DRAFT 3 GEANT4 and CAD systems_

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DRAFT 3 GEANT4 and CAD systems_ Powered By Docstoc
					      ESA Spacecraft Radiation Shielding Analysis Software
                    Contract 12115/96/NL/JG - Work order n° 3, Phase 1

              ESA Technology Research Programme

           Space Environment and Effects Major Axis

                             GEANT4 and CAD systems

                Reference: UoS-rep-02

                Version: 1.0 DRAFT

                Date: 28 Nov 98

                Prepared by: R. Gurriaran
                Checked by: F. Lei

                Approved by:

Record of Changes:
Issue       Date                  Detail of changes
0.a         1st April 1998        First issue to reviewers
0.b         3 September 98        Comments of reviewers, extension of information on STEP
                                  compliant CAD systems.
0.c         4 September 98        Comments of P. Truscott
1.0         28 Nov 98             Second issue to reviewers

                                                                 UoS-rep-02, Page 1 of 14
1 Introduction
The aim of this document is to serve as partial output of workpackage 4.1.
In the first part of this document, the STEP standard is briefly described. In a second part, the possibilities of importing
geometries to GEANT4 are reviewed. The precise STEP compliance required for geometrical information exchange is
isolated and the actual status of the GEANT4 step interface is presented. The third part of this document is a report on
the investigation of the STEP compliance of several CAD systems. Finally, strategies for the implementation of a CAD
front end tool for GEANT4 are presented.

2 ISO 10303 (STEP)
STEP (Standard for the Exchange of Product Model Data), officially the ISO standard 10303, Product Data
Representation and Exchange, is described in the official document [1]:
"ISO 10303 is a series of International Standards for the computer-interpretable representation and exchange of product
data. The objective is to provide a neutral mechanism capable of describing product data throughout the life cycle of a
product, independent from any particular system. The nature of this description makes it suitable not only for neutral
file exchange, but also a basis for implementing and sharing product databases and archiving."

Hence, STEP is more than a neutral data format as it also contains the tools to develop new formats. It includes an
object-flavoured data specification language, EXPRESS, to describe the representation of data. STEP also defines
implementation methods and offers different resources, e.g. geometrical and topological representation.

ISO 10303 is divided into eight series of Parts. Each series has a unique function in this International Standard:

   Overview and fundamental principles: defines the principles of STEP.

   Description methods: the EXPRESS data modelling language that represents product information.

   Integrated generic resource: contains the definitions of representation of product information that are common
    for different applications protocols.

   Application protocols: contains the definition of representation of product information that is specific to a
    particular area.

   Conformance testing methodology and framework..

   Abstract test suites: abstract test cases for an application protocol to support the conformance requirements.

   Implementation methods: contain the definitions of the physical representation of product information

Each series may have one or more Part, as it is shown in table 1.

The data exchange is implemented through the Application Protocols (AP). An AP defines how to use STEP entities to
represent data within a specific industry. They are created by industry experts who define their scope and specify what
data is used in the industry (eg. STEP-TAS-012-AP, defined in part by ESA for the field of Thermal Analysis for Space
Applications [2]). Once defined, APs may be accepted as international standards. The status of the different APs
could be found in [3].

Note that "STEP compliant" in the GEANT4 project refers to the AP-203 "Configuration controlled 3D designs of
mechanical parts and assemblies". This Application Protocol contains information on geometry, topology and
configuration management data. For details on the scope and geometry representations implemented, see appendix 1.
From the CAD point of view, STEP compliance refers to AP-203, sometimes to AP-214. At this date, the first is an
accepted international standard, the second is still in a draft form.

