TopMod 4.0 Design Revision (draft)

Fenghui Zhang

Goal

Clean up the design in TopMod, reduce the dependencies between modules/layers
Improve the readability and the maintainability of the system
Compress the core to reduce memory consumption
Improve performance
Support natural efficient Undo/Redo operation

Coding standard
This is not for the GUI parts which will possibly be generated from a GUI design tool

Compile a set of rules to be enforced in the system
- Comments
- Unit tests
- Proper spacing
- Line width limit (80)
- No implementations in header files
- Naming convention

TopMod System (GUI not included)

The Topological interface contains only minimum information to represent an topological object
- Adjacency list + Rotation system: The object only has a vertex list
  - Each vertex keeps a ordered list of its neighbors
  - Edges can be deduced from the adjacency list
  - Faces and corner can be obtained through face tracing algorithm
  - Note that we allow loops and multiple edges
- Operations supported
  - All basic operations can be reverted, this forms the base of the Undo operation, note that the IDs should never be changed or reused for the same object in order to make the undo successful.
  - Topological operations
    - Insert Vertex
      - Precondition
        None
      - Operation
        Insert a vertex at given position, assign an new ID to it
      - Postcondition
        There is a new vertex at the given position, the ID assigned should not been changed later
      - Reverse operation:
        Delete Vertex
    - Delete Vertex
      - Precondition
        There is a vertex with given ID
      - Operation
        Delete a vertex with given ID
      - Postcondition
        The ID is invalidated, and the ID is never to be used again by Insert Vertex
      - Reverse operation:
        Insert Vertex
    - Insert Edge
      - Precondition
        Two valid corners are given by ID
      - Operation
        Insert an edge between two given corners, assign an new ID to it
      - Postcondition
        There is an new edge added between the two corners, the ID assigned should not been changed later
      - Reverse operation:
        Delete Edge
    - Delete Edge
      - Precondition
        There is an edge with given ID
      - Operation
        Delete an edge with given ID
      - Postcondition
        The ID is invalidated, and the ID is never to be used again by Insert Edge
      - Reverse operation:
        Insert Edge
The Geometric interface contains minimum information to represent geometries
- Each vertex keeps its own Position information
- Operations supported
  - All basic operations can be reverted, this forms the base of the Undo operation, note that the IDs should never be changed or reused for the same object in order to support the undo/redo operations.
  - Geometrical operations
    - Move Vertex
      - Precondition
        There is a valid vertex given by ID
DLFL wrapper
- To be compatible with the previous version
- Contains a list of edges
- Contains a list of list of faces
The auxiliary layer contains extended operations (maybe callable from the GUI)
- Topological operations
  - Add hole/handle
  - Extrusion
  - Subdivisions
- Predefined objects
  - Cube, tetrahedron, etc.
The interactive layer contains all operations that related to GUI
- Undo/Redo
- Selection Operations
  - Edge loops, edge rings, etc.
- Load/Save to file
- Color face
- etc.
Renderable wrapper (patch modeling is not covered here)
- Contains information about normals for faces
Patch modeling wrapper
- Contains information needed for compute patches

Tools

The Tool layer contains the callable features from the GUI, we wrap all the callable operations defined in the TopMod system
Each tool is a class wrapping a feature of the interactive layer and the auxiliary layer
- The GUI sets parameters to the tool when the user changes the parameters in the ToolOptions panel
- When the user clicks the button, the GUI ask the tool to execute
Tools can also be wrapping external scripts or plugins
Each tool should specify the user-modifiable parameters either when requested or automatically
Adding a tool to the interface should preferably be accomplished by single function call

The "location" of the tool within the UI as well as the parameters that are associated with the tool can either be specified within the function call or within the class (which can be queried by the parent application)

TopMod 3.0 as an Onion

Display
- GUI - Renderable/patch modeling wrapper - DLFL wrapper - Geometric/Topological core
Operational
- GUI - Tools - interactive/auxiliary layer -DLFL wrapper - Geometric/Topological core
- QT related part (GUI) only contain the interactive logic:
  - Select vertex(ices), edge(s), face(s), corner(s)
  - Set tool options (parameters)
  - Apply a Tool
  - Set user preferences (change mode, show/hide information, etc.)

Tools connect GUI to the system
- Every Operation callable from the GUI is a Tool
  - Create prim shapes
  - Insert Edge, Delete Edge, Insert Vertex, Delete Vertex, Move vertex, etc.
  - Subdivisions
  - Extrusions
  - Add handles
  - etc.