EXPERIMENTAL AND MATHEMATICAL PHYSICS CONSULTANTSPost Office Box 3191 Gaithersburg, MD 20885 USA voice: (301)869-2317Document 2001021701 facsimile: (301)963-39022001 February 17 email: tjordan@empc.com

NOVICE CAD Interface

Summary: The NOVICE code system is used by a number of organizationsfor the analysis of space radiation effects such as total ionizingdose (TID), damage (NIEL, non-ionizing energy loss), SEE (singleevent effects, upsets, latches), and sensor response (noise spikes,coincident/anti-coincident counts.) For system level analysis, theplatform geometry is modeled because it can provide substantialshielding; but the modeling constitutes a large part of theengineering effort. A CAD (computer aided design) interface has beenimplemented in NOVICE to simplify this modeling. The interface isbased on the STEP protocol, ISO 10303, (Standard for the Exchange ofProduct Model Data.) The status of the implementation, andrecommended CAD modeling practices that would simplify the use of CADmodels, are described.

Discussion: The analysis of radiation effects on space platformsrequires modeling the transport of the space radiation environmentthrough various materials to the component being analyzed, usually anelectronic component or a particle sensor.

The dominant space environments are charged particles: trappedelectrons and protons, galactic cosmic rays, and solar particleevents (protons and some heavier ions). For some analyses, neutralparticle modeling is also required for secondary bremsstrahlungphotons and secondary neutrons.

Detailed geometry modeling is often used. The additional materialsusually provide reductions in radiation levels beyond what isestimated for more simple models such as box walls and part covers. Moreover, accurate assessment of the transport may require geometrydetails, particularly for sensors and for predictions of the effectsof secondaries.

Historically, geometry models have been generated by readingblueprints and then transcribing dimensions and shapes intoinformation understood by the transport codes. Typical shapes

include rectangular, cylindrical, conical, and spherical surfaces(the boundaries of objects), and these basic shapes were combined byBoolean logic (intersections and unions) along with materialcompositions/densities to produce the model. The modeling was errorprone and required large expenditures of effort to produce a finalmodel. However, the reduction in radiation levels often obviated theneed for part level and/or box level shields which are even moreexpensive in both implementation and launch costs.

The blueprints that were once generated at a drafting table are nowproduced by computer aided design (CAD) systems. The CAD systemshave progressed from producing simple line drawings with annotations,through solid modeling (similar to the modeling in transport codes),to the current systems where objects are often the same simple shapes(cylinders, cones, ...) but also allow an additional level ofcomplexity where the surfaces of objects are described by a numbersurface patches (thousands for a single object is not unusual) wherethe patches may be simple, such as a plane bounded by a set ofconnected straight lines, to complex, such as a NURBS surface (non-uniform rational B spline surface, basically a spline interpolationusing 3-D control points) bounded by spline curves (a splineinterpolation of a 3-D curve also using 3-D control points.)

While the CAD systems have surpassed the transport codes in modelingcomplexity, they can provide all (or most) of the data required for adetailed transport analysis. Fortunately, the interchange of databetween CAD systems has received a lot of attention. A decade ago,IGES was the standard for exchanging data between systems; this hasbeen replaced by the STEP standard. It is also fortunate that gameplayers on the PC have produced a large demand for high-end graphicscards. As a result, the methods used for fast viewing of geometriesare now available on all personal computers (PCs). The CAD model isfirst reduced to a set of polygons, and the polygons are mappeddirectly onto the graphics card which has built-in algorithms (openGLbased) for creating and updating geometry views.

For large space systems, the CAD file for the basic structure,panels, tanks, etc., is often 30 to 50 Mbytes. Conversion topolygons can require many hours (500 MHz, 512Mbyte memory), resultinginto a polygon file of 50 to 90 Mbytes. Screen rendering can requiremultiple seconds for each frame update; but the process works.

