Editing NURBS TODO

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= Profile BREP/NURBS ray tracing=
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* Optimize BREP/NURBS ray tracing
* Benefit: better ray tracing runtime understanding, supports test case development
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** Benefit: faster ray tracing runtime
* Time Estimate: 2 days
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* Optimize BREP/NURBS prep
* References:
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** Benefit: faster ray tracing runtime, user requested.
** src/libbrep
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* Implement conversion of implicit primitives to BREP/NURBS primitives.
** src/librt/primitives/brep
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** Partially complete, primitives are fixed at origin, some primitives unimplemented.
** src/librt/opennurbs_ext.*
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** Benefit: partial requirement for interactive visualization of implicit CSG geometry in OpenGL.
 
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* Implement conversion of BREP/NURBS to NMG.
= Optimize BREP/NURBS prep=
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** Benefit: partial requirement for export and interactive visualization of BREP/NURBS in OpenGL.
Perform limited tree splitting during prep, split dynamically during ray trace, store lock-free.
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* Identify useful concepts implemented in the old BSPLINE/NURBS code that are not present in openNURBS.
* Benefit: faster ray tracing throughput, user requested, user visible
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** Benefit: code reuse, potentially very useful functionality.
* Time Estimate: 1 week
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* Port any useful BSPLINE/NURBS code to openNURBS data structures and routines.
* References:
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** Benefit: code reduction, allows the old BSPLINE/NURBS code to be removed after functionality is migrated.
** src/libbrep
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* Implement boolean evaluation of BREP/NURBS surfaces.
** src/librt/primitives/brep/brep.cpp:rt_brep_prep()
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** Benefit: partial requirement for interactive visualization of BREP/NURBS in OpenGL.
** src/librt/opennurbs_ext.*
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* Implement plate mode BREP/NURBS objects.
 
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** Similar, if not identical, to plate mode BoTs, 'brep' objects need the ability to have a thickness described so you could automatically handle non-solid NURBS and sheet-metal style geometry without requiring surface solidity.
= Convert existing entities to NURBS=
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** Benefit: allows for import and visualization of BREP/NURBS surfaces that are not solid.
Implement hooks to describe entities in BREP/NURBS form. Partially complete for most, but some complex entities remain unimplemented.
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* Develop test scripts for comparing conversion of implicit CSG to BREP/NURBS CSG
* Benefit: partial requirement for interactive visualization of implicit CSG geometry in OpenGL
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** Benefit: provides validation and verification via ray tracing.
* Time Estimate: 2 days per entity
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* Document the new BREP/NURBS primitive.
* References:
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** Benefit: provides user documentation explaining capabilities, limitations, and benefits.
** src/librt/primitives/${PRIM}/${PRIM}_brep.cpp
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* Implement data cache objects.
 
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** Create new LIBRT API routines for storing cache data in a v5 container.  This would amount to storing binary data into a 'binunif' object marked as hidden with attributes for date/time stamping and MD5 or SHA256 checksumming.
= BREP/NURBS-to-NMG=
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** Benefit: faster ray tracing runtime, applicable to other primitives (NMG, BoT).
Implement conversion of BREP/NURBS to NMG.
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* Cache BREP/NURBS prep results to a specified cache file.
* Benefit: requirement for polygonal export, partial requirement for OpenGL visualization, user visible
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** Benefit: faster ray tracing runtime for BREP/NURBS, user requested.
* Time Estimate: 2 days
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* Improve BREP/NURBS wireframe.
* References:
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** Investigate using knots on subcurves.
** src/librt/primitives/brep/brep.cpp:rt_brep_tess()
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** Benefit: faster wireframe, more detailed close wireframes.
 