                                                                                            UoS-rep-02, Page 2 of 14
      Overview and fundamental principles

      Description methods
            Part 11: The EXPRESS language reference manual
            Part 12: The EXPRESS-I language reference manual

      Integrated generic resources
            Part 41: Fundamentals of product description and support
            Part 42: Geometric and topological representation
            Part 43: Representation structures
            Part 44: Product structure configuration
            Part 45: Materials
            Part 46: Visual presentation
            Part 47: Shape variation tolerances
            Part 48: Form features
            Part 49: Process structure and properties

      Integrated application resources
            Part 101: Draughting
            Part 103: Electrical Connectivity and Hierarchical Product Structure (ECHPS)
            Part 104: Finite element analysis
            Part 105: Kinematics

      Application protocols
            Part 201: Explicit draughting
            Part 202: Associative draughting
            Part 203: Configuration controlled 3D designs of mechanical parts and assemblies
            Part 204: Mechanical design using boundary representation
            Part 205: Mechanical design using surface representation
            Part 206: Mechanical design using wireframe representation
            Part 207: Sheet metal die planning and design
            Part 208: Life cycle product change process
            Part 209: Composite and metallic structural analysis and related design
            Part 210: Electronic printed circuit assembly: Design and manufacture
            Part 211: Electronic printed circuit assembly: Test, integrated diagnostics and
            Part 212: Electrotechnical plants
            Part 213: Numerical control process plans for machined parts
            Part 214: Core data for automotive mechanical design processes

      Conformance testing methodology and framework
           Part 31: General concepts
           Part 32: Requirements on testing laboratories and clients

      Abstract test suites
            Part 1207: Abstract test suite for sheet metal die planning and design

      Implementation methods
           Part 21: Clear text encoding of the exchange structure
           Part 22: Standard data access interface
           Part 24: Standard data access interface - C language late binding

Table 1. ISO 10303 (STEP). The Application Protocol 203 (AP-203) is implemented in GEANT4. Modern CAD
systems usually implement AP-203, sometimes AP-214. Note that not all the parts have yet been accepted as
international standards (eg. AP203 is an ISO standard, AP214 is in the drafting process).

                                                                                     UoS-rep-02, Page 3 of 14

3.1 GEANT4 Geometry Editor (GGE)
GGE [4] [10] is a visual tool intended to create relatively simple geometries (materials, solids, logical volumes,
arrangements of physical volumes) without in-depth knowledge of the relevant GEANT4 C++ classes. It consists of
two editors (materials and volumes) which are interrelated upon user's request:. The output is C++ code with the
complete description of a detector, including the definition of atoms, materials, solids, colour attributes, logical volumes
and physical volumes with rotations and translations, as well as makefiles necessaries to compile with the GEANT4
toolkit. Note that it is a standalone code, running under Java or Tcl/Tk.

In a brief summary, GGE provides the user with
          1) material editor
          2) all CSG solids and two BREPS (pcone and pgon see [5])
          3) visualisation attributes
          4) rotation of solids with respect to the frame or body
          5) single positioned copy of a volume with rotation and translation
          6) many copies (translational or axially symmetric arrangement)
          7) slicing or replica in XYZ, phi, or radius direction
          8) parametrised volumes (yet to be completed - version beta03)
          9) automatic creation of C++ source file to define the geometry.
          10) a suite of necessary files and makefile to compile with GEANT4 toolkit and visualise with OpenGL,
              DAWN or VRML.
          11) persistent file to save the geometry and materials

However, it does not handle the STEP standard.

3.2 Import of GEANT 3 designs
The user requirements of GEANT4 [6] specifies that the code shall be able to use GEANT3 geometry definitions. This
is achieved through two approaches:
 Generation of C++ code directly, which can then be compiled into a GEANT4 program.
 Generation of a language-neutral 'call list' file, an ASCII file giving for each GEANT3 call a full specification of the
    call. C++ routines are provided to interpret this file in a GEANT4 program and build the geometry.
These methods of generating the geometry definitions is presented here for completeness purposes only, as the
interfacing of GEANT3 with CAD tools has already been investigated [7] and found impractical. The solution CAD-
>GEANT3->GEANT4 is even less practical.

3.3 STEP
In GEANT4, an important consideration in the design was the need to exchange geometrical information with Computer
Aided Design (CAD) systems [6]. This interface is achieved using the ISO `Standard for the Exchange of Product
Model Data' (STEP).

