Editing NURBS Booleans

From BRL-CAD

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision Your text
Line 1: Line 1:
Non-Uniform Rational B-Splines are the dominant geometric representation format in Computer Aided Design.  BRL-CAD's support for these primitives is relatively recent, and while we can raytrace them we are still developing the ability to perform operations such as subtraction and intersection between two solid NURBS Boundary Representations (Breps).  This ability is fundamental to a wide variety of editing operations and essential to the process of converting implicit-primitive based boolean geometry trees to evaluated NURBS models.
+
{| border=1 align="right"
 +
!Impact
 +
!Difficulty
 +
|-
 +
|high
 +
|hard
 +
|}
  
This task would build on work done in previous GSoC projects to make existing functionality robust and fast.
+
Non-Uniform Rational B-Splines are the dominant geometric representation format in Computer Aided Design.  BRL-CAD's support for these primitives is relatively recent, and while we can raytrace them we do not have the ability to perform operations such as surface/surface intersection calculations.  These abilities are fundamental to a wide variety of editing operations and essential to the process of converting implicit-primitive based boolean geometry trees to evaluated NURBS models.
 +
 
 +
This task would target the problem of implementing an algorithm to calculate surface/surface intersection for general NURBS surfaces.  These guys implemented something very similar although their implementation was not robust: http://www.cs.unc.edu/~geom/CSG/boole.html These guys followed that work and implemented a robust solution, but killed performance: http://www.cs.unc.edu/~geom/ESOLID/ You will need to be very careful about tolerances and tolerance tracking without resorting to fixed-precision arithmetic. There are a variety of other research papers on the surface/surface intersection problem - students interested in this topic should discuss it with developers on the IRC channel or via email.
  
 
=References=
 
=References=
  
* src/libbrep
 
 
* src/librt/primitives/brep
 
* src/librt/primitives/brep
 +
* src/librt/primitives/bspline
 
* src/other/openNURBS
 
* src/other/openNURBS
 +
* src/librt/opennurbs_ext.*
 +
* include/opennurbs_ext.h
 
* include/raytrace.h
 
* include/raytrace.h
 
* include/rtgeom.h
 
* include/rtgeom.h
 
* http://brlcad.org/wiki/User:Phoenix/GSoc2013/Reports
 
  
 
=Requirements=
 
=Requirements=

Please note that all contributions to BRL-CAD may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see BRL-CAD:Copyrights for details). Do not submit copyrighted work without permission!

To edit this page, please answer the question that appears below (more info):

Cancel Editing help (opens in new window)