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* BREP/NURBS source code cleanup.
= Old BSPLINE/NURBS review=
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** Consolidate Owens and Reeves approaches to ray intersection.
Identify useful concepts implemented in the old BSPLINE/NURBS code that are not present in openNURBS.
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** Benefit: improved code maintainability.
* Benefit: code reuse, potentially very useful functionality.
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* Implement an rt_heal(rt_db_internal *dbi); routine.
* Time Estimate: 1 day
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** The routine tightens up trimming curves and edge/vertex pairings so that they align perfectly while still preserving the topological structure.
* References:
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* Write an report on using NURBS for analysis purposes.
** src/librt/primitives/bspline/*
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* Perform analytic comparison of BREP/NURBS and BoT geometry
 
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* Perform analytic comparison of BREP/NURBS CSG and implicit CSG geometry
= BSPLINE/NURBS reuse=
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* Implement support for rotation, scaling, and translations.
Port any useful BSPLINE/NURBS code to openNURBS data structures and routines.
 
* Benefit: code reduction, allows the old BSPLINE/NURBS code to be removed after functionality is migrated.
 
* Time Estimate: 2 days
 
* References:
 
** src/librt/primitives/bspline/*
 
** src/librt/primitives/brep/*
 
 
 
=BREP/NURBS CSG evaluation=
 
Implement boolean evaluation of BREP/NURBS surfaces.
 
* Benefit: partial requirement for interactive visualization of BREP/NURBS in OpenGL.
 
* Time Estimate: 2 years (for 100% robustness)
 
* References:
 
** ESOLID: http://research.cs.tamu.edu/keyser/geom/esolid/
 
** http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.119.4341&rep=rep1&type=pdf
 
** http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.117.8700&rep=rep1&type=pdf
 
** http://www.springerlink.com/content/x3665206243u20x8/
 
** http://193.170.37.128/projects/basic/cgal/workdone/nurbs-97-30.ps.gz
 
** http://mae.ucdavis.edu/~farouki/foils.pdf
 
** http://portal.acm.org/citation.cfm?id=36714
 
** ftp://ftp.cs.unc.edu/pub/users/manocha/PAPERS/INTERSECT/IJCGA.pdf
 
** http://portal.acm.org/citation.cfm?id=237751
 
 
 
=Implicit CSG to BREP/NURBS CSG test scripts=
 
Develop test scripts for comparing conversion of implicit CSG to BREP/NURBS CSG
 
* Benefit: provides validation and verification via ray tracing.
 
* Time Estimate: < 1 day
 
* References:
 
** regress/*.sh
 
** sh/*.sh
 
 
 
=BREP/NURBS documentation=
 
Document the new BREP/NURBS primitive (user overviewdocumentation: how to import, use, export, limitations).
 
* Benefit: provides user documentation explaining capabilities, limitations, and benefits; user visible
 
* Time Estimate: 3 days
 
* References:
 
** doc/docbook/articles
 
 
 
=BREP/NURBS wireframe=
 
Improve BREP/NURBS wireframe. Investigate using knots on subcurves.
 
* Benefit: faster wireframe; LOD wireframes: more detailed close-up wireframes, less detailed far-away wireframes (LOD); user visible
 
* Time Estimate: 2 days
 
* References:
 
** http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.142.3042&rep=rep1&type=pdf
 
** http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.70.6138&rep=rep1&type=pdf
 
** http://www.springerlink.com/content/k7543860533338nu/
 
** http://wscg.zcu.cz/wscg2003/Papers_2003/H19.pdf
 
** http://cg.cs.uni-bonn.de/aigaion2root/attachments/kahlesz-2002-multiresolution.pdf
 
** http://www.cs.cityu.edu.hk/~rynson/papers/vrst03.pdf
 
** http://www.flipcode.com/archives/NURBS_Curves_Surfaces.shtml
 
 
 
= BREP/NURBS source code cleanup=
 
Consolidate Owens and Reeves approaches to ray intersection.
 
* Benefit: improved code maintainability, complexity reduction
 
* Time Estimate: 2 days
 
* References:
 
** http://www.cs.utah.edu/~shirley/papers/raynurbs.pdf
 
 
 
= BREP/NURBS healing=
 
Implement an rt_heal(rt_db_internal *dbi); routine. The routine tightens up trimming curves and edge/vertex pairings so that they align perfectly while still preserving the topological structure.
 
* Benefit: more robust evaluation for improved (more stable & consistent) raytracing, import, export; routine interface later applicable to NMG/BoT too
 
* Time Estimate: 3 days
 
* References:
 
** src/librt/primitives/brep
 

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