How to make a circular cut? I'm trying to add basic materials to a low-poly model, and was curious if there was any way to cut in edges in a circle from a single point, so I could apply materials to faces like seen in my reference image to the right. I could go through with the knife and make cuts by hand, but that seems tricky and time consuming for likely sloppy results. Any tips on how to achieve the texture pictured would be greatly appreciated.

The OP wrote in a comment:

I'm looking for a way to add edges without changing the mesh, just so I can apply materials to faces to color.
Mesh LoopTools Click Circle

Mesh Loop Tools or Loops Tools is an Addon which must be installed in User Preferences.  That takes 88 seconds or less. 

Know that the faces of a mesh can be UV unwrapped and assigned a texture and painted. 

Simplified form mesh. Clearly the more low poly your mesh,  the more the hole will look like a polygon or octagon .. rather than a smooth circle with high vertex density.



Stages of editing left to right top to bottom.  Edit Mode.


Yellow vertex dense cylinder
Blue Partial quad strip extrusion
Yellow Loop Cuts for local vertex density
Blue Two Patches cut out in square on both sides.  Bridge Edge Loops





Yellow Mesh Loop Tool click Circle changes rectangle hole to circular hole. Select the vertices in edit more beforehand. See Side Panel. This is the step most relevant to the OP





Blue Proportional Editing for edge protrusion
Please improve this to suit you needs
Technique only. No artistry focus.