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A survey of advantages and disadvantages of 3D model methods

A survey of advantages and disadvantages of 3D model methods


When deciding on what type of 3D modeling to use, we need to think about the result we are aiming at and what drawbacks and benefits it brings to us. There are two general streams for drawing 3D models. First, Computer-Aided-Design or CAD, which includes much comprehensive software, and second, 3D scanning, looks at two different types (non-mobile and handheld 3D laser scanners).

When deciding on what type of 3D modeling to use, we need to think about the result we are aiming at and what drawbacks and benefits it brings to us. There are two general streams for drawing 3D models. First, Computer-Aided-Design or CAD, which includes much comprehensive software, and second, 3D scanning, looks at two different types (non-mobile and handheld 3D laser scanners).

Computer-Aided-Design (CAD)

Computer-Aided-Design or CAD involves using a computer to create, modify, analyze, and optimize the model of an object or apart. It is used quite extensively in industrial and manufacturing environments. There are many types of 3D modeling software, and we’re going to take some examples of the most popular ones: Sketchup, Blender, AutoCAD, Rhino, Revit, 3Ds Max, Maya, Cinema 4D. All these software have some positive and negative points to draw 3D models. 



Advantages

  • High precision, low error 
  • Designs can be viewed from all angles and with a range of materials
  • Automating the design process
  • Saving time
  • Simulation
  • Re-use and share
  • Easy to make changes
  • Ideas can be drawn and developed quickly
  • Some testing and consumer feedback can be done before costly production takes place

Disadvantages
Work can be lost because of the sudden breakdown of computers
Work is prone to viruses
Work could be easily “hacked.”
Time taking process to know how to operate or run the software
High production or purchasing cost for new systems (hardware, software) and training
Need of regular updating of software or operating systems

Although, when CAD service is outsourced, most of the above disadvantages will be overruled. For instance, the need for train resources is eliminated. There would be no need to purchase hardware or update CAD software at regular intervals.

3D scanning 
Different types of 3D scanning methods and the principles they are based on are as follows:
Laser-based 3D Scanners, Photogrammetry, probing.
This article looks at the pro con of the first method, which has two different kinds of devices: non-mobile 3D scanners (industrial) and handheld.

Industrial 3D Scanner


A laser scanner has a sensor that collects information from a laser that goes over the object’s entire surface.  This process provides a digital triangulated mesh of the object, which then can be opened up in CAD software for remodeling, repairing, and customizing.

Advantages of Non-Mobile 3D Laser

1. Fast & Thorough
2. Accurate
3. No-contact 
4. Cost-Effective 
5. Safe

Disadvantages of 3D Laser Scanning

1. Scanners can only read at the surface level
Given the optical nature of 3D laser scanning, it is impossible to measure any surface out of the scanner’s line of sight. This means that hidden or internal geometry that is not visible to the scanner cannot be calculated. Scans are taken from many different angles to ensure a complete model. However, complex geometry may still prove to be a problem, such as it commonly occurs with holes or threads. For measuring objects with hidden geometry, we recommend using a CT scanner instead. 

2. Scanners can’t successfully scan transparent or reflective objects
Because 3D laser scanners read the light of a laser to record data, ambient light may blend with the laser and interfere with the scan’s accuracy. Depending on the severity of this interference, the scan may be noisy or even unusable. It is recommended that parts be scanned in a separate room where lighting can be monitored and controlled. For outdoor use, superb scans may be more challenging to obtain due to various weather conditions, including ambient temperature and humidity.

3. Initial Cost
Industrial 3D laser scanners can be quite expensive. On average, it costs from $50,000 to $150,000. This does not include set-up accessories or operator training. Training a worker to operate the scanner and software and turn the scan into a usable model is expensive. 

4. Scanners can’t determine the material they are scanning
The next obstacle is choosing the material in the scan.  This may be more important in the future for reverse engineering or selecting the mixture materials used to design a new version of products.


Handheld 3D Scanners
handheld 3D and their software (which is often the most complex part of the process) are becoming much easier to use, with smoother workflows and improved design and ergonomics.

Advantages of handheld 3D Scanners
1. Ability to access hard-to-reach places
2. Relative ease of use
3. Portability

Disadvantages of handheld 3D Scanners

1. Lack of precision
The human in charge of scanning objects must remain still and retain the same amount of distance from the object at every point of data gathering. While it may save money to invest in a handheld scanner instead of the expensive non-mobile option, the outcome of the scans and resulting clarity of images you have to work with will not be as high-quality as you might hope.


2. Lack of clarity
In the same vein as precision, clarity in reverse engineering gives you a better vision of the product you are looking at manufacturing, analyzing, or deconstructing for improved modifications. When an unsteady scan gives you imprecise digital data, your inspections and research findings will be skewed, and the work you hoped to avoid, such as multiple iterations, will resurfac


3. Human Error
Sometimes if objects are small, handheld devices may seem like a quick option and cheaper solution. However, when the time comes to scan a huge object, this would take an extremely steady hand and a patient person to complete the task. Human error, while unintentional, is often unavoidable and can cause unnecessary stress.

4. Instability
Like we mentioned above, it would take very close attention to detail and much time to gather all the data necessary for large objects. When humans are behind the scanner, it could result in missed data points or unclear digital data because of slight movements either closer or farther away than where the scanning began. It’s only natural for arms to become unsteady after a certain amount of time, and the 3D scanner could lose the sense of depth it was originally calibrated to read.

5. Scan time
Handheld 3D scanners require a human to be present to hold the scanner and cover every data point to read all measurements that consume a lot of time and effort.

Conclusions
Since each method has its limitation, experts and engineers have studied to propose the most effective approach to create accurate 3D models.