Blender basics III: Advanced Modelling - Loop Subdivision

In this chapter I will explain what is a loop subdivision, how to apply it to a mesh (dividing / splitting the mesh), and how to select and move these edge rings.

Loop Subdivision (Edge Rings)

What is a loop subdivision? A loop subdivision is a group of edges that splits the whole mesh in two parts; it must split a whole group of ortogonal edges, otherwise it would be a simple edge division.

Figure 1: Mesh split by X, Y and Z axis

A loop subdivision can be created by pressing 'R' key while holding 'Control' (that is, Ctrl+R). Once pressed the hotkey, a magenta line will appear in the model as a preview of where the edge ring will be created (see Figure 1). By moving the mouse through the mesh, we can see the different edge rings that can be created, accepting the desired one by pressing the left mouse button.

Then the edge ring preview will be fixed in the selected section, but we can move the edge ring preview within the enabled section (see Figure 2, move along red arrows), which allows us to split the mesh not only by the middle section but in an asymetric-like mode.

Figure 2: Fit the ring to the desired position

Once placed in the desired position, we can proceed with the loop subdivision by accepting with left mouse button. We can also create the edge ring in the middle position, by accepting with the middle mouse button instead.

So the process is:

• Press Ctrl+R
• Move mouse to select the section to apply the loop subdivision (fig.1)
• Press left mouse button *
• Move mouse to fit the final position of the edge ring (fig.2)
• Press left mouse button *

(*) By pressing the middle button the mesh will be divided by the middle point bypassing the last option of fitting the exact position.

And now what?

By using loop subdivision we can easily divide our meshes (most when working with symmetrical meshes, but also with asymmetric ones). But we can also select the whole ring with a single click when we later work with the mesh, by pressing the right mouse button while holding pressed the 'Alt' key (Alt + Right Click).

Figure 3: Edge ring selection

This selection method allows us to select all the edges/faces/points of the loop subdivision with a single click, and thus allows us work much quicker with symmetrical meshes, but also helps to work quicker with any kind of mesh.

Multiple Subdivisions

If you want to create more than one ring at a time, it's possible by moving the mouse scroll wheel up/down just after pressing Ctrl+R (step 1). That will increase/decrease the number of simultaneous subdivisions to apply, and will be displayed in the preview.

Figure 4: Multiple mesh subdivision

So loop subdivision is an easy, quick and very helpful tip that will allow us to work in a quicker and easier way with Blender. This is one of the many techniques that makes Blender much easier to use than we ever thought before. Happy blending!