Tech Briefs

Point Cloud Data

Three dimensional scanning is typically used in biomedical applications (CT scans) and in reverse engineering of existing objects (to study the characteristics and/or improve the design).

When scanning an object, the end result is a collection of points on its surface (assumed to be dense enough and without noise). If a finite element analysis is to be performed of the object, this cloud of points must be processed to obtain a solid model (in discrete form) where the inside is clearly separated from the outside. This is achieved through the process of automatically "sculpting" the elements away from the convex hull to obtain the correct shape. The final object is then fully described by a triangular surface mesh whose vertices are the scanned input points and which can be saved as an STL file.

This option is available in ADINA 8.6. The STL file can then be loaded into the ADINA User Interface (see News of Dec. 15, 2008) to obtain a three-dimensional tetrahedral finite element mesh at the desired mesh density.

Figure 1  Input: point cloud obtained from scanning device.
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Figure 2  Output: STL format file (seen here loaded into the ADINA User Interface).
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This ADINA option to convert point cloud files into STL files is an important feature, in addition to existing interfaces available, for the analysis of scanned objects.

Stereolithography, STL file translator, CAD import, rapid prototyping, point cloud, scanned data.