Import File command

Use the Import File Dialog Box to read a CAD interchange file of STL or DXF type into L3DD.  If the 3D View already displays an object, the CAD file will be added to it, otherwise you must first clear the view by issuing a New command.  Objects that are to large to be imported in their entirety will be partially imported by L3DD.  See Limits.

The Import File command invokes a dialog box similar to the File Open Dialog Box.  The ‘CAD Files’ directory is normally visible first up.  Choose an STL or DXF file to open.  If the file can be successfully opened and read, its contents will be automatically displayed in the 3D View, which is automatically scaled to fit the object.

STL files are ‘stereolithography’ files used in rapid 3D prototyping and manufacturing.  They are simple ASCII files listing triangular faces that define a computer-generated solid model.  They are reasonably reliable, and can be exchanged with many CAD programs.

DFX files originally belonged to DeskView’s AutoCAD®, but they are now widely used as CAD exchange files.  L3DD implements only a small subset of the data types supported by DXF files, but it will read 3D faces, points and lines.  No colours or textures are imported or exported, only the basic 3D geometry.  Other data types are ignored.

The 3D faces in ST and DXF files each have their own sets of vertices, but the faces can be joined with the Join Faces command in the Tools menu.  DXF faces are llimited to 3 or 4 vertices, so faces in L3DD that have more than 4 vertices are made up in imported DXF files of two or more co-planar tessellated faces.  Common edges are rendered invisible, so that in ‘Wireframe Mode’ the object will appear to be without tessellation.  However, the tessellated faces can be seen in ‘Solid Mode’ with the help of the ‘Multicolor Décor’ option.  If tessellations are a problem, they can be edited out manually.

The illustration shows a soccer ball imported from a DXF file, in which each hexagonal and pentagonal face is made up of two tessellated faces.

Copyright © Ligno3D Systems, 2006