Overview of CAD Geometry Comparison Tools

For decades CAD salesmen have been promising to do away with 2D drawings, and to remove barriers to collaboration. But with passing year, we tend to see more roadblocks to communication and collaboration when that work has to be done between users of different CAD software. It is clear that real interoperability solutions are not going to come from the big CAD vendors.

There are standards in place, like ASME Y14.41-2003 which define methods for sharing PMI – Product Manufacturing Information through the practice called model based definition (MBD). This standard helps a neutral format such as STEP carry much more than just a geometrical representation of a product. It will also include GD&T (geometric dimensioning and tolerancing) connected directly to the 3D model, information on materials and surface finish, among other things.

The use of these standards is being pushed by the aero and auto industries, but they will benefit any enterprise that lives in a multi-CAD world, or needs to share information with users of different CAD software. Several geometry comparison tools on the market can already take advantage of PMI in translated files.

Comparison tools can be used in various ways including finding expected engineering changes between different versions of parts, and secondly for validating accurate geometry and PMI data transfers between CAD software programs.

This article offers a brief summary of some of the CAD comparison tools that are available from companies other than the big CAD vendors (Autodesk, Dassault, PTC, and Siemens PLM).

Kubotek Compare

Kubotek Compare is a $2500 add-on to KeyCreator which I wrote about in more detail in a previous article. It can work as an add-on for KeyCreator or independent from CAD as part of the Kubotek Validation Suite. Compare enables you to compare parts and assemblies, as well as comparing solids, surfaces, wireframe, point cloud, and mesh data. It uses geometry recognition to classify topology (cylinder, planar, torus, etc.) and offer a face count for each type in each of the compared models.

Because KeyCreator has a wide range of import formats, with Compare, you don’t need to get an exported file from the original system, you can just read the file directly. So you could compare a native Pro/Engineer file directly against an ACIS file. Compare also can deal with finding changes to PMI as text based dimensional or meta data.

Kubotek’s report writing also sets it apart with visualizations and quantitative analysis of the differences. Plus, the idea of having a comparison tool connected to a direct editor is compelling, for when you need to make changes to the imported data.

CapVidia

CapVidia has four products to help you work in your multi-CAD world: 3DTransVidia ($4850+), CompareVidia ($2850), and their respective SolidWorks add-ins, FormatWorks ($3500 – $6000) and CompareWorks ($1850).

CompareVidia /CompareWorks  use a parallel translation process to validate the results of imports into SolidWorks. So for example, it will read a Pro/E file directly, and compare it to the translated file. The result is a “go/no go” situation, where it is not telling you where the areas of difference are, just that differences either exist or they do not, followed by a report. The Compare products work on the following formats:

CATIA V4 (.model, .exp / up to 4.2.4), CATIA V5 (.CATPart, .CATProduct / up to R20), CATIA V5 PMI, Unigraphics (.prt / up to 18, NX6.0), Unigraphics PMI, Pro/E (up to Wildfire 4), Pro/E PMI, Inventor (up to 12), Parasolid (up to 20), ACIS, STEP, IGES (5.x – 6.x), VDA-FS, AutoForm (.af, .afm), STL, VRML, 3DTransVidia XML

3DTransVidia / FormatWorks offer streamlined data import tools. Functions include PMI support, automatic and manual repair tools. While these products do not help with comparison or validation directly, they will help you get better quality imported data in the first place.

EnSuite

EnSuite, at $3495 per year, comes from CCE (CADCAM-E), a Michigan based company in business since 1989. Their business is centered on CAD translation, visualization, and product configurators. They are involved in migrating history tree information between various CAD systems. EnSuite is a multiCAD view/markup/measure/compare toolbox which is useful in any sort of shop that receives a variety of data types.

EnSuite can make use of a model points comparison in addition to face-to-face comparisons. It can also compare assemblies, and create BOM data. It will show interference volumes, contact area and clearance between parts in an assembly.

EnSuite also allows multiCAD functionality you may have never considered to use a viewer for. For example, you can insert a SolidWorks part into a Pro/Engineer assembly, position it, and check for interferences.

CADIQ

CADIQ is a product from ITI TranscenData, an Ohio based firm that focuses on product development productivity. In existence for 15 years, they claim CADIQ to be the first validation tool on the market. Along with the comparison tool, they also offer tools such as CADfix – to repair translated data, Proficiency – a feature-based translation tool, and DEXcenter – used by Boeing and Honeywell, is a secure web-based automated data exchange providing multiCAD output to get data to suppliers in the formats they need.

