3D Scanner beginners guide
When it comes to printing in 3D it is very likely that we design our own 3D models or download them from the network. But what if we want to print an exact copy of an object from the real world? This is where the 3D scanner comes into play .
What does a 3d scanner do
A 3D scanner is a tool that allows us to obtain a digital model of an object from the real world. This is really useful when we want to work with very complex objects, immortalize sculptures or design pieces that are going to go over people. The use of 3D scanners is becoming more common in the world of prosthetics and orthoses . With this it is achieved that these adapt perfectly to the patient.
How a 3d scanner works
Talking about 3D scanners is like talking about 3D printers, we have different techniques that can help us achieve the same result, each with its pros and cons. The most used for 3D printing are:
The Photogrammetry is a technique of obtaining a 3D model from photographs.
To use this technique we must first photograph the real model from all angles and possible positions to obtain the maximum possible information of the object. With these photos, a software will look for common features in all the photos to build a 3D model.
Thanks to the use of drones with this technique we can scan large objects, such as buildings. If you want to try some software without doubt 123D catch autodesk.
With this technique, a laser is emitted on the object to be scanned and then the angle of the laser reflected in the object is measured. These measurements can be transferred to coordinates with which a 3D mesh will be generated later .
Scanned by structured light
It is a method similar to the previous one, but this time instead of a laser a light pattern is emitted on the object to be scanned. By measuring how the light pattern deforms when it comes into contact with the object, a digital replica of it can be created .
Recommendations when scanning in 3D
Whatever 3D scanning technique we use, there are a number of things we have to take into account to obtain quality models.
1.- Avoid reflective or transparent surfaces
Whether we use techniques by light or photogrammetry , transparent or reflective surfaces are a big problem.
In the case of photogrammetry the problem is in the way in which the software will interpret our photos. The software of photogrammetry will assume that all surfaces of the object to be scanned are the same and do not understand if what you are looking at is the front part or a transparency.
In the case of light , the transparent or reflecting surfaces will distort the light pattern or the emitted laser, which will confuse the program when calculating the coordinates of the object.
A good practice, if possible, is to paint the piece to be scanned with some dark matte color. This will give us a uniform surface that the program can reproduce perfectly.
2.- Controls the ambient light
To obtain the best results by scanning in 3D it is important that the piece to be scanned has uniform illumination . In this way we will avoid shadows and reflections that may confuse the scanning software.
It is preferable, if we do not have lighting equipment like the one used in photography, to scan outdoors better than with artificial light. A good time to scan is a cloudy day, since we will have a uniform light avoiding flashes.
3.-The position of the scanner on the object
Whatever technique we use, we will have to scan the object from all directions . To rotate around the object we can use two methods. Either we rotate the scanner on the object, or we rotate the object leaving the scanner static.
It is preferable to rotate the object on a rotating surface that moves us, since a bad pulse can affect the quality of 3D scanning . This is not always possible, so if you have no choice but to rotate the scanner slowly avoiding sudden movements and vibrations.
Advanced photogrammetry equipment consists of a dome of cameras that surround the object to be digitized and shoot automatically at the same time . In this way they make sure to get the photos always with the same light and from all the important angles.
And you have any experience using 3D scanners? Share it in the comments
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