A major problem with interfacing a transport code to the CAD systemswas the fact that, internally, CAD systems are different. Furthermore, even using the standard STEP interface, new entitydefinitions are evolving. Table 1 lists the entities found in acurrent SYSTEM.STP STEP interface file. Table 2 indicates the

complexity of the linked data trees used for defining geometry withinthe STEP file. The table only shows the keyword linkage in the file,actual data has been omitted for clarity. Note that this samestructure is repeated, with data, for each object in the final model. Furthermore, this link tree was generated from a specific spacesystem model (MESSENGER) and does not include all the possiblebranches of the STEP object tree.

To bypass these obstacles, the CAD interface used in NOVICE worksdirectly from polygon files. To obtain the polygon file, acommercial viewer, STViewer (www.steptools.com), is used to parse theoriginal SYSTEM.STP file. After parsing, this viewer creates the twofiles used by NOVICE, namely SYSTEM.TREE and SYSTEM.GEOM. The TREEfile contains one line for each object indicating the object name anda transformation matrix (rotation and translation). Multipleinstances of the same object point to the single unique instance andhave different transformation matrices. The GEOM file contains thepolygons for every face of the unique objects, first instance only. Using these files, and new ray-trace algorithms, allows direct use ofthe CAD files in NOVICE.

Note, no screening of the CAD file to eliminate small parts,fasteners, fillets, etc., is done; the ray-tracing is still veryefficient on the large models. Basically, every object face andevery object instance is ‘boxed’ and bypassed during ray-tracing ifthe ray does not intercept the containing box.

In the example pictures, the colors of objects is determined by thediagonal length of the boxed object, <= 1" is color 1, <=2" is color2, <=4" is color 3, ..., <=128" is color 8. The usual practice is touse the material number (based on input order) as the color number. However, the STEP file has no record for indicating materialproperties. Another problem for radiation analysis is the absence ofdetail on portions of the geometry. For example, a system level CADfile will show structure, tanks, panels, and boxes. However, theboxes are often solids with, at best, a smeared density for accurate‘weight’ calculations. At the box level, the parts shown in thelayout are also solids with a mass or smeared density. Both of thesemodeling practices would lead to erroneous (low, not conservative)predictions of radiation levels if used directly in a radiationanalysis.

Therefore, a number of screening devices have been developed toperuse the CAD file for applicability, and several hooks have beenimplemented to accept modifications to the CAD model. Note, NOVICEhas always had the ability to accept geometry models from varioussources; this same capability applies to CAD files, i.e., multiple

CAD files can be used in a single analysis and the CAD files can bemixed with conventional solid geometry models using the othermodelers supported by NOVICE.

The quickest method for validating the CAD model is to generate andview a series of geometry frames. As mentioned, the polygon modelsalong with openGL support can produce a frame in seconds. However,radiation transport uses ray-trace analysis, and exercising the ray-tracing algorithms while generating views is an ideal validationmethod. Since the ray-tracing requires much more time, a number ofviews from different positions around the model are specified, andthe PC is left to complete the task. In generating the frames, thesystem also makes visible components transparent and repeats theframes until the entire system is transparent.

Additional checking is performed for each object in the model, andconsists of the following:1) generate a 3-D perspective view plus three cross-section viewscentered on and sized for each object in the CAD file;2) from the geometric center of each object, calculate the massthickness in the three orthogonal directions and output in a tableand as part of plotted picture legend; and3) for each object center, perform a SIGMA ray-trace analysis.Reviewing the output from these checkers will reveal most of theproblem areas in the model.

After perusing the figures and tables from the checking runs, variousfixes may be required before the CAD file is used in an analysis. Wherever possible, fixes are made at the NOVICE interface; requestingchanges from the CAD analyst is left as a last resort. At the NOVICEinterface, fixes to the model include a SYSTEM.MOD file thatspecifies the material and density for each of the CAD model objects. If the material designation is VOID, that part of the CAD model isthen ignored. A normal NOVICE model can then be placed in this area,e.g., a smeared CAD box can be replaced by an explicit box model(which may be another CAD file).

Currently, the SYSTEM.MOD file is the only mechanism available forspecifying the material names and densities for the objects in theCAD model; these data are not contained in the STEP file. Producingthe SYSTEM.MOD file is straight forward but if the STEP file containshundreds of objects, it is not pleasant, particularly since the datais already available within the CAD system. Furthermore, searchingout specific objects for critical review, e.g., is the smeareddensity correct for a honeycomb panel; which boxes are going to bereplaced by detailed modeling that includes electronics boards and

part layout; etc..

