When modeling in Blender or any other 3D software, you are highly likely to use the loop cut tool. In fact, I can't recall a single modeling session when I did not use it.
The loop cut tool creates a loop of one or more edges along a ring of quad faces. Press Ctrl+R, hover your selected face, scroll the mouse wheel to change the number of cuts and click to confirm. Move your mouse to slide the loops. Left click to confirm the position or right click to center the cuts.
Loop cuts are especially useful for adding additional geometry to your mesh. Continue reading to dive into more information on how the loop cut tool works and for some frequent questions and issues that users face with this tool in Blender.
In the video below I show you a demo and explain how to use loop cuts. You can also find more modeling tools and their explanations here:
Related content: More than 30 Blender modeling tools explained
The full name is loop cut and slide, but we often refer to it as just loop cut. It is a common modeling tool used in Blender for adding more geometry to your object. The tool splits a loop of faces into two or more loops of faces by creating additional rings of edges along the existing faces.
It does not split the geometry; a manifold or watertight mesh remains so even after we use loop cut.
Since the loop cut tool changes the mesh, it is an edit mode only. We cannot manipulate whole objects with it. Nor does it change the geometry. It simply adds geometry to the mesh for later deformation.
A very useful tool that is essential to understand early in your modeling journey.
There are primarily two ways we can use the loop cut and slide tool. Either through the left side tool bar or through the shortcut Ctrl+R. As you get familiarized with it, you will likely use the shortcut key all the time. But we will cover both since beginners may find the tool bar easier.
The reason we will prefer the shortcut is simply because of how much faster it is to use and access.
There are slight differences to how the tool work depending on if you activate it through the tools panel or the shortcut key. Let's start with the toolbar.
You could use the loop cut tool by selecting ‘Loop Cut’ in the toolbar. If you can't see the toolbar press T on your keyboard.
When the tool is selected hover an edge on your object to have the loop cut tool indicate where the cut will go.
In this case, left-clicking your mouse will immediately place the loop cut, and if you want to slide your loop cut you will have to hold the left mouse button down and the cut will be placed on release.
With the shortcut, Ctrl+R, press the shortcut and hover an edge on the object. You clock to make the cut, and then click again to confirm, or right click to have the cut centered, essentially cancel the sliding portion of the tool.
In order to change the number of cuts, use the mouse scroll wheel to adjust how many loops you need.
After creating a loop cut, the operator panel will show up in the bottom left corner, which provides a few different options for your loop cut. From these settings you can adjust the number of cuts, the smoothness, and the factor. The factor represents the position of the cut.
There are also the following additional settings and their uses:
These are all related to the sliding. While we are sliding, we can use the E, F and C shortcuts to change the sliding behavior.
An important limitation to keep in mind when using loop cuts is that they are only able to cut through quad faces. That is faces with four edges and four vertices. The cut will continue straight through all quads until it makes a full circle or encounter a triangle or n-gon. At that point it will stop because there is simply not a single way through the face.
Experiment with these different settings in order to see how they could be useful when deforming your object with the loop cut tool.
To remove a loop cut in Blender, Alt+Click (or Opt+Click on Mac) the loop and press X on the keyboard > ‘Dissolve edges’. When doing this, ensure that you are on Edge select or Vertex select mode.
The shortcut for moving a loop cut is double tapping G. The same as sliding any edge or vertex. Simply select the loop cut with Alt+Click (or Opt+Click on Mac) and double tap G on the keyboard to slide the loop cut with your mouse.
The loop cut tool unfortunately cannot cut through n-gons or triangles, but only through quad faces. Instead, we could use the knife tool to cut through the object. The knife tool can be found in the toolbar, or you can use the shortcut K on the keyboard.
Related content: Blender knife tool tutorial
To loop cut a cone, we can use the bevel tool with ctrl+b followed by the V shortcut key to bevel individual vertices. If we do this to the top vertex, the surrounding geometry will become quads and we can create a loop cut all the way around.
There are a few reasons why your loop cut tool may not be working the way you expect it to. Find common reasons for some questions you might have below.
Keep in mind that the loop cut tool cannot cut through n-gons (faces or polygons with 5 or more sides/vertices) or triangles. If you would like to use the loop cut tool on these kinds of faces, you can use other modeling tools to turn the shapes into a quad, and then create the loop cut.
If your loop cut doesn’t create a full loop, it could be because your edges or vertices are not properly aligned with the adjacent geometry. This could also happen if there is something obscuring the path, eg. a triangle. In these cases, ensure that the geometry of your object is properly connected and there are no obstructions.
We can for instance use the viewport overlays to give us proper cues when geometry doesn't seem to be as it appears.
Related content: How to use 3D viewport overlays in Blender 3D
The loop cut tool can be incredibly useful for adding more geometry and deforming your mesh in Blender. It is also quick and easy to use once you know how as well as the shortcuts.
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