Control the Quantity of STL Data

AVEVA ImPLANT-STL processes STL data intelligently, attempting to recognize groups of triangular facets that equate to particular standard shapes defined in PDMS/Outfitting as primitives (box/cylinder/pyramid/extrusions and negative versions of these). Facet data that cannot be mapped to any of these primitives is dealt with by creating the facets as POHE (polyhedron) primitives, a less efficient form of handling the data. If, however, the 'solid polyhedron' mode is used (see below) and ImPLANT-STL recognizes a solid then this is more efficient.

A good indicator of a successful operation using ImPLANT-STL is the quantity of POHE primitives within the resultant model. The fewer the number of POHEs the easier it is to manipulate the data in DESIGN and drafting modules.

There are therefore two factors that directly affect the performance of model manipulation in DESIGN. These are:

• The ability of ImPLANT-STL to recognize and map triangular facet groups to PDMS primitives.

• The quantity of data to be translated.

It is a good working practice to minimize the amount of data that needs to be translated; this can be done by applying the following guidelines:

• Remove all non-essential aspects of the source model, eg in the case of a gearbox, export the gearbox casing but not the gearbox internals.

• Remove or disable features in the originating Mechanical CAD System that automatically generate many curved surfaces, such as fillets and chamfers. Some Mechanical CAD Systems allow these features to be disabled temporarily, while the export to STL file operation is in progress.

• Use an appropriate tolerance setting when exporting to the STL file. It is impossible to stipulate an exact tolerance setting since this depends very much upon your requirements for the DESIGN model. The looser the tolerance factor setting the less accurate will be the resultant model and vice versa. The recommended approach is to start with a loose tolerance setting, inspect the resultant model, and re-import all or part of the model at a tighter tolerance setting, as necessary.