Cloud tool overview

Despite all the advances in modeling directly from concepts and criteria, it is still often necessary to digitize existing 3D models and transfer that point data into the computer so that it can be used as part of the design process. This is especially necessary when free-form shapes are involved. Traditionally, 3D point data from existing models was acquired solely through touch-probe coordinate measuring machines (CMMs), which run at a rate of no more than one point per second. In recent years, it has become useful to acquire 3D points using optical measurement sensors. These types of sensors can measure points without touching the physical object, at rates up to 10,000,000 times faster than touch-probe CMMs, with most current commercial 3D scanners running over 1000 times faster. The entire surface area of an object can be digitized very quickly without even touching it, creating a virtual 3D copy of its shape in the computer.

The following image shows a two-arm CMM with a touch-probe tip digitizing a single point on a portrait sculpture, and a laser scanner digitizing a complete scan line with 500 points.

The problem with the new laser scanner technology is that most design software cannot accept the huge amounts of data produced by the scanners. File sizes range from 120 kilobytes for 10,000 points to 120 megabytes for 10 million points or more.

Note: Typically, each point requires at least 12 bytes of information, so multiply the number of points by 12 to determine the total number of bytes that a point data set requires.

Not only is file size a concern, but cloud data points are not usually ordered in any specific way to make them directly useful in applications.

To further compound the problem, there are currently no standards for portable binary data file formats for cloud data. That is, there are only a few text file formats, such as IGES, VDAFS, or simple ASCII XYZ, which cause files to occupy 2.5 to 7 times more disk space than comparable binary files containing the same information. They also take about 6 to 12 times longer to read or write. As a result, each 3D scanner vendor tends to have its own binary format for point data.

EvalViewer provides the following functions to make cloud data useful to you:

Cloud input from many different binary vendor-specific file formats. For more information about these formats, see File menu.
Cloud input from four different generic point formats (IGES 106 Copious Data, IGES 116 Points, VDAFS PS/PointSet, generic ASCII XYZ/RGB, ASCII XYZ / 3 coordinates per line of text). These options provide additional input capability from Digibotics, 3D-Scanners, Laser Design, Lemoine, and almost all other scanners.
Cloud input from Alias wire files
Cloud input from Alias Pix, SGI RGB, or JPEG/JFIF, so that 2D paint packages can be used to create Intensity = Depth surfaces
Cloud output to IGES 106, ASCII XYZ, or Alias wire file
Line/section output to IGES 106, DES, DXF, or Alias wire file
Polygon output to Wavefront OBJ, STL (stereo lithography format) (ASCII or binary), Inventor, DXF, Unigraphics FAC File, Alias (object-separated) triangle file, or Alias wire file
Cloud quick render, view mesh or voxel mesh shaded image visualization
Cloud XYZ cross-sections: direct cloud processing or via view or voxel meshes
Cloud to polygons conversion: quick render, view mesh or voxel mesh polygons
Cloud to reduced polygon count models via view meshes or voxel meshes
Cloud to lines conversion
Line and polygonal data conversion back to cloud
Line editing tools: delete point, line, break, join
Line smoothing filters
Line chordal deviation point count reduction
Line resampling (uniform by point count or segment length)
Support for arbitrary line/radial sections
Support for Interactive feature line definition
Do plane fit, sphere fit, or surface fit to unstructured cloud data.
Fit B-spline curves to lines for reverse engineering applications using hull fit or standard least squares.
Build quick polygonal and NURBS surfaces (via skin or square) using line data to test the quality of the cloud data sections.
Compute a color error map or deviation vector plot of the distances between clouds and other objects, such as polygon meshes created from other clouds or CAD surfaces that specify the idealized shape of a part.

All these functions are in a Studio-like 3D viewing environment with a fixed set of tabs along the bottom of the graphics window to allow quick access to the various tools.

Please refer to the sections in the remainder of this document. You will find a section on Using EvalViewer as a Cloud Tool as well as an EvalViewer Reference section describing all Menu Picks and Tab Buttons. Other relevant sections include a HotKeys Summary, Frequently Asked Cloud Data Questions, a Glossary, and a List of Supported Scanner Vendors for EvalViewer.

Next: Surface evaluation tool overview

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