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At the start of a round of testing (new rounds start every 6 months), data specifications correlating to specific functionalities (so-called Recommended Practices) and instructions the current testing scope (so-called Test Suites) are provided for creating one or more Computer Aided Design (CAD) or Computer Aided Engineering (CAE) models. These instructions/specifications are generic enough in nature so that the model can be created in any CAD or CAE system. For selection of the models, we try to balance the time it takes to create the models vs. the entity coverage it will provide. A conference call is held among all participants to ensure that there are no misunderstandings with regard to the instructions/specifications or procedures.

Each participant creates the CAD / CAE model and translates it into STEP Part 21 or STEP XML file format. The STEP file is checked to ensure that it is syntactically, structurally, and semantically, correct. If the file meets these criteria, it is "vaulted", and an e-mail notification is sent out to the rest of the participants telling them the file has been approved for post-processing.  

The other CAx-IF participants download the STEP file and translate it into their native system. They then run various diagnostics on it depending on the type of functionality being tested, to further assess the semantic validity and quality of the information exchanged. Some of the statistics gathered are: 

On the CAD domain:

  • Total Volume
  • Total trimmed surface area
  • Coordinates for the center of gravity or centroid
  • Validation property values
  • Model presentation characteristics
  • Product Manufacturing Information (PMI) data

On the CAE domain:

  • Number of nodes
  • Cumulated length, surface or volume for each element type
  • Total mass and position of the Center of Gravity
  • Number of loadcases
  • Resultant of applied loads and resultant moment of applied loads
  • Maximum displacement, strain or stress value

Once the participant has analyzed the imported model, they log on to the member area of the CAx-IF web-site and enter the statistics into the CAx-IF Evaluation, Statistics And Results (CAESAR) system.


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At the end of the round of testing, a meeting is held of all participants where the results and issues are discussed. Sometimes, if an ambiguous part of the standard is encountered, agreements are reached on how to interpret it and documented in the respective Recommended Practices.

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