There are times when you only have less than desirable 3D scan data to work with. Unfortunately, that is the only information available for use to reverse engineer a part from scan to CAD.

You might be in this situation because of the following reasons:

1. You used a low-cost 3D scanner that is not capable of capturing high-quality scan data.
2. You are scanning a shiny, transparent, or dark surface and it wasn’t coated with a 3D scanning spray prior to 3D scanning.
3. You were scanning in direct sunlight and your 3D scanner isn’t capable of performing at its optimal performance.
4. Time restrictions didn’t permit you to go back to rescan the part in order to get the best results.
5. Someone else gave you the scan data for reverse engineering it into a CAD model.

However, don’t worry if you weren’t able to get high-quality scan data. Sometimes where or how you obtain the source data is not within your control. In this article, we’ll show you how to reverse engineer with less than desirable 3D scan data.

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Video Demonstration

Here’s a video demonstration of the process that shows different ways to go about it. It also includes the thought process one would go about reverse engineering an object from less than desirable 3D scan data.

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Takeaway

As you can see in the video, we’ve taken two approaches to reverse engineering from rough 3D scan data.

• Method 1: Reverse engineering as closely to the 3D scan data as possible
• Method 2: Reverse engineering to the design intent (as opposed to just copying the scan data exactly as in Method 1)

The video brings out an important topic, which is the design intent.

Reverse engineering in some ways is like detective work. The scanned data contains clues as to how the original part was designed and functioned. It’s up to you to deconstruct someone else’s work to create your new CAD model.

In the real world, it’s difficult to manufacture products perfectly. Sometimes a physical part might be manufactured slightly off-specs. It might also change from its original design due to normal wear and tear or damage. It’s up to you to do a bit of investigation to understand what the original designer had in mind when designing the original part and then go about making the appropriate modifications as you see fit.

Do you want to:

• (A) Build a new CAD model exactly like the physical object? (as-scanned part)
• (B) Create a new CAD model based on what the original designer had intended? (design intent – what the part should be rather than what we’re seeing from the rough scan data)
• (C) Or, use the scan data to make modifications to the original part? (improved design)

This is why reverse engineering involves a deeper understanding of how the part was originally designed and what you want to do with it (the outcome). It’s about taking a step back and seeing the function versus merely tracing the scan data without putting much thought into it. A lot of times this means that you need to take a methodical approach by analyzing and planning how you want the final model to be—even before you start the reverse engineering process.

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Examples of Design Intent

Example 1

From Video: How To Reverse Engineer Less Than Desirable 3D Scan Data

Software: QUICKSURFACE

When we were reverse engineering close to the scan data (Method 1), we varied our thickness when sketching the 2D profile which was based exactly on what the scan data showed.

However, in Method 2, we figured that bent sheet metal would be the material that was used to manufacture this part. Consequently, it would make logical sense to make sure our sketch has a consistent thickness all across the part. We also determine the part is symmetrical so the center was found to mirror one side to another.

Method A: Sketching Exactly To Scan

Method B: Figuring Out Design Intent

Final CAD Model

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Example 2

From Video: How To Reverse Engineer From Scan to CAD Using Color Texture Information

When creating a CAD model of an existing skateboard, we inferred that the part should be symmetrical. As a result, we made the design choice to mirror one side of the design to create the other.

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Asking the Right Questions

To make the Scan to CAD process easier, here are some important questions you should ask to make sure the final CAD model you create would truly satisfy your goals:

• Why do you need to create a CAD model from this physical part?
  (Purpose – Is it to replicate, design the CAD model true to the original, modify, or improve the part?)
• What does this part do?
  (Functionality – What or how will it be used?)
• Where does the part go?
  (Mating Surfaces – What are the critical dimensions/interactions?)
• How will this part be made?
  (Manufacturing Process -What type of material will be used to manufacture the part?)

