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How to convert STL (StereoLithography) to DGN (MicroStation)?

PolyTrans|CAD+DCC performs mathematically precise CAD, DCC/Animation, GIS and BIM 3D file conversions into all key downstream 3D packages and file formats. Okino software is used and trusted throughout the world by many tens of thousands of 3D professionals in mission & production critical environments, backed by respectable personal support directly from our core development team.

STL

STL (StereoLithography) is one of the industry's oldest (and simplest) 3D file formats created back in 1987 for 3D Systems' first commercial 3D printer. It is widely used for rapid prototyping, 3D printing and CAM. Okino has provided one of the very first and still primary STL export conversion systems for close to 3 decades.

Please take note that there is no 3D file format which is much simpler than STL. It is not a high-end, high fidelity 3D conversion file format as many people have come to wrongly believe. Rather, STL defines just a raw triangulated polygon mesh with no smoothing information (vertex normals), no uv texture coordinates, no assembly hierarchy part naming or any material assignments. 3MF and VRML2 are often much better file formats for moving 3D datasets into downstream programs and/or 3D printers.

The Okino STL exporter WEB page provides good graphical tutorial about how to convert CAD file data into STL and also how to clean a 3D model which is 'almost water tight'.

DGN

DGN is a 2D/3D file format, with its roots going back to the early 1980s, that is used as the native file format of such programs as Bentley's MicroStation and Intergraph's PDS software packages. Relative to deep history, DGN could be considered a competitor or rival to the Autodesk DWG file format. Okino considers both DGN and DWG rather "crude" and old file formats, depending on what vintage of file is used and whether the files contain ACIS-SAT/Parasolid "BREP solids" geometry or just 2D/3D vector geometry.

Okino considers a DGN V8 file to be of two varieties: (1) "GIS" like models defined using basic primitives like lines, curves, arcs and 3D objects defined by the extrusion and revolution of these basic elements - these types of files are typically glutted with an enormous number of basic elements which can result in massive scenes that can very slow to display and take up a lot of memory. (2) The second variety of DGN file uses the more modern "BREP solids" geometry type to define the 3D objects as lighter weight and more efficient NURBS surfaces and solids.

Okino spent over 20 years developing its DGN importers and exporters. As such, we understand the nuances of DGN and its related conversion issues. Please refer to our DGN importer WEB page which has extensive information on (1) the history of DGN and when to use DGN, (2) how to import massive DGN files (such as PDMS 3D plants, oil refineries, etc), (3) how to import from AVEVA PDMS and Intergraph PDS, and (4) our suggestions about using STEP or VRML2 as alternative conversion methods from Bentley's MicroStation.

How to Convert CAD to STL

STL import converter's overview

DGN export converter's overview