Command: Write

This command writes geometry, pictures, or other data into a file, from which it may later be read.

Note: writing a file may fail if you don't have the authorizations to write in the chosen model directory. Another possible reason can be that the file system is full. The authorizations may be checked with command DIRECTORY: INFO. The available disk space is seen with the UNIX command "df", issued in a command window.

As a parameter, the command asks for the type of file to be written. The possibilities are:

Model (identifier geom)

Writes all of the model geometry (under root) into a model file. This is the best way to save your models permanently.

Object (identifier cobj)

Writes only the target object, e.g., a curve, into an object file.

Picture (identifier xwpic)

Stores the contents of any window on the screen or selected parts of the graphics window into an image file. Which window or window part to store is selected as parameter, and/or shown with the mouse.

Primitive

Stores a surface into DeskArtes's extendable primitive library, user_primitives. It can later be conveniently restored from there with the command SURFACEÞDesign:Primitive, or read normally as an object file.

For storing the primitive, the system asks if the model should be scaled into the unit box or not. Scaling into the unit box is useful if the primitive should later be used in variable scales.

Data transfer

Various data transfer formats are available to move geometry to other CAD/CAM and Desktop Publishing systems.

The available data transfer formats are:

-> IGES (identifier igs)

Writes the contents of the target object (curve, curve set, surface, element, or root) into an IGES file. This is used to transfer data into other modeling systems, e.g. for CNC machining. Version 5.0 of the IGES standard is supported.

The command writes everything under the target object to the file. To write only surfaces, for instance, you may first gather them into one element with command SELECTÞCollect:Actives.

As parameters, the command first asks for the file name.

The second parameter gives a choice of optional flags. The optional flags can be used to define which information is not required to be written to the IGES files. With the default choice such flags are left out. Which choice to use depends on the flavors of the receiving CAD/CAM system, but it usually does not make any difference at all.

The third parameter, surface representation, gives a choice of outputting the surfaces as Parametric Splines, or Rational B-splines (NURBS): The latter alternative (Rational B-splines) is generally recommendable, as it makes the data transfer file size much smaller than the Parametric Splines.

The fourth parameter gives a choice of trim representation. It has two alternatives: Polylines, and Splines. The Polylines option outputs all trim curves as linear polygonal curves, while the Splines option converts all trim curves into smooth parametric curves. Many receiving systems seem to prefer having the trim curves defined as polylines, but not always.

The last parameter, spline trim tolerance, specifies how accurately the conversion from polylines to splines should be done if the Splines alternative of the previous parameter is used.

-> VDA-FS (identifier vda)

Writes the contents of the target object (curve, curve set, surface, element, or root) into a VDAFS file. Version 2.0 of the VDAFS standard is supported.

Other details with using the command are similar to IGES output.

-> DXF (identifier dxf)

Writes the content of the target object into a DXF file, as with IGES and VDA-FS output above. Version 11.0 of the standard is supported.

The DXF standard is mainly used to transfer data into 2D drafting systems. The standard can also define faceted surfaces and even parameteric surface descriptions, but not surface intersections.

The command asks for the following parameters:

-> SGI Inventor (identifier iv)

This outputs the selected faceted model in the SGI Inventor format. The shading colors assigned to the models will be transported, too. The option is available only with Silicon Graphics operating systems IRIX 5.x (or higher).

-> PostScript (identifier eps or aps)

Writes a 2D object (curve, polyline, set of curves, text etc.) into a PostScript file.

Two slightly different PostScript flavors are available, and can be chosen as a parameter: Encapsulated PostScript (eps) and Adobe Illustrator PostScript (aps)

Note: The PostScript preview image is not included in the output file.

Rapid Prototyping

The following data formats are specific to transporting data to Rapid Prototyping, as well as some Analysis and Manufacturing systems.

-> STL (identifier stl)

Writes a faceted model or an element of those into the .stl file. DeskArtes asks, whether the data should be stored in ASCII or binary format.

Note that the model should have no holes, and its normals should point into the same direction, if it is to be manufactured. The same rules apply to the creating solid faceted models as with command DIMENSÞFaceted:Volume.

-> Slice (identifier slc, cli or sli)

Writes a set (element) of planar 3D polylines into a slice file format, specific to different rapid prototyping systems.