Depending on what you want to accomplish, whether you need to replicate the part exactly because you have to manufacture an identical automotive component as a replacement part for a vehicle or you are looking to create a new and improved product, scan data gives you existing knowledge to make inferences. It’s more accurate than designing from scratch or using traditional hand tools, such as calipers, especially for designing organic and complex parts. 3D reverse engineering makes your job much easier.

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  3 Affordable Scan to CAD Tools Not Just For CAD Specialist [With Video Demos]

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  A Detailed Guide to Reverse Engineering from Scan to CAD In SOLIDWORKS [With Videos]

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  Happy Hour Workshop – Reverse Engineering from Scan Data to CAD

In our previous blog post, How to Scan Dark, Shiny, or Clear Surfaces with a 3D Scanner [With Video Demo], we covered why and how some surfaces are more challenging to scan than others using an optical 3D scanner. These include dark, shiny, transparent surfaces, as well as holes and pitted areas.

To help you get the best results, we recommended spraying the part with a developer spray to cover challenging surfaces with a white coating. It’s a temporary coating that easily comes off. You can wipe off the spray with a cloth after the part is scanned.

Since the article was published, our team has been getting questions on YouTube as to what would be the best solution if a surface can’t be cleaned.

Challenge

Questions from Video:
How to Scan Dark, Shiny, or Transparent Surfaces with a 3D Scanner

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Solution

Luckily, now there’s a solution that can help you out if you run into any of these situations. The AESUB Blue vanishing 3D scanning spray was developed and approved by 3D scanning experts for scanning challenging surfaces (reflective, clear, dark, and difficult to reach pitted areas).

What’s special about this spray is that It leaves no mess and disappears without a trace after your 3D scanning job is complete.

It’s especially great for projects where you are:

• 3D Scanning Fragile Parts: Working with scan parts that cannot be sprayed or cleaned. AESUB Blue uses a special, evaporating formula that requires no cleaning, won’t stain your surfaces, or affect your product.
• Doing Quick Jobs: Great for doing quick jobs where you only need to scan the part for a short period of time as the spray will vanish with time (within a few hours). No need for cleanup!

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How It Works: A Step-By Step Guide

Here is a step-by-step tutorial of how to 3D scan a reflective part using AESUB Blue 3D scanning spray.

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How Long Will It Take for the Spray to Vanish?

It would depend on the following factors:

• How much you sprayed
• How big your part is
• Airflow (wind speed across a part – under AC vent vanishes faster)
• Environmental and temperature conditions

Tip: You should use the following videos as a guideline for how long it would take for your part in consideration. If you want the coating to last longer on a part, you should reduce the airflow in the room or put it in a closet to slow down the pace of sublimation.

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AESUB Blue Vanishing Spray Analysis

1. Analysis of Spraying the Part Versus Untreated Surface

   To better understand the technical aspect of the layer’s thickness and homogeneity of the AESUB coating, we did our own analysis. Check out the video:

   Takeaway: Due to the nature that optical 3D scanners use projected light source in the 3D scanning process, the results will be affected by challenging surfaces to a certain degree when left untreated. While AESUB Blue vanishing spray adds ~8-15 microns of thickness to the part’s surface, it provides a consistent layer that aids the 3D scanner in capturing the true nature of the part, without the distortion caused by the challenging surface.

2. Analysis of Spraying the Part with AESUB Blue Versus Comparable Product

   The manufacturer of AESUB Blue conducted its own lab testing by comparing spraying a surface with AESUB Blue (left) and a CCD vanishing spray previously used in measurement technology (right). The measurement shows a 3D scan of a glass sphere with a diameter of approximately 130 mm.

   

   Takeaway: As you can see from the image, AESUB Blue provides a consistent scanning surface compared to a similar product. The sprays provide a thin and homogenous coating—leaving a clean, smooth, and even application with no clumps left behind.

   Another amazing quality of this spray compared to other products out in the market is that it’s less toxic.

3. Residue Analysis

   An examination of AESUB Blue for potential residues.

   

   

   Takeaway: AESUB Blue provides neither recognizable nor measurable residues and therefore be regarded as residue-fee.