The following information would simplify the interfacing between CADand engineering analysis:

1) a generic object purpose, e.g., part, box, panel, tank, 2) the smeared density, g/cc, of the object, and3) the material name for the object.

This data could be specified in a separate text file, or as part ofthe textual information already included in the SYSTEM.STEP file. Table 3 lists part of the typical textual information extracted froma system level STEP file; one line for each object, with some objectsrepeated in the model 10 or 20 times; this specific model contains568 lines of this general form and most have been suppressed.

Using line ‘13' as an example (has #163395 as record ID):

#163395 '13' 'pjk2_bus_structure_assy_asm' 'pjk2_rear_panel'

The last string could be modified to read something like:

‘pjk2_rear_panel_RadTag_panel_.217_carbon-composite’

where RadTag indicates the start of information needed for radiationanalysis, “panel” identifies the object as a panel, the “.217" givesthe smeared density (g/cc) of the panel, and the “carbon-composite”identifies the generic material. If this type of textual informationwas supplied for each object, then it is a straight forward processto extract all the information needed to establish materialproperties–-the actual composition of carbon-composite would simplybe added to the NOVICE material library so that the composition wouldbe automatically retrieved from that library when needed fortransport physics data.

Similarly, line ‘559' (#481393 is record ID) contains:

! #481393 '559' 'messenger_satellite_asm' 'rf_pcu'

The ‘rf_pcu’ could have been supplied, for example as:

‘rf_pcu_RadTag_box_.272_boxsmear’

which identifies the object as a box (smeared in the CAD model),which makes it a candidate for removal from the CAD model withreplacement by a detailed model (RF_PCUBOX.MOD) or for leaving in themodel when doing detailed analysis on some other box. The .272 g/ccwould be used as the density with the box in the model, and boxsmear

would be a derived average composition for a box with contents, e.g.,some mixture of aluminum or magnesium for the box cover, polyimideand copper for boards and ground/signal planes, and ceramic, kovar,and silicon for electronics parts (or simply aluminum at reduceddensity for ray-trace analysis (actuals are not critical when thesmeared box has a second-order effect on the transport of radiationto some other box.)

NOTE: The use of a keyword such as RadTag allows the insertion of theextra text information at any point in the string making bothmodification of existing strings and subsequent parsing easier. Also, some CAD systems already have the capability of providing thematerial properties information, but this would vary by CAD systemprovider.

Table 1: Geometric Entities in a Typical SYSTEM.STP STEP File Count of First and Last This Type Record of Type Keyword Phrase for Record Type

124390 1 612693 --UNKNOWN: data or unassigned record type--- 61503 10 548410 direction 18193 11 548299 vector 172426 12 548408 cartesian_point 18193 13 548301 line 21653 17 612690 axis2_placement_3d 20837 54961 548317 vertex_point 4319 61623 548344 cylindrical_surface 65822 61624 548358 oriented_edge 14264 61637 548359 edge_loop 12552 61639 548360 face_outer_bound 12552 61640 548361 advanced_face 729 61851 512748 (bounded_surface 1020 62168 477857 b_spline_surface_with_knots 5631 62410 548356 plane 1712 62632 548131 face_bound 490 85487 537411 toroidal_surface 276 85892 541492 conical_surface 83 171992 543028 spherical_surface 223 237681 548362 closed_shell 217 237951 548363 manifold_solid_brep 439 237952 548397 dimensional_exponents 251 237953 548396 (length_unit 188 237954 548210 length_measure_with_unit 439 237955 548401 (conversion_based_unit 502 237957 548402 (named_unit 251 237958 548399 plane_angle_measure_with_unit 251 237962 548403 uncertainty_measure_with_unit 251 237965 548406 (geometric_representation_context 251 237970 548411 application_context 251 237972 548413 application_protocol_definition 251 237974 548415 design_context 251 237975 548416 mechanical_context 251 237976 548417 product 251 237978 548419 product_definition_formation_with_specified_source

