DWG Compatibility in MicroStation® V8 MicroStation V8 "seamless DWG" is good, but not good enough

Issues Investigated Visual Fidelity Performance Model-Based Design Information Precision for Shared Data File “Save As” Sizes

Visual Fidelity Viewed in AutoCAD 2002 Viewed in MicroStation V8 Significant visual fidelity differences Significant visual fidelity differences Difference in viewing an AutoCAD sample file –A common AutoCAD file with basic entities such as lines, arcs, text, and dimensions

Visual Fidelity Testing for visual fidelity –Using a widely available test file -Budweiser.dwg –Used for testing the ability of software products to read DWG files –“Pass” criteria is simply that the right and left blocks in each column must be identical upon opening in the CAD application that is being tested –Bentley MicroStation V8 failed 7 of the 18 tests 1 of the failed tests

Performance –For small files (under 1Mb) –AutoCAD 2002 sample file containing common 2D entities. Initial OpenTime AutoCAD seconds MicroStation V811 seconds - 3x slower - –For larger files –12Mb DWG containing lines, arcs, polylines, and text representing city property lines Initial OpenTime AutoCAD seconds MicroStation V852 seconds - 7x slower - Comparing drawing file open times

Model-Based Design Information The display fidelity of model-based design information is critical for users who need to exchange drawings Inaccurate proxy graphics support in MicroStation V8, makes certain drawing data created by customers using Autodesk applications unusable in MicroStation V8 This example shows that with V8 many objects and details are missing such as furniture, windows, landscaping, room tags and 2D objects Viewed in AutoCAD 2002 Viewed in MicroStation V8

Precision For Shared Data Comparing DXF export of a sample file –Sample drawing exported to an AutoCAD 2000 DXF format file using AutoCAD 2002 and MicroStation V8 –Both exports were performed using the default DXF settings V8 issues: Rounding of numerical values Data transfer to other sections of the file Missing information Comparison of the two DXF files

File “Save As” Sizes Comparing size of files with no edited changes –Collection of drawings opened in MicroStation V8, saved as DGN and then “saved” as DWG. All sizes in MB AutoCAD DWGMicroStation V8 DWG % % % % % % % File SizeFiles Size DeltaFile Size

Key Questions to Ask What about obvious visual or plotted differences, are you sure you found them all? What are your support costs when data is missing or corrupt? How identical are two DWG files that look similar when viewed or plotted but are different in size? What issues do you encounter with incorrect data? Your design data is your intellectual property, your competitive advantage, your company’s value-- are you willing to risk it?

Conclusions Bentley’s public claim of “seamless DWG” is relative Bentley, like many other companies, provides basic support for common geometry − lines, arcs and circles –Even commonly used design entities, such as SHX fonts, text styles, linetypes, geometric tolerances and dimension display cause problems –Bentley’s V8 does not provide any support for editing custom objects created by Autodesk applications such as Autodesk ® Architectural Desktop Data integrity and visual DWG fidelity problems do exist in MicroStation V8 Because MicroStation V8 is not completely DWG compatible, the question becomes “what percent of uncertainty in drawing fidelity are you willing to risk?”