The solid modeler used in GEANT4 can describe all the types of solids defined by the STEP standard, and in particular
it can read a detector model from a file written according to the STEP application protocol 203 (AP-203). Detector
models can thus be created or refined using CAD tools. This allows exploitation of the various capabilities of these
tools and the use of the detailed engineering design of a detector for its simulation.

The status of this interface can be summarised as (by November 30 th) [16] :

The STEP Reader, assuring the low level functionalities of the STEP translation, is based on a tool developed by the
american institute of standards (NIST [11]) and made freely available [12].

STEP interface is a new module that reads the Step-file information from the STEP reader module and creates the
respective solids. Today it can process a STEP file containing one solid or an assembly of several solids. An area of
remaining work concerns assemblies that contain other assemblies, which will be implemented shortly.

The solids contained in STEP file are created as instances of Advanced BREP Solids (in Geant4 the class
G4BREPSolid). Each BREPSolid is composed of surfaces, which correspond to the solid specified in the STEP file.
Currently most surfaces can be created. However test coverage of spherical and toroidal surfaces has not been
achieved. Furthermore another complex surface (BSplinecurveWithKnot) cannot currently be created (this is relevant
as spherical surfaces created on CAD systems are saved in STEP files in this form).

                                                                                            UoS-rep-02, Page 4 of 14
Once an Advanced BREP Solid or G4BREPSolid is created, it is utilised by the Geant4 geometry. In doing this the key
methods Inside, DistanceToIn and DistanceToOut are messaged. Testing of these functions has been made and is
continuing. The Inside methods obtains correct results, but the GEANT4 team are working on further testing and fixing
of the DistanceTo functions.

The geometry created through this procedure is flat, it doesn't contain hierarchical information as opposed to the
GEANT3 structure (Mother volume - daughter volumes ...). This geometry structure is not heavily penalised in tracking
performance by the introduction of virtual divisions ("smart voxels" [13]). In order to introduce some sort of
hierarchical information into the GEANT4 geometry, separate STEP files should be read-in, each containing geometry
information with no hierarchy.

The volumes hence instantiated could then be associated with materials properties. It is interesting to note that this is
done in a single line of code (example code from the GEANT4 distribution):

G4LogicalVolume* lv = new G4LogicalVolume(ps->GetSolid(), Lead , "STEPlog");
the "Lead" properties being previously defined.

The main difficulty identified in this study is the association of the STEP file volumes with the correct material
properties, the STEP file containing only geometrical information. Some solutions to this issue will be discussed in
chapter 5.

Note that the export geometries from GEANT4 to STEP capabilities will not be available with the first release of

4 STEP compliant CAD systems

4.1 CAD systems
As it was previously explained, a CAD system which may be interfaced with GEANT4 has to be STEP AP-203
compliant. An initial list of compliant packages was found on the web pages of PDES [15] and on the CERN CAD web
pages [18]. The WWW was searched to find more information on these packages, table 2 lists those for which the
search was positive.
CAD system         STEP compliance Hardware               Price                Contact
ProEngineer        YES                   UNIX Windows        ac : £ 1,500 per J. Turner Parametric
(Parametric)                             NT, 95                           year 01252 817225
Euclid             YES (Euclid 3 + UNIX                           £ 3,000      P. Moorcraft
(Matra             translator)           Windows NT, 95
Datavision)        New version (Euclid                                         Matra
                   Quantum) in beta                                            01203 693939
Catia              YES                   Sun Solaris            £ 20,000       IBM direct
(IBM - Dassault)                         SiliconGraphics                       0990 440055
MicroStation       YES ?                 UNIX                     £ 5,190      D. Prince
(Bentley)                                Windows NT, 95        ac : £ 200      meta4 systems
                                         Mac OS                                0161 877 7221
AutoCAD R14 YES (release 14.01) UNIX                              £ 4,650      CAD DETC
(AutoDesk)                               Windows NT, 95        ac : £ 295      0113 245 2288
TriSpectives       YES                   Windows NT, 95             £ 650      J. Wright
(3D/EYE)                                                       ac : £ 230      01747 822 404
I-deas             YES                   Windows NT          ac : £ 4,000
(SDRC)                                   UNIX                                  m
Table 2. CAD systems which are STEP AP203 compliant. (ac : academic price). Appendix 2 gives details of the
AP203 compliance.
Three were not listed in table 2 : they were eliminated from further research as they were identified as unsuitable for
this project.
          CV/CADDS5         :        merged with ProEngineer
          Applicon/BRAVO :           tool-machining software

                                                                                             UoS-rep-02, Page 5 of 14
          Msc/Aries        :        mechanical simulation tool.