569 237984 548393 item_defined_transformation 569 237988 548394 (representation_relationship 569 237989 548395 context_dependent_shape_representation 3 356486 499151 oriented_closed_shell 3 356487 499152 brep_with_voids 4 378383 379748 axis1_placement 4 378384 379749 surface_of_revolution 2 548421 548428 product_category 2 548422 548429 product_related_product_category 2 548427 548451 product_category_relationship 1 548452 548452 security_classification_level 1 548453 548453 security_classification 1 548454 548454 cc_design_security_classification 1 548537 548537 approval_status 1 548538 548538 approval 1 548539 548539 cc_design_approval 1 548590 548590 calendar_date 1 548591 548591 coordinated_universal_time_offset 1 548592 548592 local_time 1 548593 548593 date_and_time 1 548594 548594 approval_date_time 2 548595 548622 date_time_role 2 548596 548623 cc_design_date_and_time_assignment 1 548624 548624 person 1 548625 548625 organization 1 548626 548626 person_and_organization 1 548627 548627 approval_role 1 548628 548628 approval_person_organization 4 548629 548712 person_and_organization_role 4 548630 548713 cc_design_person_and_organization_assignment 9510 548740 612674 circle 5212 548741 612068 b_spline_curve_with_knots 32911 562129 612680 edge_curve 209 569320 612682 advanced_brep_shape_representation 251 569321 612691 product_definition 820 569322 612688 product_definition_shape 251 569323 612685 shape_definition_representation 42 569327 612616 shape_representation 569 569329 612686 next_assembly_usage_occurrence

Table 2: Tree Structure for a Geometric Entity (STEP)

Link Level Key Word Link Name

1 context_dependent_shape_representation 2 (representation_relationship 3 shape_representation 4 axis2_placement_3d 5 cartesian_point 5 direction 4 (geometric_representation_context 5 uncertainty_measure_with_unit 6 (conversion_based_unit 7 length_measure_with_unit 8 (length_unit 7 dimensional_exponents 7 plane_angle_measure_with_unit 8 (named_unit 6 (length_unit 5 (conversion_based_unit 6 length_measure_with_unit 7 (length_unit 6 dimensional_exponents 6 plane_angle_measure_with_unit 7 (named_unit 5 (named_unit 5 (length_unit 3 advanced_brep_shape_representation 4 axis2_placement_3d 5 cartesian_point 5 direction 4 manifold_solid_brep 5 closed_shell 6 advanced_face 7 face_outer_bound 8 edge_loop 9 oriented_edge 10 edge_curve 11 vertex_point

12 cartesian_point 11 line 12 cartesian_point 12 vector 13 direction 11 circle 12 axis2_placement_3d 13 cartesian_point 13 direction 11 b_spline_curve_with_knots 12 cartesian_point 7 cylindrical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 (bounded_surface 8 cartesian_point 7 b_spline_surface_with_knots 8 cartesian_point 7 plane 8 axis2_placement_3d 9 cartesian_point 9 direction 7 face_bound 8 edge_loop 9 oriented_edge 10 edge_curve 11 vertex_point 12 cartesian_point 11 line 12 cartesian_point 12 vector 13 direction 11 circle 12 axis2_placement_3d 13 cartesian_point 13 direction 11 b_spline_curve_with_knots 12 cartesian_point 7 toroidal_surface

8 axis2_placement_3d 9 cartesian_point 9 direction 7 conical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 spherical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 surface_of_revolution 8 b_spline_curve_with_knots 9 cartesian_point 8 axis1_placement 9 cartesian_point 9 direction 4 (geometric_representation_context 5 uncertainty_measure_with_unit 6 (conversion_based_unit 7 length_measure_with_unit 8 (length_unit 7 dimensional_exponents 7 plane_angle_measure_with_unit 8 (named_unit 6 (length_unit 5 (conversion_based_unit 6 length_measure_with_unit 7 (length_unit 6 dimensional_exponents 6 plane_angle_measure_with_unit 7 (named_unit 5 (named_unit 5 (length_unit 4 brep_with_voids 5 closed_shell 6 advanced_face 7 face_outer_bound 8 edge_loop 9 oriented_edge

