IndiaCADworks’ Best Practices in MicroStation® Conversion
Many messy problems have to be dealt with when CAD files are translated between AutoCAD® and MicroStation®. A few of these problems are:
- Incorrect working units, resolution, and dimensions between 2D and 3D objects,
- Incorrect size elements which may have incorrect coordinate locations,
- Incorrect element color and weight,
- Incorrect line styles,
- Incorrect fonts.
In order to correctly translate CAD files between AutoCAD® and MicroStation®, IndiaCADworks’ MicroStation® Conversion Team understands design practices for storing and displaying CAD data are different between the two systems. Once these changes are understood, many of the messy translation problems can be overcome by using options, which are available for opening and saving CAD files between the two systems. The unpleasant translation problem between the two systems has led to the development translation software. However, a perfect automated translation system has yet to be found. Therefore, the IndiaCADworks engineer (referred to as the CAD engineer) understands why translation problems exist and how to fix them.
In this article, we shall review some of the best practices and techniques that IndiaCADworks uses to perform smooth CAD file translations between AutoCAD® and MicroStation®.
Converting from MicroStation® to AutoCAD®
IndiaCADworks facilitates translations between AutoCAD® and MicroStation®, while maintaining CAD standards, on the basis of two facts.
The first fact is that information is stored and displayed differently in the two programs. For example, many versions of MicroStation® store line properties (color, weight, style) independently of the level in which it is placed. On the other hand, AutoCAD® assigns line properties to a named layer. The second fact is that MicroStation® and AutoCAD® use different methods to create and store files.
Because of these two facts, translations between MicroStation® and AutoCAD® follow these guidelines:
- When an AutoCAD® file is opened in MicroStation® as a DWG file, all required changes and settings are made in the “DWG Open Options”. Some of the settings include background color, units, resolution, and others. It is necessary to make these settings while the DWG file is stored in memory, before it is saved as a MicroStation® DGN file.
- Before saving the DWG file as a DGN file, set the required resolution for MicroStation® by selecting the appropriate “DGN Seed File”.
- If the output DGN file should be in 2D rather than 3D, turn on “Create 2D models for Model Space/Paper Space” in the “DWG Open Options”.
Translating from MicroStation® to AutoCAD® should use the “Save Design As” option, and should use the “File, Export, DW” options. However, complex shapes, custom line styles and line weights will not translate directly. The reasons are explained in the next section.
Getting the Line Weights Right
As mentioned above, working units should be set in the “DWG Open Options” of AutoCAD® before writing DGN files for MicroStation®.
The reason why line properties (color, weight, style) do not translate easily between the two systems is due to the different ways line properties are handled.
- MicroStation® stores line properties in resource files, which are loaded when MicroStation® starts. On the other hand, AutoCAD® stores line properties within the drawing and associates the properties with a defined layer. The CAD engineer provides a table for converting named layers to levels and vice versa.
- The default color map is different between AutoCAD® and MicroStation®. The CAD engineer provides a table for converting between the two color maps.
- The default number of layers or levels for line styles is different between AutoCAD® and MicroStation®. MicroStation® supports 63 levels for line styles, while AutoCAD® supports unlimited layers. Default font settings are also different for the two systems. The CAD engineer provides tables for converting between lines styles, line weights, and text fonts.
- For correct rendering, the CAD engineer provides a weight for the color map or table.
Resolving Text and Other Issues
Because default text settings for the two systems are different, the CAD engineer provides a table for converting between the two font systems. Basic single line elements in MicroStation® do not have text line style properties, and they will not convert properly into AutoCAD®. In order to convert properly, the MicroStation® file should use the multi-text mode.
By default, AutoCAD® works in 3D. If a DWG is to be translated into a 2D DGN file, turn on “Create 2D models for Model Space/Paper Space” in the “DWG Open Options” before writing the output DGN file. However, conversion of solids and patterns from MicroStation® to AutoCAD® is still problematic. AutoCAD® treats solids and patterns as objects, while MicroStation® does not.
The Choice between Conversion and Redrawing
Unpleasant tasks that should be performed when CAD files are translated between AutoCAD® and MicroStation® suggest that a certain amount of redrawing is required after file conversion. The amount of redrawing required depends on the efficiency of the conversion, and therefore on the skills and experience of the CAD engineer who performs the conversion.
IndiaCADworks’ best practices include (a) limited automatic batch conversion, (b) experienced-based conversion, and (c) redrawing. This provides an efficient, balanced, and cost effective method for performing conversions which are compliant with CAD standards.