The vendors were contacted and further information about pricing policy and STEP compliance was requested. During
this step of the investigation, ProEngineer and I-deas representatives visited Southampton University. Matra proposed a
visit to their headquarters.
It has to be noted that neither AutoCAD representatives (CADDETC) nor Autodesk Ltd UK, have given any answer,
even after being requested a total of 9 times, by Fax, phone, and letter. Hence the information in AutoCAD comes from
their web pages solely.

The latest status (August 98) and more detail of the STEP compliance can be found in Appendix 2.

Comments on Table 2: Price information
Some of these packages are extremely modular, and prices depend on the modules chosen. However the prices stated
correspond to the system necessary for the interfacing with GEANT4, as it was understood by the vendors (table 3).

        Object Manager : 4,000 £
        Space Analysis : 4,000 £
        STEP translator : 9,000 £
        ...
        Complete 3D modelling : 20,000 £
AutoCAD : price includes solid modelling package.
ProEngineer and Ideas: price includes STEP translator.
TriSpectives : Standalone package.
Table 3. Examples of the modularity in features and pricing of modern CAD software

Comments on Table 2: STEP compliance
It is interesting to note that STEP compliance is rapidly evolving, from the first draft of this document to now (end
August 98):
 AutoCAD step translator has evolved from beta release to full release
 Bentley MicroStation STEP translator may have evolved beyond beta release. The vendor has not answered letter
    and phone request on the subject. However the web pages of the "Beta Release Translator" has disappeared, and the
    MicroStation home page indicates STEP compliance.
 Matra Datavision has 2 versions of their product:
          1 - Euclid 3 is available with a third party STEP translator. It should be noted that the CERN CAD web pages
     cited this configuration. However Euclid 3 is an old product and shall soon be replaced by the new version.
          2 - Euclid QUANTUM is Matra's new generation of CAD system. The compliance to the STEP standard will
     be excellent as the system is based on a STEP compliant kernel. Its status in May 98 was "beta testing for at least 2

4.2 Libraries
In table 4 is shown an alternative solution for a CAD front end to GEANT4: to build customised software using the
libraries sold by Matra (cas.cade). This library contains all the commands required to build a 3D geometrical modeller
directly using the STEP format. It was used for the new version of Euclid (Euclid Quantum in beta testing). The use of
this library linked to the GEANT4 library will permit the creation of a standalone code uniting model generation and
Monte Carlo simulation. The price and the intensive coding required place this elegant solution beyond the scope of
this work.
SDRC has such library too (OPEN I-deas), however it does not contain the code for the STEP format.

Library                   STEP compliance AP- Hardware                         Price
cas.cade                  YES                 UNIX Windows                     10,000 £+       copyright
Matra Datavision                                                               policy
OPEN I-deas                NO.       Third     party                           20,000 £
(SDRC)                     translator required
Table 4. libraries giving access to 3D geometrical modeller commands.

                                                                                           UoS-rep-02, Page 6 of 14
4.3 Share of Market and STEP files.

In the second stage of this investigation, it was decided to request a STEP file from the vendors created with their
product and also information on their share of market in the European aerospace industry. Table 5 summarises the
                                               STEP file                      Share market
ProEngineer                                       Yes                           No Answer
Euclid                                     Not Available yet                    No Answer
I-deas                                            Yes                  Yes (see appended document)
TriSpectives                                      Yes                           No Answer
Bentley MicroStation                          No Answer                         No Answer
AutoCAD                                       No Answer                         No Answer
Table 5. Answers to the request of a STEP file and share of market information.