10 edge_curve 11 vertex_point 12 cartesian_point 11 line 12 cartesian_point 12 vector 13 direction 11 circle 12 axis2_placement_3d 13 cartesian_point 13 direction 11 b_spline_curve_with_knots 12 cartesian_point 7 cylindrical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 (bounded_surface 8 cartesian_point 7 b_spline_surface_with_knots 8 cartesian_point 7 plane 8 axis2_placement_3d 9 cartesian_point 9 direction 7 face_bound 8 edge_loop 9 oriented_edge 10 edge_curve 11 vertex_point 12 cartesian_point 11 line 12 cartesian_point 12 vector 13 direction 11 circle 12 axis2_placement_3d 13 cartesian_point 13 direction 11 b_spline_curve_with_knots

12 cartesian_point 7 toroidal_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 conical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 spherical_surface 8 axis2_placement_3d 9 cartesian_point 9 direction 7 surface_of_revolution 8 b_spline_curve_with_knots 9 cartesian_point 8 axis1_placement 9 cartesian_point 9 direction 5 oriented_closed_shell 6 closed_shell 7 advanced_face 8 face_outer_bound 9 edge_loop 10 oriented_edge 11 edge_curve 12 vertex_point 13 cartesian_point 12 line 13 cartesian_point 13 vector 14 direction 12 circle 13 axis2_placement_3d 14 cartesian_point 14 direction 12 b_spline_curve_with_knots 13 cartesian_point 8 cylindrical_surface 9 axis2_placement_3d

10 cartesian_point 10 direction 8 (bounded_surface 9 cartesian_point 8 b_spline_surface_with_knots 9 cartesian_point 8 plane 9 axis2_placement_3d 10 cartesian_point 10 direction 8 face_bound 9 edge_loop 10 oriented_edge 11 edge_curve 12 vertex_point 13 cartesian_point 12 line 13 cartesian_point 13 vector 14 direction 12 circle 13 axis2_placement_3d 14 cartesian_point 14 direction 12 b_spline_curve_with_knots 13 cartesian_point 8 toroidal_surface 9 axis2_placement_3d 10 cartesian_point 10 direction 8 conical_surface 9 axis2_placement_3d 10 cartesian_point 10 direction 8 spherical_surface 9 axis2_placement_3d 10 cartesian_point 10 direction 8 surface_of_revolution 9 b_spline_curve_with_knots

10 cartesian_point 9 axis1_placement 10 cartesian_point 10 direction 3 item_defined_transformation 4 axis2_placement_3d 5 cartesian_point 5 direction 2 product_definition_shape 3 product_definition 4 product_definition_formation_with_specified_source 5 product 6 mechanical_context 7 application_context 4 design_context 5 application_context 3 next_assembly_usage_occurrence 4 product_definition 5 product_definition_formation_with_specified_source 6 product 7 mechanical_context 8 application_context 5 design_context 6 application_context

