Difference between revisions of "User:Bhollister/Proposal"
Bhollister (talk | contribs) (GSoC 2015 Proposal) |
Bhollister (talk | contribs) |
||
| Line 1: | Line 1: | ||
| − | + | = Title = | |
| + | |||
| + | Command-line Editing NMG and BoT Data-structures in BRL-CAD | ||
| + | |||
| + | = Abstract = | ||
| + | |||
| + | This project will expose some of the low-level NMG routines to a command-line interface. Users will be able to add and remove various parts of the NMG data structure, such as regions and shells, along with manipulation of vertices, edges, and faces. A similar set of command-lines will allow for manipulation of "Bag of Triangles" (BoT) data-structures. Users will see the results displayed in either MGED or Archer. | ||
| + | |||
| + | Additional info: http://people.ucsc.edu/~behollis/hollisterGSoC2015Revised2.pdf | ||
| + | |||
| + | = Benefits to BRL-CAD = | ||
| + | BRL-CAD will gain a command-line interface for directly editing NMG / BoT data- | ||
| + | structures via Archer. The new features will be: | ||
| + | * Ability to select subsets of an NMG / BoT via the command-line. | ||
| + | * Ability to add and remove elements of an NMG / BoT while still satisfying validity constraints through the command-line. | ||
| + | * Ability to move parts of an NMG / BoT via the command-line. | ||
| + | * Visual feedback in the geometry window. | ||
| + | |||
| + | = Deliverables = | ||
| + | The implementation will consist of C code integrated with relevant modules | ||
| + | (/librt/primitives/nmg/, etc.). | ||
| + | |||
| + | = Project Details = | ||
| + | |||
| + | The fundamental data-structure for boundary representation in BRL-CAD is | ||
| + | the NMG. It is an implementation of a radial-edge data-structure and does | ||
| + | not enforce manifold constraints on mesh data. Boolean operations are closed | ||
| + | under the B-rep data type, thus making the NMG the preferred representation | ||
| + | for BRL-CAD. | ||
| + | The NMG Library Interface [1] is fundamental to the functionality proposed | ||
| + | here. There are broad categories of function calls that allow a high-level manipulation of the NMG data-structure in BRL-CAD. The categories are: | ||
| + | * CONSTRUCTION ROUTINES; for example: nmg mm(), nmg mmr() | ||
| + | * DESTRUCTION ROUTINES; for example: nmg kill(), nmg kr() | ||
| + | * MANIPULATION ROUTINES; for example: nmg face g(), nmg face bb() | ||
| + | |||
| + | The NMG data-structure hierarchically stores the mesh by: regions → | ||
| + | shells → f aces → loops → edges → vertices. Access into the data-structure | ||
| + | is provided by the high-level manipulation routines. For instance, when pro- | ||
| + | viding the ability of a table edit to change a vertex position, it will be nec- | ||
| + | essary to update the specific vertex in the table via the the nmg vertex gv() | ||
| + | routine. This routine requires a pointer to the vertex struct in the NMG data- | ||
| + | structure that represents the vertex. Other manipulation routines, such as | ||
| + | nmg ck closed surf(), i.e. “Check for a Closed Surface,” provide tools to enforce | ||
| + | various validation constraints. | ||
| + | |||
| + | The command-line functions will mirror the existing API, but expose as | ||
| + | much as possible. The interface may borrow some from the Blender low-level | ||
| + | API, using the following (see http://wiki.blender.org/index.php/Dev:2. | ||
| + | 6/Source/Modeling/BMesh/Design): | ||
| + | * BM vert createkill: Make Vert and Kill Vert | ||
| + | * BM edge createkill: Make Edge and Kill Edge | ||
| + | * BM face createkill: Make Face and Kill Face | ||
| + | * bmesh semvjekv: Split Edge, Make Vert and Join Edge, Kill Vert | ||
| + | * bmesh sfmejfke: Split Face, Make Edge and Join Face, Kill Edge | ||
| + | * bmesh loop reverse: Reverse the loop of a BMFace. Its own inverse | ||
| + | |||
| + | For roughly half of the summer, similar and appropriate command-line meth- | ||
| + | ods will be implemented for the BoT data-structure as well. | ||
| + | |||
| + | = Project Schedule = | ||
| + | |||
| + | Milestones: | ||
| + | * Week 1: Add placeholder commands by following example in commit 46507, which adds the exist command. Make sure that commands can be added and data is reflected internally. | ||
| + | * Week 2: Identify ways of specifying to the command-line the parts of model to be changed. For example, how to specify a vertex to a command that removes a vertex and update the NMG model in the render window. | ||
| + | * Week 3: Should be able to implement commands now. Allow two weeks to complete each type of command. Starting this week with NMG CONSTRUCTION ROUTINES. | ||
| + | * Week 4: NMG - 2nd week for CONSTRUCTION ROUTINES. | ||
| + | * Week 5: NMG - 1st week for DESTRUCTION ROUTINES. | ||
| + | * Week 6: NMG - 2nd week for DESTRUCTION ROUTINES. | ||
| + | * Week 7: NMG - 1st week for MANIPULATION ROUTINES. | ||
| + | * Week 8: NMG - 2nd week for MANIPULATION ROUTINES. | ||
| + | * Week 9: Start BoTs command-line command implementations. Starting this week with BoT CONSTRUCTION ROUTINES. | ||
| + | * Week 10: BoT - 2nd week for CONSTRUCTION ROUTINES. | ||
| + | * Week 11: BoT - 1st week for DESTRUCTION ROUTINES. | ||
| + | * Week 12: BoT - 2nd week for DESTRUCTION ROUTINES | ||
| + | * Week 13: BoT - 1st week for MANIPULATION ROUTINES. | ||
| + | * Week 14: BoT - 2nd week for MANIPULATION ROUTINES. Final fixes and clean-up. | ||
Revision as of 18:19, 22 May 2015
Contents
Title
Command-line Editing NMG and BoT Data-structures in BRL-CAD
Abstract
This project will expose some of the low-level NMG routines to a command-line interface. Users will be able to add and remove various parts of the NMG data structure, such as regions and shells, along with manipulation of vertices, edges, and faces. A similar set of command-lines will allow for manipulation of "Bag of Triangles" (BoT) data-structures. Users will see the results displayed in either MGED or Archer.
