Stratasys Objet30 User Manual page 23

Objet30 User Guide
Source Files
PolyJet printing systems produce three-dimensional models designed with
most CAD tools and some other 3D applications. Supported file formats:
• STL
• SLC
Objet30 systems feature the capability of producing different types of model
files simultaneously.
STL is short for Standard Triangulation Language. This language views any
STL Files
object as a collection of surfaces, and describes each surface of the object as a
collection of triangles.
For example, a square can be described as two triangles; a cube (six squares)
as 12 triangles. Curved surfaces need more triangles to describe them. The
higher the tolerance (for smooth surfaces), the more triangles are needed.
The result is that high-quality object descriptions mean very heavy files.
Most CAD software can export STL files. The Objet30 system utilizes these
files for building models (rapid prototyping), and also for directly making
molds for mass-producing items.
STL files can be ASCII (text) files or binary files. The content of the ASCII file
begins with "solid" and ends with "end-solid" (both lower case). Between
these keywords is a list of the triangles that describes the faces of the solid
model. Each triangle defines a single normal vector directed away from the
solid's surface, followed by its X-Y-Z coordinates. These are expressed as
Cartesian coordinates and are floating-point values. The coordinates of all
triangles should be positive and should fall within the volume of the model.
SLC is short for Stereo-Lithography Contour. SLC files describe two-
SLC Files
dimensional contours of the three-dimensional models. These contour lines
are polylines.
SLC files are ASCII (text) files that save models as a series of slices. This
means that models based on SLC files cannot be orientated; only their scale
(size) and position on the build tray can be controlled. For this reason, the
model's orientation must be suitable for production before it is saved as an
SLC file. Because of the nature of SLC files, the appearance of models in Objet
Studio may be different than the solid-object images displayed from STL files.
DOC-34022 Rev. D
3 Introducing the Objet30 3D Printing System
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