Table 3: Typical Textual Information, SYSTEM.STP File

Record TRA Text on Placement Line Text on Product Line

! #159016 '0' 'payload_adapter_assy_asm' 'square_round_concept5'! #160681 '1' 'payload_adapter_assy_asm' 'spring_brackets_sep_system'! #160681 '2' 'payload_adapter_assy_asm' 'spring_brackets_sep_system'! #160681 '3' 'payload_adapter_assy_asm' 'spring_brackets_sep_system'! #160681 '4' 'payload_adapter_assy_asm' 'spring_brackets_sep_system'! #160757 '5' 'pjk2_bus_structure_assy_asm' 'payload_adapter_assy_asm'! #161323 '6' 'pjk2_bus_structure_assy_asm' 'pjk2_aft_deck'! #162056 '7' 'pjk2_bus_structure_assy_asm' 'pjk2_top_deck'! #162245 '8' 'pjk2_hat_section_asm' 'pjk2_oxidizer_support_panel'! #162511 '9' 'pjk2_hat_section_asm' 'pjk2_oxidizer_panel'! #162842 '10' 'pjk2_hat_section_asm' 'pjk2_side_panel'! #163105 '11' 'pjk2_hat_section_asm' 'pjk2_side_panel2'! #163142 '12' 'pjk2_bus_structure_assy_asm' 'pjk2_hat_section_asm'! #163395 '13' 'pjk2_bus_structure_assy_asm' 'pjk2_rear_panel'! #163650 '14' 'pjk2_bus_structure_assy_asm' 'pjk2_rear_support_panel'! #163905 '15' 'pjk2_bus_structure_assy_asm' 'pjk2_rear_support_panela' ... lines 16 through 555 suppressed! #481707 '556' 'messenger_satellite_asm' 'rf_power_amp'! #482021 '557' 'messenger_satellite_asm' 'transponder'! #482712 '558' 'messenger_satellite_asm' 'rf_diplexer-switch'! #481393 '559' 'messenger_satellite_asm' 'rf_pcu'! #481707 '560' 'messenger_satellite_asm' 'rf_power_amp'! #482021 '561' 'messenger_satellite_asm' 'transponder'! #482712 '562' 'messenger_satellite_asm' 'rf_diplexer-switch'! #482930 '563' 'messenger_satellite_asm' 'rf_bracket_hybrid-coupler'! #487960 '564' 'higainassy_asm' 'anthg'! #488294 '565' 'higainassy_asm' 'ant_bracket'! #200765 '566' 'higainassy_asm' 'fbantassy_asm'! #488341 '567' 'messenger_satellite_asm' 'higainassy_asm'! #488459 '568' 'messenger_satellite_asm' '5_3kg_instrument_mass'

Appendix A:

This Appendix summarizes the current status of CAD interface activitiesrelative to NOVICE. The interface is currently working but requires additionaldevelopment for routine use. Much of the additional development is completedbut requires integration before a final product can be released, e.g., severalstand-alone codes are used for verification and checkout of the interface;these need to be integrated into a consistent graphical user interface.

Sections in the main document are:nomenclatureacronymsacknowledgmentsreferencessample STEP filesNOVICE modificationsstand-alone interface codessample NOVICE data for input and plot, andsample Index.PCM GUI input file

Appendix A contains various graphics files produced from the current interfaceusing the NOVICE ray-tracing as modified to incorporate ‘bounded surface’geometry modeling from STEP files. These are NOT graphics files from theOpenGL viewers used in the development of the interface.

Nomenclature for this document:

Object: a NOVICE region, a MCNP cell, an ITS zone, a body with materialcomposition and a ‘transformation’.

Transformation: a general combination of translations and rotations used tomove (relocate) a geometric entity to a different location with a differentorientation.

Body: a relocatable object

Shell: the surfaces forming the boundary of a body

Surface: the usual concept, hopefully analytic (function of x,y,z) but possiblyimplicit as NURBS, i.e., 3D control points plus spline interpolationprocedures.

Bounded Surface: the usual surfaces with boundaries. The boundaries areusually the intersection(s) with other surfaces but are represented by linesegments of varies types (straight, circular arcs, B-splines, ...). A boundedsurface has a single ‘outside’ boundary loop, and may have one or more ‘inside’boundary loops.

Polygons: here restricted to 3 (or 4) sided, convex (any 2 points in thepolygon are connected by a straight line which lies within the polygon), withall corners in a single plane.

Acronyms:

ACIIS, Spatial Technologies geometry modeler format, .SAT files.

GUI, graphical user interface.

IGES, initial graphics exchange specification, .IGS files.

IV, open InVenter?, SGI (Silicon Graphics), .IV files note: IV files are, for practical purposes, identical to WRL.

NURBS, non-uniform rational B-splines.

OGL, open graphics library, Silicon Graphics.

PDES, product data exchange using STEP.

STEP, STandard for the Exchange of Product model data, .STP files.

VRML, virtual reality modeling language, .WRL files.

Acknowledgments:

1) AES, Aerojet ElectroSystems (Don Toomb/Dave Love), looking at GEOMODinterface (a long time ago), and simple ProE neutral file examples.

2) GSFC, Goddard Space Flight Center (Janet Barth), funding for an interfaceto IDEAS produced IGES files.

3) COMDEV Inc. (Ibrahim Saleh/Kam Man), impetus for ProE neutral and STEPinterface.

