Profile BREP/NURBS ray tracing

• Benefit: better ray tracing runtime understanding, supports test case development
• Time Estimate: 2 days
• References:
  • src/libbrep
  • src/librt/primitives/brep
  • src/librt/opennurbs_ext.*

Optimize BREP/NURBS prep

Perform limited tree splitting during prep, split dynamically during ray trace, store lock-free.

• Benefit: faster ray tracing throughput, user requested, user visible
• Time Estimate: 1 week
• References:
  • src/libbrep
  • src/librt/primitives/brep/brep.cpp:rt_brep_prep()
  • src/librt/opennurbs_ext.*

Convert existing entities to NURBS

Implement hooks to describe entities in BREP/NURBS form. Partially complete for most, but some complex entities remain unimplemented.

• Benefit: partial requirement for interactive visualization of implicit CSG geometry in OpenGL
• Time Estimate: 2 days per entity
• References:
  • src/librt/primitives/${PRIM}/${PRIM}_brep.cpp

BREP/NURBS-to-NMG

Implement conversion of BREP/NURBS to NMG.

• Benefit: requirement for polygonal export, partial requirement for OpenGL visualization, user visible
• Time Estimate: 2 days
• References:
  • src/librt/primitives/brep/brep.cpp:rt_brep_tess()

Old BSPLINE/NURBS review

Identify useful concepts implemented in the old BSPLINE/NURBS code that are not present in openNURBS.

• Benefit: code reuse, potentially very useful functionality.
• Time Estimate: 1 day
• References:
  • src/librt/primitives/bspline/*

BSPLINE/NURBS reuse

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