   View the full residue analysis report

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Recognized for Innovation

There’s no other 3D scanning spray out there quite like it. The AESUB Blue vanishing 3D scanning spray is so revolutionary that it recently landed on Develop3D’s D3D 30 List which features 30 new technologies that give 2020 product development work a major boost.

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What If I Need a Permanent Spray?

There are still times when your 3D scanning project can last for more than a few hours to even a couple of days. AESUB has a permanent alternative called AESUB White that provides similar benefits to AESUB Blue except it’s a permanent spray.

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Buy Now

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  Tips on Getting Quality Scan Data From Your 3D Scanner

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  Webinar – How To Combine Data from Different 3D Scanners to Improve Scanning Results

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  Webinar – 3D Scanning Small Objects with Amazing Results

The quality inspection process usually involves testing, checking, or measuring one or more product characteristics and comparing them against a standard (such as a CAD model) to determine if the product is compliant or not (pass or fail). If you feel that your current inspection process has its shortcomings—whether it’s not as reliable, accurate, or fast as you want it to be—now is a good time to take a closer look and see what a professional 3D scanner has to offer. The quality of your manufactured goods directly impacts how people perceive your company—good or bad.

It’s easiest to understand why you should consider switching to using 3D scanning for quality inspection by addressing the challenges you might be facing today.

1. If you are questioning whether your inspection process is reliable.

   

   Conventional methods of inspection (ones that are done manually) heavily relying on employees to carry out standard operating procedures or use hand tools such as calipers to take measurements off a part to determine if a part pass or fail. Even if standardized inspection documents are set in place, the way inspection is being carried out can vary from person-to-person. 3D scanners minimize errors by taking out the human element out of the equation.

   Much of the process of 3D scanning to inspection can be automated to eliminate manual work. This helps keep user interference to a minimum. Integrating a 3D scanner into the inspection procedure creates a repeatable process that can be trusted time and time again.

   

2. If you are questioning whether your inspection process is accurate.

   

   Honestly, no measurement tool is perfect. They all have a certain degree of measurement uncertainty but professional 3D scanners can be remarkably accurate (depending on the scanner’s specifications). Some can scan up to submillimeter accuracy. This makes 3D scanners an ideal choice for inspection applications.

   

3. If your parts are difficult to measure with other measurement tools.

   

   Some measurement tools like rulers, calipers, and CMMs are great measurement tools for measuring rigid or prismatic surfaces. However, there are some surface characteristics that non-contact 3D scanners excel at taking surface measurements. These type of surfaces include:

   • Complicated parts: Sometimes you have to take measurements of a part with organic surfaces, which can be difficult to measure with manual hand tools.
   • Small parts: Tiny parts can be difficult to measure due to their size. They can contain components that can be easily be damaged when handled (i.e. circuit boards). Non-contact 3D scanners don’t need to touch the object so it won’t cause measurement interference.
   • Parts difficult to carry to the measurement equipment: Some heavy components are too difficult to take to a measurement device like a traditional CMM. On the other hand, 3D scanners like wireless handheld 3D scanners and portable stationary 3D scanners make it much easier to scan by bringing the scanning equipment to the part.

   

   Previously, a known issue that 3D scanners have was taking measurements of dark or shiny surfaces (this is because they use light as a source for capturing 3D scans). Nowadays, technological advancement enables professional 3D scanners to overcome this challenge.

4. If your inspection process is slow at measuring parts.

   

   3D scanners can take measurements fast. Instead of taking one measurement one at a time, many non-contact 3D scanning systems can take an area of the object’s surface with more than 1 million measurement points in just under a second.

   The Artec Micro desktop 3D scanner captured a 1.5 cm plastic bolt in just three scans. The highly detailed 3D model highlights the bolt’s defects as well as its threads, making it an exceptional tool for quality inspection.

5. You want to get to the source of why your parts are failing.

   

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   Make Complex Challenges Much Simpler to Understand and Solve

   

   Sometimes it’s difficult to know where to start when given a complex measurement problem. 3D scanners equip you with comprehensive data. When paired with the right 3D inspection software, it can help you quickly to figure out the source of production issues. It provides a complete report to better understand the issue with the intention to significantly reduce downtimes in the manufacturing process.