4) OSC, Orbital Sciences Corp (John Walsh/Barry Posey), impetus for STEP andSAT (AutoCad 3D Modeler) interface.

5) Step Tools, Inc. (Blair Downie), ST-Viewer which produces beautifullyformatted polygon files from general STEP files; also produces VRML and IVfiles.

6) Actify Inc. (Mike Burton), 3D-View, creates VRML files from IGES files.

7) Lahey, Fortran 90 and 95 compilers

8) ISS, Interactive Software Services, Winteracter Library for windows andgraphics interfaces, superset of Lahey libraries.

9) William F. Mitchell, NIST, OGL to Fortran interface used by ISS/Lahey.

References:

1) NISTIR 4412, The Initial Graphics Exchange Specification (IGES) Version 5.0

2) ANS US PRO/IPO-200-042-1994, Product Data Exchange using STEP(PDES), Part42-Integrated Generic Resources: Geometric and Topological Representation. Alsoparts 21, 41, 203, ...

3) Piegl and Tiller, The NURBS Book.

4) Kempf and Frazier, OpenGL Reference Manual.

5) Woo, Neider, and Davis, OpenGL Programming Guide.

6) Wright and Sweet, OpenGL superbible.

7) Ames, Nadeau, and Moreland, VRML Sourcebook.

8) Carey and Bell, The Annotated VRML 2.0 Reference Manual.

Sample Files:

1) DETECTOR.IGS, GSFC, an IGES formatted file, also in STEP format butincompatible with ST-Viewer, a small detector system.

2) REALSTEP.STP, COMDEV, a STEP formatted file, also in ProE neutral fileformat, an electronics box.

3) 3DSAT.SAT, OSC, OV4 satellite model, converted to STEP format by Steptoolsusing their commercial SAT to STEP converter (3DSAT.STP)

4) ANTENNA.STP, OSC, antenna model in STEP format.

5) COMBOXES.STP, OSC, communications boxes in STEP format.

6) BATTERYS.STP, OSC, battery panels in STEP format.

7) *.STVIEW\*.TREE, hidden directory geometry tree file produced by ST-Viewerfrom STEP file named *.STP, e.g., 3DSAT.STVIEW\3DSAT.TREE.

8) *.STVIEW\*.GEOM, hidden directory geometry polygon file produced by ST-Viewer from STEP file named *.STP. This file contains a concise descriptionof the geometry hierarchy from explicit object (body with transformation),bodies, advanced faces, and polygons.

9) *.WRL, VRML formatted files produced by ST-Viewer from *.STP files, or by3DVIEW for *.IGS files. Both companies have additional conversioncapabilities.

NOVICE Hooks/Modifications:

1) *IGES, an interface for reading and plotting .IGS files:includes subprograms for ray-tracing NURBS surfaces.

2) *PROE, an interface for reading ProE neutral files with *.MOD files formodifications where needed including auto generation of point or volumedetectors inside indicated objects.

3) *STEP, an interface for reading the *.STVIZ\*.TREE and *.GEOM files producedby ST-Viewer.

4) *PICTURE,&I,&A,-D,&M,&X,&Y,&Z (maybe more)used to verify geometry model using NOVICE ray-trace algorithms.

&B, automatic XY, YZ, and ZX cross section views sized for center of eachregion, one plot per region.

&A, with &B, one plot for each STEP region only.

-D, automatic transparency for visibles, and repeat plot.

&M=m, m equally spaced plots around Z axis before next -D repeat.

&I, put region (object) indices on plot.

&X=x, x equal spaced YZ cross section views from Xmin to Xmax.&Y=y and &Z=z, same idea.

5) *DESIGN,G: generate polygon file from input lines.

6) *MAGIC,G: generate polygon file from input lines.

7) *MEVDP,G: generate polygon file from input lines.

8) *WIREFRAME: plot wireframe/filled polygon geometry views, with userinteraction (old style, not OpenGL).

9) *CSG: input/output constructive solid geometry files in various formatsincluding ITS3/ACCEPT.

10) *MCNP: input/output surface/region data, compositions, ... in MCNP formats.

