Import STL File dialog box

Used to read stereolithography (STL) files into MicroStation. STL files are basically lists of triangles.

Opens when you select a file to import, after you choose Import > STL from the File menu.

The simplest import methods (None: save as Mesh and None: save as Shapes) import each triangle as a MicroStation shape, while the advanced methods (Decimate, Smooth Surface, and Decimate then Smooth Surfaces) provide more data compression.

Import STL File dialog box

Simplification Methods

Provides options for importing the data.

• None: save as Mesh
— (Default) Stitches the triangles together, performs some minimal processing to remove duplicate and/or degenerate triangles, and outputs the triangulation as a MicroStation mesh element. Mesh elements are an efficient way of storing faceted geometry.

• None: save as Shapes
— Performs no simplification. Each triangle in the STL file is imported as a MicroStation shape element.

• Decimate
— Stitches triangles together, then selectively collapses triangles in a way that preserves local volume. The resulting triangulation is output as a MicroStation mesh element.

This method is effective for importing STL files that represent curved shapes.

To increase decimation, key in a larger number of degrees in the Sharp Edge field.

• Smooth Surfaces
— Stitches triangles together, then merges the triangles into possibly punctured planar shapes, output as MicroStation shape, ellipse, and cell elements. In addition, this method recognizes cylindrical/conical objects, and outputs them as MicroStation cone or surface elements.

This method is effective for importing STL files that represent objects with many flat surfaces.

To increase the aggregation of triangles into larger shapes and surfaces, enter a larger value in the Merge Tolerance field.

• Decimate, then Smooth Surfaces
— Applies the Decimate method, then the Smooth Surfaces method.

Merge Tolerance

(Smooth Surfaces or Decimate, then Smooth Surfaces methods only) — Controls the aggregation of triangles into larger shapes and surfaces. Key in a larger value to increase the aggregation of triangles. Adjacent triangles are considered coplanar if they have normals that span a radian angle whose square is smaller than this tolerance.

Sharp Edge

(Decimate or Decimate then Smooth Surfaces methods only) — Controls decimation. Key in a larger number of degrees to increase the decimation. An edge will be preserved if the adjacent triangles' normals span a larger angle.

Generate Report

If on, import statistics are output to the Text window. These statistics include the following face/triangle reports: raw, imported, output, and savings. For most simplification methods, various topological counts are also reported.