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   See the Full Picture

   

   You can capture a snapshot of the part with measurement information with a non-contact 3D scanner. It empowers you to identify issues in its entirety at once instead of just seeing one aspect of the part.

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Other Considerations

Not all professional 3D scanners are designed for quality inspection. Resolution and accuracy of a 3D scanner are very important technical specifications to look at for this type of application. Talk with your 3D scanning provider to make sure you are choosing a 3D scanners are suitable for your specific application.

By implementing a 3D inspection process, you can:

• Have increased confidence your products are of high quality
• Speed up your manufacturing process
• Have less downtimes
• Be faster at solving underlying issues in your production process

As a result, your customers are happy because your company is putting quality products out in the market

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Reference:

1. Source: Science Focus, How small can the naked eye see?
2. This article is partly inspired by Artec and 3D System’s eBook, Is 3D Scanning Right for Your Inspection Needs? It goes into further detail about how to select the right 3D scanner and 3D inspection software.

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The short answer is no. A 3D scanner cannot directly output a CAD model. This is because a 3D scanner outputs point clouds or mesh data, which acts as a single entity that is not editable.

Let’s explain this concept using a camera as an example. A 3D scanner is just like a fancy camera, except instead of taking photos it captures scans of objects in 3D. If you take a photo of a car with a camera, you know that the photo has a car in it. However, your camera cannot interpret what exactly is in the picture. It only understands that the file is a picture. If you upload the photo into your computer to view it, likewise, the computer would only know that it is a picture, but not what the picture contains.

A 3D scanner is just like that. The computer program knows there is a scan but it has no idea what the scan is supposed to represent. You must interpret what the scan is. Then using CAD software on the computer, you sketch the object into a CAD model using the scan data as a tracing guide. Just like if you want to draw a realistic drawing of a car, it would be much easier to directly trace right on top of the photo than if you have to draw it from memory or just by looking at a photo.

Using scan data from a 3D scanner as a reference for design creates incredibly accurate CAD models. This process is known as Scan to CAD. You need this modeling step to bridge the gap before you can have a CAD model consisting of a solid CAD model with editable features, the design blueprint of the product for manufacturing.

This sounds rather complicated. Can you show me the Scan to CAD process?

It’s actually not too complicated once you understand the basics. Sometimes it’s easier to explain this with a simple demonstration. In this video, scan data was imported into SOLIDWORKS CAD modeling software. Mesh2Surface for SOLIDWORKS plugin that works natively inside the CAD modeling program was used to reverse engineer the part.

Point cloud or mesh output by the 3D scanner provides pertinent surface measurements about the object’s surface geometry which is useful in creating a CAD model of the part. The scan data functions as a template in building the new CAD model.

Once you go through this modeling stage, your output is a CAD model (STEP or IGES) which is now ready for manufacturing.

Then why use a 3D scanner to create a CAD model if I have to recreate it anyways?

Designing from a blank canvas can be an overwhelming project to take on. You might not get it right on the first try and may take you many versions to get you to the final CAD model you are happy with. Why not leverage knowledge from an existing object and learn from it which will make your work much easier and more accurate?

Reasons why to Scan to CAD:

1. It’s more efficient than designing from scratch
2. It gives you an accurate representation of the existing part to create the CAD model
3. It gives you the ability to insert design intention and fix problems or damage

Creating CAD models through the process of reverse engineering from Scan to CAD gives you insights into designing better products but also do it in a faster amount of time than designing from scratch. This is especially true for objects with organic surfaces. A 3D scanner makes reverse engineering faster and much simpler than if you have to do it without aids. Instead of trying to get complex curves and angles just right, reverse engineering gives the user the ability to snap onto the curve and create an identical profile. If the profile is incorrect or the physical part has any damage, then the designer has the power to see where the old geometry is and has the ability to correct it.

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