With the exception of I-deas, none of the vendors have answered the share market request (appendix 3).

ProEngineer, TriSpectives and I-deas fulfilled the STEP file request. Matra explained that they could not reply as their
product was not available yet.
Note that AutoCAD and Bentley did not answer at all. When requested by phone (mid-July) Bentley replied that the
technical group was taking care of the request.

4.4 Testing of TriSpectives 3D/EYE.

After the decision between DERA and University of Southampton a copy of TriSpectives was bought for further hands-
on testing. The package was delivered at the beginning of August, and installed in the 3 week of August.

4.4.1 Description of the package
The "TriSpectives Technical ver.2" package was installed in a 400 MHz Windows 98 machine. Installation time was
less than 10 minutes and went smoothly.
The usage of the package is extremely simple: the design can be done by drag-and-drop of pre-existing entities (sphere,
box, cylinders, holes…...) or by the use of tools permitting the creation of Brep objects. Any design can be entered into
the catalogue of pre-existing entities to simplify their later use.
The dimensions and placement of objects can be done in a visual mode (understandably not very accurate). It can also
be done in a very accurate mode using existing tools that however require in depth reading of the manuals.

The package contains an "interference checking tool" which could be essential for the design of complex systems. The
test of this feature showed an extremely basic design: the user has to select two volumes, the answer being a yes/no
there is a clash. If there are hundreds of elements, this feature is simply impossible to use.

4.4.2 STEP testing
Designs and part of designs were easily exported and re-imported to and from the STEP standard. However it was
found that the re-imported design was transformed in a single volume, whatever the number of elements it was
previously composed. Any attempt to manipulate the re-imported design (eg. drill a hole) crashed the computer.

ProEngineer and I-deas STEP files (all containing a single-volume) were imported. A problem appeared with the I-deas
file : the model was imported but inconsistent lines appeared. No conclusion could be made on the origin of this
problem. Tests to import more complex (33 and 300 volumes) STEP files from Pro-Engineer failed, provoking the
crash of the code.

Finally, the study of the TriSpectives STEP file showed no way to uniquely identify each of the volumes. Comparison
with other CADs STEP files permitted to point out the absence of a delimiter containing the name of the volume.
In conclusion, the STEP feature of TriSpectives seems to be designed for the import/export of a single complex shape.
Hence it is not suitable for the objectives of this project.

4.4.3 Obsolescence of the package
Shortly after it was sold to the University, the 3D/EYE package was declared obsolete by TriSpectives. No more
packages will be sold after the 31 August. The vendor did not bring this information to our attention, as he was

informed just after shipping the software to us (end July). TriSpectives will be replaced by IronCAD. This new

                                                                                             UoS-rep-02, Page 7 of 14
software is described by the vendor to be similar to the old one, the main differences being the drawing and assemblies
capabilities, STEP translation has also been improved.

                                 TriSpectives                    IronCAD
Full price                       £ 650                           £ 2400 (US$ 3995)
Academic price                   £ 200                           None applicable
The upgrade price from TriSpectives to IronCAD is $2995. After explaining our position an upgrade was proposed for

4.4.5 Conclusions on TriSpectives 3D/EYE
The software is very easy to use. However, it was found to be very limited, not only for the interference checking but
also the most important part in our application: the STEP compliance. This and its obsolescence make that it is not a
possible solution. IronCAD may be an alternative in functionality but there is an uncertainty about the cost
effectiveness of this solution. The off-hand way of dealing with the end-users by the 3D/EYE company should also be
taken into account.

4.5 Conclusion on STEP compliance

During this study we found that the CAD market is rapidly adapting to the STEP compliance actually demanded by
industry (see commercial release dates in appendix 2). Its fluidity was also shown by the obsolescence of the product
we chose for testing.

The AP203 format is a well-defined industrial standard. Any CAD system claiming to be compliant is -in theory-
capable of exporting geometries to GEANT4. However, the problems we found using the TriSpectives package show
that this is not necessarily true. They seem to be created by a limited implementation of the STEP standard in the
TriSpectives product.

