毫无疑问，Operator是Blender中最核心的一个对象，而且里面保罗万象（不仅可以操作几何对象，所有的菜单都可以控制， 因为blender其实是一个三维图形的超级命令解释器嘛！）。
我们先定义一个简单的Operator。把下面的代码复制到文本编辑中，点击“执行脚本”。
import bpy
class SimpleOperator(bpy.types.Operator):
bl_idname = "object.simple_operator"
bl_label = "Tool Name"
def execute(self, context):
print("Hello World")
return {'FINISHED'}
bpy.utils.register_class(SimpleOperator)
在三维视窗中，鼠标点击，按下空格键输入“tool”，将会列出这个“Tool Name”的Operator工具。
继续，选中“Tool Name”项，并没有出现上面的execute中定义的“Hello World”，怎么回事！？
因为Blender把输出信息定义到标准输出了，如果从控制台窗口启动，将从控制台上看到输出的信息。Blender并没有把信息输出到信息窗口和python控制台， 这是一个让图形界面使用者有点困惑的地方，先按下不表，后面再想办法解决。
现在，换一种方式来定义Operator：
import bpy
class BaseOperator:
def execute(self, context):
print("Hello World BaseClass")
return {'FINISHED'}
class SimpleOperator(bpy.types.Operator, BaseOperator):
bl_idname = "object.simple_operator"
bl_label = "Tool Name"
bpy.utils.register_class(SimpleOperator)
这里用到了python类的继承特性。这是官方文档的例子，但我觉得更符合对象的定义应该是：
import bpy
class BaseOperator:
bl_idname = "object.simple_operator"
bl_label = "Tool subclass."
class SimpleOperator(BaseOperator,bpy.types.Operator):
def execute(self, context):
print("Hello World，i am subclass.")
return {'FINISHED'}
bpy.utils.register_class(SimpleOperator)
酸菜萝卜，各有所爱。一种是行为优先，符合脚本化思路;第二种是标识优先，符合OO的习惯。测试了下，两种方法倒是都能运行。
上面直接把Operator的执行类注册到系统了，下面采用更通用的做法：
import bpy
class SimpleOperator(bpy.types.Operator):
""" See example above """
def register():
bpy.utils.register_class(SimpleOperator)
def unregister():
bpy.utils.unregister_class(SimpleOperator)
if __name__ == "__main__":
register()
一个更综合一点的例子：
# Create new property group with a sub property
# bpy.data.materials[0].my_custom_props.sub_group.my_float
import bpy
class MyMaterialSubProps(bpy.types.PropertyGroup):
my_float = bpy.props.FloatProperty()
class MyMaterialGroupProps(bpy.types.PropertyGroup):
sub_group = bpy.props.PointerProperty(type=MyMaterialSubProps)
def register():
bpy.utils.register_class(MyMaterialSubProps)
bpy.utils.register_class(MyMaterialGroupProps)
bpy.types.Material.my_custom_props = bpy.props.PointerProperty(type=MyMaterialGroupProps)
def unregister():
del bpy.types.Material.my_custom_props
bpy.utils.unregister_class(MyMaterialGroupProps)
bpy.utils.unregister_class(MyMaterialSubProps)
if __name__ == "__main__":
register()
因为“一切皆对象”，Python脚本还可以创建动态类型。如下：
# add a new property to an existing type
bpy.types.Object.my_float = bpy.props.FloatProperty()
# remove
del bpy.types.Object.my_float
对类对象同样适用：
class MyPropGroup(bpy.types.PropertyGroup):
pass
MyPropGroup.my_float = bpy.props.FloatProperty()
＃等价于下面的语法:
class MyPropGroup(bpy.types.PropertyGroup):
my_float = bpy.props.FloatProperty()
动态定义的对象：
for i in range(10):
idname = "object.operator_%d" % i
def func(self, context):
print("Hello World", self.bl_idname)
return {'FINISHED'}
opclass = type("DynOp%d" % i,(bpy.types.Operator, ),
{"bl_idname": idname, "bl_label": "Test", "execute": func},
)
bpy.utils.register_class(opclass)
有点头大，不多解释了。运行下看：
>>> bpy.ops.object.operator_1()
Hello World OBJECT_OT_operator_1
{'FINISHED'}
>>> bpy.ops.object.operator_2()
Hello World OBJECT_OT_operator_2
{'FINISHED'}
现在，我们创建一个操作几何对象的Addon:
import bpy
bl_info = {
"name": "Move X Axis",
"category": "Object",
}
class ObjectMoveX(bpy.types.Operator):
"""My Object Moving Script"""
# blender will use this as a tooltip for menu items and buttons.
bl_idname = "object.move_x" #unique identifier for buttons and menu items to reference.
bl_label = "Move X by One" # display name in the interface.
bl_options = {'REGISTER', 'UNDO'} # enable undo for the operator.
# execute() is called by blender when running the operator.
def execute(self, context): # The original script
scene = context.scene
for obj in scene.objects:
obj.location.x += 1.0
return {'FINISHED'} #this lets blender know the operator finished successfully.
def register():
bpy.utils.register_class(ObjectMoveX)
def unregister():
bpy.utils.unregister_class(ObjectMoveX)
# This allows you to run the script directly from blenders text editor
# to test the addon without having to install it.
if __name__ == "__main__":
register()
一个扩展了菜单和快捷键映射的例子：
bl_info = {
"name": "Cursor Array",
"category": "Object",}
import bpy
class ObjectCursorArray(bpy.types.Operator):
"""Object Cursor Array"""
bl_idname = "object.cursor_array"
bl_label = "Cursor Array"
bl_options = {'REGISTER', 'UNDO'}
total = bpy.props.IntProperty(name="Steps", default=2, min=1, max=100)
def execute(self, context):
scene = context.scene
cursor = scene.cursor_location
obj = scene.objects.active
for i in range(self.total):
obj_new = obj.copy()
scene.objects.link(obj_new)
factor = i / self.total
obj_new.location = (obj.location * factor) + (cursor * (1.0 - factor))
return {'FINISHED'}
def menu_func(self, context):
self.layout.operator(ObjectCursorArray.bl_idname)
# store keymaps here to access after registration
addon_keymaps = []
def register():
bpy.utils.register_class(ObjectCursorArray)
bpy.types.VIEW3D_MT_object.append(menu_func)
# handle the keymap
wm = bpy.context.window_manager
# Note that in background mode (no GUI available),
# keyconfigs are not available either, so we have to check this
# to avoid nasty errors in background case.
kc = wm.keyconfigs.addon
if kc:
km = wm.keyconfigs.addon.keymaps.new(name='Object Mode', space_type='EMPTY')
kmi = km.keymap_items.new(ObjectCursorArray.bl_idname, 'SPACE', 'PRESS',
ctrl=True, shift=True)
kmi.properties.total = 4
addon_keymaps.append((km, kmi))
def unregister():
# Note: when unregistering, it's usually good practice to do it in reverse order you registered.
# Can avoid strange issues like keymap still referring to operators already unregistered...
# handle the keymap
for km, kmi in addon_keymaps:
km.keymap_items.remove(kmi)
addon_keymaps.clear()
bpy.utils.unregister_class(ObjectCursorArray)
bpy.types.VIEW3D_MT_object.remove(menu_func)
if __name__ == "__main__":
register()
复制到文本框，点击“运行脚本”运行下看：
运行这个菜单项，结果如下：
当选中以后，可以选择一次创建多个Cube对象。
注意：直接运行这个脚本，将会导致菜单项多次加载。但是放到Addon就没有这个问题了。