example of such scanner is a CMM or coordinate measuring machine, which are mainly used in industrial application and manufacturing.


Picture: courtesy of Mitutoyo

On the left is a CMM (although these can measure without a probe) let’s say a CMM is the king of scanners!

And below is 3D scanner with a probe arm configuration.

It is portable and provide increased resolution on the go.




Picture: courtesy of Faro 3D Scan










Benefits of 3D Scanning:


  • Reverse engineer an object to a CAD model that is ready for manufacturing. Or do any change you might need. The scanned data allows us to recreate (design) an object in digital form and manufacture it.


  • Saves time in design stage. CAD engineers can use scanned files in their CAD assemblies without really redesigning everything. That means they can focus only in specific components they have to design.


  • Especially for feasibility studies, where you need to check clearance and available space that can save a lot of time and bring down the design cost.


  • No need for physical object on sight. Which is not a big deal for a small component but imagine when you have a whole engine or engine bay of a car.

    For example one of the many engine bay scans we have done:



EVO 8, engine bay 3D Scan.
EVO 8, engine bay 3D Scan.

This an engine bay from an EVO 8. The customer needed custom work to be done but the vehicle was available only for a short period.

We 3D scanned the engine bay in a matter of couple hours and that’s it.

Is it an exhaust manifold, mounts for various components or an intake system? It doesn’t matter you have the 3D space available in your computer ready to be inserted into your CAD system and start the feasibility study. Check for clearance, overall available space, service provision as well as installation easy.


  • Makes prototyping process faster.

    A good scan file can help speed up prototyping phase, as it reduce the risk of errors. There many instances where we manage to have final product without prototyping.

Cad overlapping scanned data.
Cad overlapping scanned data.


One example is our charge pipe that we designed in the past.

We 3D scanned the original part. Noted all the mounting points and maintained the same clearance in specific areas.


Side by side OEM unit versus redesigned version.
Side by side OEM unit versus redesigned version.





The model you see in our example was our first try.

The result was exactly what we have been expecting. Plug and play fitment and enough clearance. In one go we had a working product. And we were able to start real work testing just in 13 days form the project started.







prototype
prototype



  • Quality control. Quality control in manufacturing is crucial as products have to meet quality standards against design specifications. For example; in an injection molding production line we can 3D scan the produced product and verify if it meets the design requirements by checking the deviation between the scanned and CAD model.


Quality control scanned versus cad model.

  • Re-manufacture parts without CAD. You can 3D scan an object and without reversing it to a CAD model you can produce the scanned file. Although, it is not as easy as it sounds, it is possible, assuming the 3D scan quality is very good. A small fiddling here and there with the 3D mesh is unavoidable but for fast changes or prototyping is a good option.


Does 3D scanning damage the scanned object?

Absolutely no. That is the main reason why we use this technology in expensive objects, artifact restoration, jewelers, humans, even crime scenes.


How to prepare an object for 3D Scanning?

The preparation depends on the scanner we are using.

There are scanners doesn't require preparation of the object at all. Although shinny-reflecting or transparent surfaces are a bit harder to scan without any preparation.

On big flat surfaces we use targets (stickers). On reflecting surfaces we use a specific powder spray to give a matte white finish on that surface. None of these will damage the scanned product. For example; a car body panel, soft or hard surface.

In the picture below, you can see the small targets were used in order to the scanner keep its position. On the other hand, scanning an object with many features will not require these targets, like an engine bay.



We hope this post has helped you to understand how this technology works. The benefits it has and the applications you could use it on.

If you have questions you can leave a comment below or send us an email at info@tpepresicion.com.




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