Editing User:Phoenix/GSoc2012/Reports

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 162: Line 162:
 
* July 17
 
* July 17
 
** Fit the points into NURBS curves using polyline approximation.
 
** Fit the points into NURBS curves using polyline approximation.
** TODO: (1) Calculate max_dis according to the size of the biggest bounding box. Tests are needed to define a better threshold. (done) (2) Implement a method to test SSI (maybe extend the brep command in MGED with an option "intersect"). (done)
+
** TODO: (1) Calculate max_dis according to the size of the biggest bounding box. Tests are needed to define a better threshold. (2) Implement a method to test SSI (maybe extend the brep command in MGED with an option "intersect").
 
* July 18
 
* July 18
 
** Fixed the copy crashing by using pointers to the intersection curves.
 
** Fixed the copy crashing by using pointers to the intersection curves.
Line 179: Line 179:
 
== Week 10 ==
 
== Week 10 ==
 
* July 23
 
* July 23
** Intersection with a plane surface works well now - for a BBNode with no children within the max depth, copy itself as its child. (An image of related results was uploaded.)
+
** Intersection with a planar surface works well now - for a BBNode with no children within the max depth, copy itself as its child.
* July 24
 
** There is a trade off between performance and result quality. If we use bigger INTERSECT_MAX_DEPTH (i.e, 10 instead of 8), we get better results but it costs more time.
 
** Calculated the coordinates of the intersection points in UV parameter spaces. The next step is to make use of these coordinates to create 2D trimming curves.
 
* July 25
 
** Do not generate the whole surface tree - only a small useful subset is generated simultaneously with the intersection process. Much faster.
 
** TODO: use the tolerance value instead of a constant INTERSECT_MAX_DEPTH.
 
* July 26
 
** Do not copy the node as its child - just pass it to the next iteration.
 
** Fixed the memory leak introduced by this morning's modification.
 
* July 27
 
** Calculated the intersection curves in UV parameter spaces (trimming curves), and extended the brep command to test them.
 
 
 
== Week 11 ==
 
* July 30
 
** Modified brep_debug.cpp to plot the 2D trimming polyline curves better. Used KnotCount - 1 as the plotres to avoid the interpolation problems.
 
* July 31
 
** Some minor changes to the b-rep conversion functions in brep_debug.cpp. Free the allocated spaces.
 
* Aug 1
 
** The first step of manipulating booleans on NURBS b-rep objects. Added a function to /primitives/brep/brep.cpp which is going to deal with the boolean operations of b-reps.
 
* Aug 2
 
** Added a function in to deal with NURBS curve-curve intersection, which will be useful in evaluating booleans on NURBS.
 
* Aug 3
 
** Continued work on evaluating booleans on NURBS - generate new trimmed faces with intersection curves (not all situations are considered now, still WIP).
 
== Week 12 ==
 
* Aug 6
 
** Continued working on dividing trimmed surfaces. It's really quite complicated. Lots of further work and tests are needed.
 
* Aug 7
 
** The current method for partitioning a trimmed surface is not elegant and convenient. Looked for some materials online and found some valuable resources.
 
** Used a new method for partitioning a surface. Followed the algorithms described in: S. Krishnan, A. Narkhede, and D. Manocha. BOOLE: A System to Compute Boolean Combinations of Sculptured Solids. Technical Report TR95-008. Department of Computer Science, University of North Carolina, 1995. Appendix B: Partitioning a Simple Polygon using Non-Intersecting Chains.
 
* Aug 8
 
** Finished a draft of partitioning a surface. Modifications for special cases and tests are needed.
 
** Before starting to write code dealing with inside-outside tests, which is the final step to evaluated NURBS, the current routine of partitioning should be finished beforehand. But it's still a long way to go. I hope I can have good luck with it.
 
* Aug 9
 
** Added an option to the brep command in MGED to test boolean evaluations (currently only "union").
 
** The evaluation processes are still WIP. The final b-rep structure cannot pass IsValid() at present because edges and vertices are not added. Besides, lots of other modifications are needed.
 
* Aug 10
 
** Added trims, vertices, edges, etc. to the b-rep structure and checked its validity.
 
== Week 13 ==
 
* Aug 13
 
** Continued working on adding elements to the ON_Brep structure, trying to make IsValid() succeed. Did some clean up and fixed some bugs, and make the common parts into a separate function.
 
** Today is the suggested "pencils down" date. As for the project of evaluating NURBS objects, I think I do not have enough time left to finish it all. At present, faces can be partitioned into several trimmed faces, but some conditions are not considered and problems may still exist. As for the week left, I'd like to go back to the code I wrote all these months, do some clean up, add necessary documents, etc.
 
* Aug 14
 
** Modified add_elements() and tried using the ON_Surface::Pushup() method first.
 
** Some clean up on dsp_brep.cpp: modified comments, renamed a variable with typo, eliminated the debug output, and reduced using dynamic allocated pointers.
 
** Added comment before surface_surface_intersection() to describe the algorithm used in SSI.
 
* Aug 15
 
** Modified cline_brep.cpp, ehy_brep.cpp, epa_brep.cpp, eto_brep.cpp and extrude_brep.cpp and eliminated the memory leak.
 
* Aug 16
 
** Modified hyp_brep.cpp, part_brep.cpp, pipe_brep.cpp, revolve_brep.cpp, rhc_brep.cpp, rpc_brep.cpp, sketch_brep.cpp and tgc_brep.cpp and eliminated the memory leak.
 
** Did some clean up and added comments to /libged/brep.c.
 
* Aug 17
 
** Add documentation of the brep command in MGED to the wiki page. See: [[http://brlcad.org/wiki/MGED_CMD_brep]]
 
== Final summary ==
 
* The "Implicit to NURBS conversion" project was mainly done before mid-term evaluation. The milestones and previous goals in the original proposal are finished.
 
* After mid-term, I focused on the "NURBS Intersection" project, and add many useful features to BRL-CAD, such as calculating surface-surface intersection curves (both in 3d space and 2d UV space), splitting surface and generating new trimmed surfaces, etc.
 
  
 
= Test Results =
 
= Test Results =
Line 266: Line 211:
 
* The intersection curves (green) of a tgc (red) and an epa (blue). (Two segments)
 
* The intersection curves (green) of a tgc (red) and an epa (blue). (Two segments)
 
[[Image:Tgc epa.png]]
 
[[Image:Tgc epa.png]]
* The intersection curve (green) of a plane surface (red) and an ehy (blue).
 
[[Image:Planar ehy.png]]
 
  
 
= Original development timeline =
 
= Original development timeline =

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)