Extensions:2.6/Py/Scripts/Add Mesh/Data Surface/Text Data Surface

Script Detail

This page is to explain how Data Surface addon works.

The key files to this addon are two python scripts: __init__.py and add_mesh_text_data_surface.py.

__init__.py

In __init__.py, these scripts declare the information of this addon.

bl_info = {
  "name": "3D Surfaces from Data Files",
  "author": "Sun Sibai (niasw) <niasw@pku.edu.cn>, Pontiac",
  "version": (1, 0),
  "blender": (2, 71, 0),
  "location": "View3D > Add > Mesh",
  "description": "Create Object using Data Files.",
  "wiki_url": "https://github.com/niasw/add_mesh_DataSurface",
  "category": "Add Mesh"
}

these scripts define the menu shown in 3D View when pressing Shift+a.

class INFO_MT_mesh_data_surface_add(bpy.types.Menu):
  bl_idname = "INFO_MT_mesh_data_surface_add"
  bl_label = "Data Surface"

  def draw(self, context):
    layout = self.layout
    layout.operator_context = 'INVOKE_REGION_WIN'
    layout.operator("mesh.primitive_text_data_surface",
           text="Text Data Surface")

def menu_func(self, context):
  self.layout.menu("INFO_MT_mesh_data_surface_add", icon="PLUGIN")

add_mesh_text_data_surface.py

In add_mesh_text_data_surface.py, this is the main class.

class AddTextDataSurface(bpy.types.Operator):
    bl_idname = "mesh.primitive_text_data_surface"
    bl_label = "Add Text Data Surface"
    bl_options = {'REGISTER', 'UNDO', 'PRESET'}

    ...

    def execute(self, context):
        ...

When adding the mesh object or editing parameters, execute method will be called for each operation.

The input parameters are also defined in this class.

class AddTextDataSurface(bpy.types.Operator):
    ...

    xFile = StringProperty(name="Data File of X(U,V)",
        description="U,V: index coordinates of nodes; X: x coordinate of nodes. (Matrix Text)",
        default=addon_utils.paths()[0]+"/add_mesh_DataSurface/Xdata.txt", subtype="FILE_PATH")
    yFile = StringProperty(name="Data File of Y(U,V)",
        description="U,V: index coordinates of nodes; Y: y coordinate of nodes. (Matrix Text)",
        default=addon_utils.paths()[0]+"/add_mesh_DataSurface/Ydata.txt", subtype="FILE_PATH")
    zFile = StringProperty(name="Data File of Z(U,V)",
        description="U,V: index coordinates of nodes; Z: z coordinate of nodes. (Matrix Text)",
        default=addon_utils.paths()[0]+"/add_mesh_DataSurface/Zdata.txt", subtype="FILE_PATH")
    loop = BoolProperty(name="Loop in U Direction",
        description="Loop in U direction or not?",
        default=False)
    flip = BoolProperty(name="Flip Normal Vector",
        description="Flip the normal vector of surfaces or not?",
        default=False)

    ...

When calling the execute, several auxiliary methods will be called in execute.

The 1st aux-method is to acquire matrix data from text files. The Xdata.txt in the previous example (on Data Surface wikipage) is an instance of these text data files.

# Load data from plain text file (in matrix format)
# Return uNum, vNum, dataList
#   filename ... plain text file of data (in matrix format)
#   uNum ... number of vertices in U direction (horizontal in matrix)
#   vNum ... number of vertices in V direction (veritical in matrix)
#   dataList ... list of float/double data parsed from text file
def loadTextData(filename):
    ...

Coordinates will be loaded in after calling loadTextData

The 2nd aux-method is to make series of faces line by line. (This method is from Blender addon: add extra objects -> 'createFaces' method. Inferred from author declarations in scripts there, it might be written by Pontiac. If I made a mistake here, please tell me.) We have obtained coordinates of vertices. To make vertices, just append the tuple (x,y,z) to the variable verts. To get faces, containing the list of indices of faces, this aux-method is really helpful.

# Link two lines of vertices
# Returns the list of the new faces
#   verts1 ... 1st Line.
#   verts2 ... 2nd Line.
#   loop ... Link the final with the start.
#   flip ... Flip the normal side of faces.
def makeFaces(verts1, verts2, loop=False, flip=False):
    ...

After we get verts and faces, we can call create_mesh_and_object to create the target mesh. edges is not necessary. (This method is from Blender addon: add extra objects -> 'create_mesh_object' method. Inferred from author declarations in scripts there, it might be written by Pontiac. If I made a mistake here, please tell me.)

def create_mesh_and_object(context, verts, edges, faces, name):
    mesh = bpy.data.meshes.new(name)
    mesh.from_pydata(verts, edges, faces)
    mesh.update()

    from bpy_extras import object_utils
    return object_utils.object_data_add(context, mesh, operator=None)

Once we created this mesh, work finished!

Thanks

"makeFaces" method and "create_mesh_and_object" method are from Blender addon add extra objects. Thank Pontiac.

If you are still not satisfied, please go to the source scripts.

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