Introduction
Knife Circle is a powerful Blender add-on for projecting precise circular cuts onto mesh objects with a real-time preview. It features GPU-accelerated rendering, interactive radius, star and rotation control and orientation-aware cuts. It works in both Object Mode and Edit Mode - in Edit Mode the tool lives under the Knife tool group in the toolbar. Perfect for creating clean geometric cuts with accuracy and speed.
Features
Quick Start
How to use Knife Circle?
- Select one or more mesh objects
- Activate the Circle Knife tool from the toolbar. In Edit Mode it is found under the Knife tool group
- Click to place the circle center
- Move the mouse to adjust radius
- Confirm with Left Click or Cancel with Right Click/ESC
Controls
What inputs does Knife Circle respond to?
| Input | Action | Description |
|---|---|---|
Left Click | Confirm | Execute the knife projection |
Right Click / ESC | Cancel | Exit without changes |
Mouse Move | Adjust Radius | Dynamic radius control |
F | Fixed / Freeform Mode | Switch between fixed/freeform modes |
O | Orientation | Cycle View / Normal / X / Y / Z |
| — Sizing & Shape — | ||
Scroll Up | More Segments | Increase circle smoothness (max 256) |
Scroll Down | Fewer Segments | Decrease segments (min 3) |
T | Triangle | Set to 3 segments for triangle |
S | Square | Set to 4 segments for square |
C | Circle | Set to 32 segments for smooth circle |
V | Segment Input | Type an exact segment count |
P | Star | Toggle star mode |
I | Inner Radius | Drag to set the star inner radius |
R | Rotate | Rotate the shape around its center |
Shift + Mouse Move | Precise Mode | 10x slower radius adjustment |
Ctrl + Mouse Move | Snap Mode | Snap radius to 5-unit increments |
| — Precision — | ||
0-9, Period | Numeric Input | Type exact radius value |
Backspace | Delete Digit | Remove last typed character |
Enter / Numpad Enter | Apply Value | Confirm numeric input |
| — Cut — | ||
X | Cut Through Mode | Switch between surface/through modes |
Interactive Control
Click to set the circle center, then move the mouse to dynamically adjust the radius with real-time preview.
Fixed / Freeform Mode
Toggle between Fixed mode (click to set center, move to adjust radius) and Freeform mode (click and drag to define both center and radius simultaneously) using the F key.
Orientation
Cut on a view-aligned plane or on the global axes.
Press O to cycle the projection plane - View (screen-aligned), Normal (the surface the center was placed on) and the global X, Y and Z axes.
Fixed planes are cut parallel to their normal, so the result is a true circle (or a clean prism through the mesh) no matter how the viewport is rotated. View orientation keeps Blender's perspective projection from the current view.
Star Mode
Create stars with adjustable inner radius.
Press P for star mode and hold I while moving the mouse to set the inner radius. Star shapes start at 5 segments.
Shape Rotation
Rotate the shape around its center before cutting.
Hold R and move the mouse to rotate the shape around its center before confirming.
Quick Shapes
Instantly switch between common shapes with a single keypress - T for Triangle (3 segments), S for Square (4 segments), C for Circle (32 segments).
Adjustable Segments
Modify the number of segments on-the-fly using the mouse scroll wheel.
Numeric Input
Type exact radius values for precise cuts. Start the tool, type a value like 75.5, and press Enter to apply.
Cut Through
Toggle between two modes with the X key - Blue preview cuts only the visible faces, Red preview cuts through the entire mesh. With a fixed orientation, the near-only mode stops the cut at the first surface while through mode sweeps a clean prism across the mesh.
Edit Mode
Knife Circle is available directly in Edit Mode, grouped under the built-in Knife tool in the toolbar. Open the Knife tool group and pick Knife Circle to cut the selected mesh without leaving Edit Mode.
Support
Join our Discord server to stay updated.
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