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Legacy data migration for the MBE environment

Posted by Andy Chinn on January 5, 2017
Andy Chinn

The ongoing revolution for a lot of today’s engineering enterprises is the implementation of 3D Model Based Design (MBD), using applications such as CATIA 3D Master, where all Product Manufacturing Information (PMI) such as functional tolerances, dimensions and annotations reside in the master 3D CAD model rather than in linked associative 2D drawings.

If you are implementing MBD within your company, then new 3D CAD models will be created with 3D PMI data included from the beginning. But what about your existing CAD model data? You have a significant investment in existing product designs and standard parts that consist of 3D CAD models with linked 2D drawings that you want to be able to re-use in the MBD environment.

The re-use of existing data is not usually top of the agenda when customers plan their MBD implementations. However, effective legacy data re-use is central to facilitating a faster and more widespread adoption of MBD and will help provide an earlier realization of the MBD process benefits.

The first option usually considered for data re-use is the manual remodelling of legacy parts in the MBD environment with 3D PMI included. This is closely followed by the option of an engineer interpreting the 2D PMI in the original drawings, extracting the data, and then adding the required 3D PMI entities to the original 3D model.

However, both of these options are expensive, extremely labor intensive and susceptible to human error. The effort required is such that one customer was considering the expense of employing a team of contractors specifically to deal with legacy model recreation for their new MBD environment. 

2dpmi1.pngFigure 1: The requirement to migrate 2D & 3D legacy data

As with any manual remastering process, there is also the serious risk of design deviation and unexpected changes being introduced as a result of human error when interpreting data in the source 3D part and 2D drawing and manually transferring the design intent to the MBD part.

Clearly a more effective solution is needed to enable companies to migrate their existing CAD models to the MBD environment and maximize data re-use. A requirement exists for an automated solution that can extract the necessary manufacturing information from a 2D drawing and add it to the 3D part – enter DrawtoPMI, an innovative solution from ITI.

DrawtoPMI supports the migration of legacy CAD data for use in the MBD environment. DrawtoPMI takes as input a 3D CAD model with its associated 2D drawing file and automatically combines them into a single 3D part file containing all of the 3D PMI, including views, cross-sections, functional tolerances and annotations, ready for immediate use in the MBD environment.

DrawtoPMI creates Annotation Sets in the MBD model with the 3D PMI data organized into different View Captures, each one equivalent to one of the original 2D drawing sheet views. The MBD user can navigate through the View Captures to review the 3D PMI information as needed.

In the case of CATIA V5, DrawtoPMI uses the CATIA API to interrogate the associative views in the 2D drawing. It extracts the PMI data, intelligently maps PMI entity associativity from the 2D drawing geometry to the appropriate 3D part geometry, and automatically creates the required FT&A entities in the CATIA V5 3D Master model.

By using the CAD system API to interrogate and extract the 2D PMI data, and then to create the 3D PMI entities in an automated programmatic solution, users have the confidence of knowing that any issues of accuracy and design intent deviation due to human interpretation errors have been eliminated.

2dpmi2.pngFigure 2: DrawtoPMI automatic legacy data migration for CATIA 3D Master

DrawtoPMI will also transfer non-associative dimensions in order to support the need for everything in the 2D environment moving to the MBD model. The ability to create non-associative 3D PMI entities also allows DrawtoPMI to handle any incompatibility issues between creating dimensions in a drawing, versus creating the same dimension as a 3D PMI entity.

If any non-associative 3D PMI entities are created in the resulting MBD model the user can decide whether to complete or reattach dimensions to the 3D geometry, using the DrawtoPMI Completion Wizard to guide them.


Figure 3: Non-associative dimensions from the 2D drawing are preserved, and displayed in a darker color to alert the user.

The DrawtoPMI process can take anywhere from a few seconds to a few minutes, depending on the complexity of the source data. By automatically combining legacy 3D parts and 2D drawing files, DrawtoPMI can save months of manual work and provides a compelling return on investment. One leading automotive manufacturer was faced with the task of migrating a complex power train component that included 6 drawing sheets, 58 associative views and over 1,000 dimensions. The manual effort to recreate the PMI data in the 3D part was estimated to be at least three weeks. DrawtoPMI transferred the PMI data to the MBD model automatically in less an hour, with an additional two hours manual review and completion.

DrawtoPMI is an essential tool for any company implementing a Model Based Design environment. It enables the fast and efficient migration of legacy data and eliminates the need for expensive, error prone manual migration processes. DrawtoPMI will speed up your company’s implementation of Model Based Design, facilitate a faster and more widespread adoption of MBD, and help deliver an earlier realization of the benefits of deploying MBD processes across your organization.


Topics: CAD, Migration, MBE/MBD, PMI