Scanning Basics - 3D Systems Geomagic Capture Series User Manual

4 3D SCANNING BASICS
Scan Quality
Scan quality can vary by the following factors:
• Environmental conditions
Light and vibration can cause inaccuracies. Ensure that a scanning environment is stable and the exposure is set according to the
current conditions.
• Stability of the scanner and an object
If either the scanner or the object move during the scan, the data will be inaccurate. Ensure both are stable and secure.
• Shape and size of an object
Target markers or reference spheres should be used in order to align scans correctly if the part to be scanned has limited fea-
tures.
Scan Preparation
When you set up the scanner, you should:
• Understand how the scan data will be used
This determines the mechanics of the scanning process and which features, if any, should be hard probed.
• Know who will use the scanned image and what they will need captured
This eliminates unnecessary work and potential rescanning.
Scanner Positioning
When positioning the scanner to acquire the most accurate data, consider the following items:
Scanner position
•
Positioning the scanner perpendicular to the surface being scanned optimizes the amount data the scanner collects. When the
data is at an angle, the light can fade out as it goes farther back and the data becomes less accurate. Also, when you are de-
termining how to position the scanner and object, place the scanner so it can capture as much of the object as possible while
remaining perpendicular to the object's surface.
• Line of sight
The scanner can capture only what is in its line of sight. If you scan a propeller, for example, it will need to be placed so that the
scanner can capture the curve of the blades and in between the blades. If the part needs to be held at a particular location, you
must decide the best method for holding the part while scanning. Any solution should allow you to fully capture the part in one
setup to minimize the amount of repositioning.
• Scanner volume and area
The scanner will have a defined area that can be captured. A large part may require several scans to capture all sides and then
will be aligned together by alignment methods provided in Geomagic Capture application. Each scan needs to overlap the previ-
ous section to be able to align them together or there needs to be common targets on each scan set for alignment. Be sure there
are enough features to align the data.
Part Preparation
Before scanning there are two steps for part preparation: placing reference target markers on the part and coating the part.
Placing Target Markers
For parts that have little geometry or are as big as insufficient in a scanner view range, place target markers on the part in order to
use these features during alignment.
Scanning with target markers provides a faster and more convenient way of aligning multiple scans since the alignment algorithm
is greatly speed up by having far fewer reference points to search for and match up.
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