CADIQ is an automated tool that checks models for manufacturability or reuse problems, as well as unplanned changes in the model geometry arising from issues such as translation errors, misunderstood parametric relations, undocumented changes, and unanticipated assembly product structure changes. CADIQ also compares 3D PMI, including GD&T.

CADIQ can also be used in batch mode and use distributed computing. The front end installs as a plugin for Catia V4 & V5, Pro/E, NX, CADDS5, or SolidWorks. This enables the data originator to validate the models being sent out to assure that the translated geometry and PMI is the same as the native geometry. CADIQ can also be used as a component in the DEXcenter, which automates data exchange through a web-based interface. The Support/Specs area of the CADIQ website indicates that a standalone interface is also available for customers who do not have the native system available. Standalone interfaces are available for the above systems as well as JT, STEP, IGES, Parasolid, and ACIS file formats.

Long term data archival is another use of CADIQ. During the translation, CADIQ can embed properties into the STEP file that enable a user of the data to validate that the resulting translated model is geometrically the same as the original data in its native format.

Prices for CADIQ start at around $10k, increasing substantially depending on configuration and implementation details.

Core Technologie 3D_Evolution

Advanced Compare is just one of the tools in the 3D_Evolution suite from the German company Core Technologie. The entire suite is focused on CAD interoperability, and each module is impressive on its own. I found Advanced Compare to be the most visually communicative of all of the comparison products presented in this article. The interface seems to be the best developed, and it presents information in a highly useful manner.

In addition to straight comparison of geometry, Advanced Compare can also perform a thickness analysis to find areas under or over a defined thinness/thickness value. Thin areas can be isolated and use a color scale to indicate values. Sections are as easy to cut as dragging the cursor across a part.

Advanced Compare also compares assembly, including both the individual part geometry and the overall assembly structure. It will also detect any interferences between parts in the assembly. The software also creates an HTML based report file of the results.

AutoVue

AutoVue is owned by Oracle, and is included with some file management software packages like Synergis Adept. AutoVue is primarily a viewer, and can handle many types of 2D or 3D CAD, geometrical, image, and text based documents, as well as allowing markups. It does have a compare utility to show additions in one color, and subtractions in another color. It can also do certain manipulations with 3D CAD data such as exploded views and section views.

Licenses for AutoVue range from about $300 for a single user license of AutoVue to about $1000 for the SolidModel Professional.

WorkNC

WorkNC from the multinational Sescoi sells CNC ($12-30k), CAD ($3900)  and WORKXplore3D viewer software ($1500). The CAD and viewer both contain the geometry compare function. A free version of the WORKXplore3D viewer can be downloaded, but does not contain the comparison software.

In addition to geometry comparison, it also enables comparison of the content of layers within the XDW file. This is intended for two purposes: comparing a new file against an existing file to check for changes to the CAD data and also to check a machined and then scanned part against the original CAD input to make sure the machining was correct.

The Compare Geometry function within WorkNC shows the differences between parts as “Material To Add” and “Material To Remove”, and the order of the Original and Modified part files can be switched. You can adjust the tolerance between surfaces, and selectively deactivate layers.

TurboCAD Drawing Compare

TurboCAD Drawing Compare is a $130 stand-alone application that compares 2D and 3D CAD data as well as PDF, vector and raster image files. After a little investigation, the “3D” appears to mean a wireframe comparison done from a predetermined view. It supports DWG, DXF, SketchUp, TurboCAD, DoubleCAD, PDF, JPG, PNG and BMP.

OverCAD

OverCAD is a CAD software development house specializing in AutoCAD related software. The domain name is registered to a company in China, and is likely a single person writing some utilities. The website has very little information about the company, but they do have four products for sale, ranging from the $30 DWG DXF Converter for AutoCAD to the $280 DWG Compare for AutoCAD. In a bit of Chinese software piracy irony, OverCAD tools are readily downloadable from many sharing sites across the web.

ZWCAD

ZWCAD is a Chinese 2D drafting package that includes a 2D compare utility. ZWCAD is the same company that purchased the former VX product and renamed it ZW3D.

This article was originally written for TenLinks.com, and has appeared on CADdigest.com.