# Presentation: 201924

## The NASA STEP Testbed Pan Galactic Engineering Framework (PGEF)Implementing a STEP-basedIntelligent Master Model forSystems Engineeringand the “Model-Based Enterprise”

- Stephen C. Waterbury
- NASA / Goddard Space Flight Center

**Notes:**
NASA’s Intelligent Synthesis Environment (ISE) initiative and its Collaborative Engineering Environment (CEE) will require sophisticated capabilities for the sharing and configuration management of engineering models.  Engineers using these advanced environments will have state-of-the-art tools for Computer-Aided Design, Analysis, Simulation, Systems Engineering, Software Engineering, and other engineering disciplines.  Each of these discipline’s tools focuses on a view that is in some ways unique and separate from other engineering disciplines, and yet the design of a particular item often requires a collaboration between two or more disciplines -- for example, a printed circuit assembly must be designed and analyzed from the mechanical as well as the electrical point of view in order to meet all system requirements.  
The engineering models on which the tools of different disciplines operate are unique in important ways, but if tools from different disciplines are brought to bear on a single product, it is important for data integrity that all tools work to a common underlying structure.  This common underlying structure is contained in the STEP standard (ISO 10303), “STandard for the Exchange of Product model data”.
This presentation will discuss how STEP can be used to provide a common structure to which all engineering discipline models refer, so that data integrity and configuration management are maintained.

## PGEF Acronyms and Definitions

**API **............. Application Programming Interface
**CAD **........... Computer-Aided Design
**CAE **........... Computer-Aided Engineering (typically, analysis)
**Express **...... an information modeling language
**Express-X **... maps between & creates views of Express models
**PDM **........... Product Data Management
**PGEF****TM**** **....... Pan Galactic Engineering Framework
**PGPDM **...... Pan Galactic PDM (a PGEF *application*)
**SE **................ Systems Engineering
**STEP **.......... Standard for the Exchange of Product Model Data                        (ISO 10303)

## The NASA STEP Testbed

**Purpose:  Leverage STEP technology to support collaborative engineering in NASA projects**
**Approach:  Implement STEP-based software for Systems Engineering (SE) and Model-Based Enterprise (MBE)**
**Pan Galactic Engineering Framework**** (****PGEF****) software**
**NASA federated STEP-based Systems Engineering Repository**
**Collaborate with and support NASA centers in implementation and deployment**

## Goals of PGEF(Hub or “Server” Functions)

## Goals of PGEF(UI or “Client” Functions)

## Okay, fine, but why Python?!

## Model-Based EnterpriseMaster Model Integration Using STEP

**Model-Based Enterprise****Master Model Integration Using ****STEP**

**Integrated STEP**
**Master Model**

**Express-X**
**Maps**

**Notes:**
This diagram illustrates the concept of “Intelligent PDM”.  The essential ingredients for Intelligent PDM are:  
(1)  a set of discipline-specific information models (the examples shown are the STEP Application Protocols 203 [MCAD], 209 [Finite-Element Analysis], 210 [ECAD], and 232 [Systems Engineering]);
(2)  STEP translators for the discipline tools:  since Intelligent PDM is based on STEP, each tool to participate in this environment must have a STEP import/export capability;
(3)  a Product Master Model, which incorporates the STEP AP’s as subsets and represents each common object once.  For example, the geometry of the product is a subset of the Product Master Model, and is “reflected” in the MCAD, ECAD, and Analysis models, in which it may have different projections (e.g., 2-D or “2.5”-D in an ECAD model) or transformations to lower fidelity.  The Product Master Model could be thought of as a “union” or “superset” of all the discipline models of the product. 
 (4)  mappings between the discipline-specific views of the product (the STEP AP’s) and the Product Master Model.  These mappings are being developed using the EXPRESS-X mapping language, a new part of the STEP standard.
The diagram depicts the discipline tools feeding their models through the STEP AP’s and mappings into the Master Models for Spacecraft X and Instrument Y.  The Intelligent PDM system can then generate, through the reverse mappings, the changed versions of the other discipline models.

## The Product Master Model EvolutionPopulation of Master Model Contents Over the Project Life Cycle

**Notes:**
Another benefit of the Intelligent PDM approach is that it provides continuity of the product’s definition as it evolves through the various phases of its development life cycle.  
Imagine the Product Master Model’s framework as a large set of “shelves” or labeled compartments for the various aspects of a comprehensive product model.  In the early conceptual definition of the product (corresponding to Pre-Phase A studies for a NASA mission), only a few of the shelves or compartments are populated, and that data may not be complete in the early stages.  Still, it is important to propagate that high-level data, containing requirements and mission parameters, to the later phases of development and to allocate it to the various aspects of system design that it defines and constrains.  These allocation relationships are supported in the Product Master Model, and can be viewed by the systems engineer at any point by extracting the systems engineering view of the evolving Master Model.
In the early phases, the model may be populated just enough to enable low-fidelity simulations, for example.  Another benefit of the Product Master Model is the capability to identify what additional data is needed in order to generate particular types of analysis or simulation models.  
As the Product Master Model becomes fully populated, more detailed views and simulation models can be generated, until finally the design model can be used to generate detailed drawings and fabrication models.

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## Slide 10

## Use Cases

## Use Cases

## Use Cases

## Use Cases