Translation Process

Within the STL format all objects are represented by triangles, the triangle being the shape with the minimum number of sides that can be used to represent a three-dimensional object. Unfortunately, reducing a shape to triangles increases the quantity of electronic data necessary to define the shape.

For example, a square drawn in a CAD system is defined by its four corners or vertices. The same square in STL format is represented by two triangles, each triangle having three vertices, totalling six vertices, representing a 50% increase in data needed to define the square.

Taking this analogy a step further, a cube within a CAD system is defined by its eight vertices. The surface of the same cube in STL format is represented by 12 triangles, two for each of the six faces of the cube, each triangle having three vertices, totalling 36 vertices. A 450% increase in data is needed to define the cube.

Shapes within a CAD system more complex than a cube result in even greater data increase factors. It can therefore be seen that STL files can be very large in terms of data volume or file size. There are two main effects:

• Large STL files may take several hours to map into Model.

• Highly detailed models in Model may drag down the performance of the computer and are slow to manipulate.

It is very important that the detail in the source CAD file used to generate the STL file and the amount of detail required in the Model should be considered very carefully.

It is impossible to give any definite instructions as to what should be done as there are too many possible combinations of source CAD systems and Model uses to define parameters for. The most suitable combination of parameters and settings is best determined by trial and error, however, the following guidelines may be useful:

• control the quantity of STL data

• control the quality of STL data

• control the translation

• review and improve the DESIGN model.