A positive result of this experience is that it has permitted to point out an important feature: Even if the geometry in the
STEP file is correct, it could not be used if there is no identification tag to associate the volumes to a materials
properties database. The natural way is to include the name of the volumes in the STEP file. This issue was
investigated, with the following results:

 I-deas representative assured us that this is a standard feature of this package.
 Pro-Engineer STEP files were found to name the different volumes. In fact, the GEANT4 distribution contains two
  STEP files from Pro-Engineer with these name tags filled.
 IronCAD answered sending a STEP file. However no definite answer could be raised from its study.
 Bentley MicroStation and AutoCAD were contacted on this issue as well. No answer has been forwarded.

5 Conclusion

The CAD front end for a geometry/material definition is technically feasible as long as the GEANT4 toolkit reaches its
maturity with respect to the AP203 standard. For the moment, tests with beta versions have not been very successful.

The most general approach for this front end is to run the CAD tool, and in parallel a materials editor. The association
of materials and volumes would then be done inside the Monte-Carlo code. Different options were identified for this
association :
1. Specify the volumes by name within the CAD tool, and use these names in the material definition process. It may be
   reasonable to make it a requirement on the CAD tool to have the capability of naming volumes in the STEP file.
   STEP files with volumes not named could always be imported and names added in such a CAD tool. This option is
   the more general, and is in the logical trend of the STEP interface.

2. Define the geometry with a CAD tool which does not allow volumes to be named, then by using GEANT4 routines,
   read-in the STEP file and allow the user to specify the names of the volumes. A modified STEP file would then be
   created in conjunction with a materials file which defines the materials by volume name. One difficulty is that the
   STEP read-out function within GEANT4 will not be ready for the first first release of the code. A further drawback
   is that the process will have to be repeated each time the geometry is edited using the CAD tool. There is the
   possibility of using commercial libraries (ie. ST-Developer from Steptools, $ 12,125 for a UNIX licence, $6,500 for

                                                                                            UoS-rep-02, Page 8 of 14
   a Windows NT licence). This option does not seem satisfactory as it is the equivalent of re-writing what has already
   been done for GEANT4, then add a few functionalities.

3. A somewhat less elegant but pragmatic solution is to associate one or more Cartesian co-ordinates with each
   material, then use these to determine the volume-material relationship as the STEP and materials files are read into
   GEANT4. The key difficulty is that the user would have to be careful to update his materials file whenever the
   volumes are moved, as well as when the number of volumes is changed.

The first option is in our opinion the best:
- it is within the scope of the STEP standard.
- the front end developed will be more user friendly than the 2 other options
- the front end would be easier to develop

The general idea when starting this investigation was that any STEP compliant tool could be used as part of the front
end. The TriSpectives experience has proved that it is not the case. If we divide the CAD systems in high middle and
low price (based on the academic offer):

High :
- CATIA, was not further investigated due to its high price..

Middle :
- ProEngineer and I-deas seem to have the functionalities required.
- IronCAD : no definite answer could be raised concerning the STEP names problem.
- Euclid is not released yet.

Low :
-MicroStation and AutoCAD could not be recommended for the moment, as they have not been tested/investigated, due
to the non co-operation of the vendors.

All these CAD systems have the potentialities to be used as a CAD front end tool. After our study and the information
odbtained so far, it seems that ProEngineer and Ideas are the two best choices.


[1] ISO IS 10303-1. Industrial automation systems and integration - Product data representation and exchange - Part 1:
Overview and Fundamental Principles.
[2] STEP Application Protocol Thermal Analysis for Space - Project Development of Thermal Neutral Formats, ESA
contract No 10596/NL/FG
[3] STEP on a page :
[4] More information could be found in geant4beta/environments/Momo/GGEmake/README, part of the GEANT4
[5] "GEANT 3 Detector Description and Simulation Tool" - CERN Program Library Long Writeup W5013, GEOM050
[6] GEANT4 OO Toolkit for Particle Detector Simulation. User Requirements Document. Version 6. 19 Nov. 98.
[7] GEANT3 and CAD systems. UoS-rep-01
[9] Concept of Operations for Application Protocol 203 - PDES, Inc. ME003.02.01 August, 1993
[13] RD44 collaboration, GEANT4: An object-Oriented Toolkit for simulation in HEP, June 1997. CERN/LHCC/97-
40 ; LCB Status Report/RD44.
[16] John Apostolakis, private communication.
[17] Steptools :
[18] CERN CAD :   
                                   Appendix 1
         AP203 - Configuration Controlled 3D Design of Parts & Assemblies
                                                                                         UoS-rep-02, Page 9 of 14
References [8] and [9].

