====== Blender Data Stucture ======

  * {{http://ivan/blenderapi/contents.html|Blender API, Local Copy}}


====== Top Level ======

^bpy.context|Context Access\\ e.g., bpy.context.current_object\\ {{http://ivan/blenderapi/bpy.context.html|API Docs}}|
^bpy.data|Data Access\\ e.g., bpy.data.objects["Cube"]\\ {{http://ivan/blenderapi/bpy.data.html|API Docs}}|
^bpy.ops|Operators\\ e.g., bpy.ops.object.add(<parameters>)\\ {{http://ivan/blenderapi/bpy.ops.object.html|API Docs}}|

===== Data Access =====

==== Object ====

=== To get an existing object: ===

  * ''ob = bpy.data.object["Cube"]''
  * ''ob = bpy.data.object.get("Cube")'' # If not found, returns None gracefully
  * ''for ob in bpy.data.objects'' # returns all of the objects iterable

=== To create a new object: ===

  * Create a datablock with ''datablock = bpy.data.lamps.new'' (or ''bpy.data.objects.new'')
  * Create an object, linking datablock to it
  * Can also use operators to create a new object, e.g., bpy.ops.object.add

//From docs, example is to create a lamp//

<code python>
import bpy
from mathutils import Matrix

scene = bpy.context.scene

# Create new lamp datablock
lamp_data = bpy.data.lamps.new(name="New Lamp", type='POINT')

# Create new object with our lamp datablock
lamp_object = bpy.data.objects.new(name="New Lamp", object_data=lamp_data)

# Link lamp object to the scene so it'll appear in this scene
scene.objects.link(lamp_object)

# Place lamp to a specified location
lamp_object.location = (5.0, 5.0, 5.0)

# And finally select it make active
lamp_object.select = True
scene.objects.active = lamp_object
</code>

=== Vertex Groups ===

<code python>
for vertexGroup in ob.vertex.groups:
  print vertexGroup.name
</code>



After establishing a group, you can add vertices to it:

<code python>
verts = ((x,y,z), (x+w, y,z), (x+w,y,z+h), (x,y,z+h), \
    (x,y+t,z), (x+w,y+t,z), (x+w,y+t,z+h), (x,y+t,z+h))
faces = ((0,1,2,3), (5,4,7,6), (5,6,2,1), (6,7,3,2), (7,4,0,3), (4,5,1,0))
me = ob.data
me.name = name+'Mesh'
 
# Create mesh from given verts, faces.
me.from_pydata(verts, [], faces)
# Update mesh with new data
me.update()    
    
vg = ob.vertex_groups.new("Card Face")
vg.add([0,1,2,3],1,"ADD")
# The indexes 0,1,2,3 are referring to the vertices 
# in the order they are added to the object
</code>

==== Polygons ====

Brief example

<code python>
for p in ob.data.polygons:
  p.material_index = ms_index
</code>


==== Material ====

Materials are established separate from Objects, then links are made from Objects to Materials.

=== To get an existing material: ===

  * ''mat = bpy.data.materials["Material"]''
  * ''mat= bpy.data.materials.get("Material")'' # If not found, returns None gracefully

=== To create a new material: ===

<code python>
mat = bpy.data.materials.new(name="Card Paper")
</code>

Assign material to an object **ob**

<code python>
if not(ob.data.materials.get(mat.name)):
  ob.data.materials.append(mat)
  
  # this example adds material to all polygons in ob
  ms_index = ob.material_slots.find("Card Paper")
  for p in ob.data.polygons:
    p.material_index = ms_index
</code>