Extruding

In this section, we will learn about an essential part of building a mesh by extruding different selections.

Extruding a Plane

Open a new Blender File and delete the default cube.

Add a plane and enter  Edit Mode.

Use  Edge Selection Mode and select one of the edges. Press E to extrude the current selection. By pressing one of the axes, we can extrude along that axis. Notice in the top left corner how the extrusion distance is shown.

Use the LMB to confirm the extrusion.

If you go into orthographic view, it can be difficult to see your extrusion. By changing your selection mode to Vertex, it will be easier to see thanks to the highlighted vertices.

Extruding on a Cube

Remove the plane and add a cube (use Shift + C to recenter the 3D Cursor) with three subdivisions the same way we did previously W > Subdivide.

Create a selection of faces and use E to extrude the selection. We can continue extruding on our new geometry as well to build the model.

Inset

Using the Inset tool by pressing I creates new faces that by default slide towards the center of the selection. By moving the cursor, we can adjust the amount of inset.

By holding Ctrl during the Inset operation, we can adjust the depth. This can be inward and outward of the cube. While doing this operation, take a look in the bottom left corner; there are different parameters/functions that can be activated by using those shortcuts. Try them out! By using I during the inset, we can inset the individual faces.

Extrude Menu

Using Alt + E will open the extrude menu listing multiple ways of extruding the mesh. The only other option we will go over is the Extrude Manifold that allows more freedom when extruding. A few things to consider are:

• Extrude Manifold automatically connects to faces (possibly creating N-gons).
• Extrude Manifold stops working effectively when the next loop is encountered.

Experiment with the other options.

Extrude Vertices

In this example, we can go to the top view and start extruding a silhouette. Extruding can be done quickly by holding Ctrl + LMB at the location where you want the extrusion to go. This also works for edges and faces. We will learn how to fill and connect meshes in a later lesson.

Common obstacles and solutions

This section tries to offer solutions to some common obstacles that you might encounter during these operations.

If you want to cancel (Esc or RMB) the extrude operation, it is better to Undo using Ctrl + Z to avoid overlapping mesh elements.

Avoid extruding inward where faces are perpendicular, creating overlapping faces. Try to add "thickness" to your model by using the Inset operation.

Unless you want to separate the extrusion, it's not recommended to extrude edges out of solid shapes.

In general, when you see "Z fighting" or jittery faces like this, there is usually something wrong with your mesh. Make sure not to overshoot your inset; it is the same for any operation that causes these errors.

Be careful when extruding neighboring faces that create a very thin connection. There are multiple solutions, but using an Inset works fine.

Mini assignment

Use extruding and inset operations starting with a subdivided cube, scroll down to see the solution (tip: it can be done with inset only).

Solution

That was the end of the lesson. We have learned:

• How extruding works on vertices, edges, and faces.
• How to recognise issues with your mesh and how to solve them.