Scope of AP203
 Advanced Boundary Representation (& other 3D forms), AP203 allows for a number of different levels of shape or
   geometry definition to be exchanged.
 Part Identification (part numbers and versions)
 Bill of Materials (product structure, positional data)
 End Item Identification (saleable items)
 Effectivity (use of parts in a saleable product)
 Design Activity and Change Control
 Authorisation (approvals, person, organisation)
 Design Information (material, process and surface finish specs)
 Source Control (suppliers and supplied parts)

The above applied to the PRODUCT (not the drawing or the scheme or a CADCAM model .......)

Process scope
In Scope
 Design and exchange of the design data to other life cycle phases
 Design : conceptual, preliminary, main and detailed
 Design change and all data related to that function
 Data for tracking the design's release, including approval and the designation of the contract under which the design
    was developed.

Out of Scope
 Analysis and test information
 Constructive solid geometry (CSG) or non manifold representations.

                                                                                       UoS-rep-02, Page 10 of 14
Reference : Concept of Operations for Application Protocol 203 - PDES, Inc. ME003.02.01 August, 1993

Types of Geometry Representation

AP203 contains a number of conformance classes. These consist of a base configuration level (class 1) and then other
classes with differing types of 3D geometry representation.

 CLASS1 : Configuration management (information without shape)

 CLASS2: CLASS1 + surface and wireframe without topology

 CLASS3 : CLASS1 + wireframe with topology

 CLASS4 : CLASS1 + manifold surfaces with topology

 CLASS5 : CLASS1 + faceted boundary representation

 CLASS6 : CLASS1 + Advanced Boundary Representation

                                            Appendix 2.
                                 STEP compliance status in August 98.
extracted from PDES, Inc [14].

          Vendor             Commercial      1          2           3       4        5         6
                             Release date
PTC/           ProEngineer       Q1/97       P          X                   X                 X
SDRC (Ideas) V6.0                Q1/98       P          X                   X                 X
AutoCAD (R14.01)                 Q3/98       P          X                   X                 X
Dassault/CATIA (V4.2.0)          Q3/98       P          X           P       X        X        X
Bentley/MicroStation             Q4/98                  X           X       X        X        X
Bentley/MicroStation J           Q1/99                  X           X       X        X        X
Matra/Euclid                     Q1/99

No information was found in PDES Inc web pages about TriSpectives or IronCAD products.

Key to AP203 Conformance Classes :
1. Configuration Management
2. Surface and Wireframe
3. Wireframe with Topology
4. Manifold Surfaces with Topology
5. Facetted Boundary Representation
6. Advanced Boundary Representation

                                                                                     UoS-rep-02, Page 11 of 14
Updates provided by vendors
- An "X" denotes full support
- A "P" denotes partial support

                                              Appendix 3
                                  Answer of the Share Market request

1 - Answer of IronCAD representatives :
(extract of their e-mail answer)

Date: Tue, 06 Oct 1998 11:00:49 -0500
From: Karl Ellis <>
Subject: RE: IronCAD!

I'm not sure if I can separate how many
engineers in Europe that have a seat of IronCAD are in aerospace, but I
know that Boeing has a couple of seats of IronCAD in the US. With nearly
a Thousand seats of IronCAD sold in 3 months we have taken the industry
record for most seats sold from the initial launch.

-Karl Ellis

2 - Documents from Ideas representative

                                                                           UoS-rep-02, Page 12 of 14

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