Additional info: http://people.ucsc.edu/~behollis/hollisterGSoC2015Revised2.pdf
Benefits to BRL-CAD
BRL-CAD will gain a command-line interface for directly editing NMG / BoT data- structures via Archer. The new features will be:
- Ability to select subsets of an NMG / BoT via the command-line.
- Ability to add and remove elements of an NMG / BoT while still satisfying validity constraints through the command-line.
- Ability to move parts of an NMG / BoT via the command-line.
- Visual feedback in the geometry window.
Deliverables
The implementation will consist of C code integrated with relevant modules (/librt/primitives/nmg/, etc.).
Project Details
The fundamental data-structure for boundary representation in BRL-CAD is the NMG. It is an implementation of a radial-edge data-structure and does not enforce manifold constraints on mesh data. Boolean operations are closed under the B-rep data type, thus making the NMG the preferred representation for BRL-CAD. The NMG Library Interface [1] is fundamental to the functionality proposed here. There are broad categories of function calls that allow a high-level manipulation of the NMG data-structure in BRL-CAD. The categories are:
- CONSTRUCTION ROUTINES; for example: nmg mm(), nmg mmr()
- DESTRUCTION ROUTINES; for example: nmg kill(), nmg kr()
- MANIPULATION ROUTINES; for example: nmg face g(), nmg face bb()
The NMG data-structure hierarchically stores the mesh by: regions → shells → f aces → loops → edges → vertices. Access into the data-structure is provided by the high-level manipulation routines. For instance, when pro- viding the ability of a table edit to change a vertex position, it will be nec- essary to update the specific vertex in the table via the the nmg vertex gv() routine. This routine requires a pointer to the vertex struct in the NMG data- structure that represents the vertex. Other manipulation routines, such as nmg ck closed surf(), i.e. “Check for a Closed Surface,” provide tools to enforce various validation constraints.
The command-line functions will mirror the existing API, but expose as much as possible. The interface may borrow some from the Blender low-level API, using the following (see http://wiki.blender.org/index.php/Dev:2. 6/Source/Modeling/BMesh/Design):
- BM vert createkill: Make Vert and Kill Vert
- BM edge createkill: Make Edge and Kill Edge
- BM face createkill: Make Face and Kill Face
- bmesh semvjekv: Split Edge, Make Vert and Join Edge, Kill Vert
- bmesh sfmejfke: Split Face, Make Edge and Join Face, Kill Edge
- bmesh loop reverse: Reverse the loop of a BMFace. Its own inverse
For roughly half of the summer, similar and appropriate command-line meth- ods will be implemented for the BoT data-structure as well.
Project Schedule
Milestones:
- Week 1: Add placeholder commands by following example in commit 46507, which adds the exist command. Make sure that commands can be added and data is reflected internally.
- Week 2: Identify ways of specifying to the command-line the parts of model to be changed. For example, how to specify a vertex to a command that removes a vertex and update the NMG model in the render window.
- Week 3: Should be able to implement commands now. Allow two weeks to complete each type of command. Starting this week with NMG CONSTRUCTION ROUTINES.
- Week 4: NMG - 2nd week for CONSTRUCTION ROUTINES.
- Week 5: NMG - 1st week for DESTRUCTION ROUTINES.
- Week 6: NMG - 2nd week for DESTRUCTION ROUTINES.
- Week 7: NMG - 1st week for MANIPULATION ROUTINES.
- Week 8: NMG - 2nd week for MANIPULATION ROUTINES.
- Week 9: Start BoTs command-line command implementations. Starting this week with BoT CONSTRUCTION ROUTINES.
- Week 10: BoT - 2nd week for CONSTRUCTION ROUTINES.
- Week 11: BoT - 1st week for DESTRUCTION ROUTINES.
- Week 12: BoT - 2nd week for DESTRUCTION ROUTINES
- Week 13: BoT - 1st week for MANIPULATION ROUTINES.
- Week 14: BoT - 2nd week for MANIPULATION ROUTINES. Final fixes and clean-up.
