# Create Circle with Inner Radius

Is there a simple way to create a circle which contains a hole / inner radius. Ideally where I can dynamically set the inner radius when adding (in the same way I can set outer radius when adding a circle mesh).

I can manually create it by adding a circle with no fill, cloning, scaling down, then creating the faces (see attached), but that is tedious and error prone. I could also do it by creating a circle with triangle fan, clone the out edge down, and the delete middle, but again, that is a bit tedious and makes it difficult to get an exact inner radius.

Is there a way to do this natively in Blender, or via an addon?

• From a circle, in edit mode select the vertices, then E+S (to extrude and scale). – lemon Jul 22 at 17:20
• Good answers below, but for the one-off .. Triangle-filled created to radius, all selected, I Inset region with a numerical entry for thickness. X delete center faces? – Robin Betts Jul 22 at 17:33

Quick little addon slapped together using text editor > templates > python > Addon Add Object template.

• Adds two circles, bridges the edge loops.
• If ngon fill is chosen, splits one fill edge, dissolves the rest.

bl_info = {
"name": "New 2D Ring",
"author": "batFINGER",
"version": (1, 0),
"blender": (2, 80, 0),
"location": "View3D > Add > Mesh > New 2D Ring",
"description": "Adds a 2D ring (circle with hole)",
"warning": "",
"wiki_url": "",
}
import bpy
import bmesh

from bpy.props import (
IntProperty,
BoolProperty,
FloatProperty,
)

"""Add a 2D filled ring mesh"""
bl_label = "Add 2D Filled Ring"
bl_options = {'REGISTER', 'UNDO'}

min=0,
default=1.0,
)
min=0,
default=2.0,
)
segments: IntProperty(
name="Segments",
description="Number of Segments",
min=3,
default=8,
)
ngon_fill: BoolProperty(
name="Ngon Fill",
description="Fill with ngon",
)

def draw(self, context):
'''Generic Draw'''
layout = self.layout
# annnotated on this class
for prop in self.__class__.__annotations__.keys():
layout.prop(self, prop)
layout.prop(self, prop)

def execute(self, context):

me = bpy.data.meshes.new("CircleHole")

bm = bmesh.new()

ret = bmesh.ops.bridge_loops(bm, edges=bm.edges)
if self.ngon_fill:
edges = ret['edges']
e = edges.pop()
bmesh.ops.split_edges(bm, edges=[e])
bmesh.ops.dissolve_edges(bm,
edges=edges)
bm.to_mesh(me)
me.update()

from bpy_extras import object_utils

return {'FINISHED'}

def register():

def unregister():

if __name__ == "__main__":
register()

# test call


Though I would add that the functionality is very similar to add cone primitive, with no fill and no height (can scale totally to zero in z and apply)

• This is awesome. I was actually starting to build my own but you beat me to it. Do you plan to release it outside of stackoverflow? Seems like it would be super useful. – mikechambers Jul 22 at 22:52

Maybe its a good subject for the new 2.8 gyzmos!

Create an edge with two vertices corresponding to the inner and outer part of your disk.

Choose the spin tool.

Rotate as you want.

Tune the result with the operator panel.

One way to work around it natively is to create a mesh with only two vertex and an edge connecting them.

Place them strategically like along the X axis so you can control vertex position from the properties panel. Their X coordinate will directly control absolute radius for inner and outer circles quite easily.

Then just add a screw modifier to the mesh. You can control curve resolution and spin angle non-destructively from there.

You can copy this object around instead of adding new ones, for easy duplication