11) *REPAIR: quick CAD repairs, change sense of face, turn off objects by STEPfile entity ID number.

12) *VIRTUAL: define and load unused geometric entity sets before *EXE, defineabsolutes from virtuals after *EXE.

Stand-Alone Processors Used for the Interface:

PCMASTER: a graphical user interface, generally linked lists oriented (likeHTML) but specific to generating input for and reviewing output from NOVICE andother radiation transport codes such as MCNP, ITS, CEPXS/ONELD, GEANT, ...

BOXFACES: reads *.TREE/GEOM files and produces *.PCM files. The *.PCM filesinclude a master file (the tree file) plus individual files for each object (tosimplify the modification step). Also produces a *.DET file containing centerpoints of each object to simplify an automatic ray-trace/sector analysis (anexercising of the geometry model).

WIREPLOT: an OpenGL plotter, a modification of the Winteracter TEAPOT, thatreads NOVICE polys, *.PCM polys, *.TREE/GEOM polys, and or VRML polys.Includes auto loops to generate plot files for each object in the model, peelobjects based on size or complexity, etc...

PARSESAT: parses a *.SAT file to obtain object, shell, face, loop, edge, etc.information.

STEPDATA: parses a *.STP file to obtain object, shell, face, loop, edge, etc.information.

Sample NOVICE Input for Using 3 CAD files with plotting:

*label/,’Sample problem combining three CAD files’/

*arrays,a/,control 33 -3/ Overlap from outside in

*files/0 '.N:\PDESSTEP\ANTENNAS\' / Path for first CAD file

*ROTATE,I=0,N=ANTENNAS/ Placement of first fileTRANSLATE 0 0 200/

*STEP,N=ANTENNAS,r=-1,t=aluminum/ Input first file

*files/0 '.N:\PDESSTEP\BATTERYS\' / Path for second CAD file

*ROTATE,I=0,N=BATTERYS/ Placement of second fileTRANSLATE 0 0 -200/

*STEP,N=BATTERYS,r=-1,t=silicon/ Input second file

*files/0 '.N:\PDESSTEP\COMBOXES\' / Path for third file

*ROTATE,I=0,N=COMBOXES/ Placement of third fileTRANSLATE 0 0 0 /

*STEP,N=COMBOXES,r=-1,t=water/ Input third file

*ROTATE,I=0/ Turn off rotates

*EXECUTE/ Input completed

*pic,q,d=-1,&m=8/ Auto peel, auto rotate,/ Auto size

*stop/ Finished

Sample Index.PCM File

c*****3dsat.PCM item sh068223 STEP body&get sh068223.PCMhelp Object faces: 8 0.250 8.563 Object polys: 576 8.563 2.274 0.250 Object limit: -1.640 6.923 -7.468 -5.194 -13.875 -13.625 item sh068224 STEP body&get sh068224.PCMhelp Object faces: 12 0.250 14.969 Object polys: 960 14.969 2.274 0.250 Object limit: -1.640 13.330 12.788 15.062 -13.875 -13.625 item sh068225 STEP body&get sh068225.PCMhelp Object faces: 37 19.184 21.575 Object polys: 2976 21.575 20.512 19.184 Object limit: -5.055 16.520 -6.458 14.054 -19.593 -0.409 item sh068226 STEP body&get sh068226.PCMhelp Object faces: 172 0.625 6.900 Object polys: 4000 6.900 0.625 5.810 Object limit: 2.394 9.294 -12.667 -12.042 -14.500 -8.690

... multiple objects removed from this file item sh068579 STEP body&get sh068579.PCMhelp Object faces: 16 0.250 0.707 Object polys: 768 0.250 0.367 0.707 Object limit: 23.642 23.892 4.245 4.612 33.897 34.603 item sh068580 STEP body&get sh068580.PCMhelp Object faces: 16 0.250 0.707 Object polys: 768 0.250 0.367 0.707 Object limit: 23.642 23.892 4.245 4.612 31.896 32.603 MaxTot faces: 476 29354 41.500 57.113 MaxTot polys: 22540 968006 41.500 44.323 57.113 System limit: -14.905 26.595 -18.903 25.420 -19.593 37.520