Now, let's make a few changes to the robot model. Select the upper part of the leg and add a few subdivisions. This process is identical to the one used in the first two projects, where we added a circular hole to a 3D mesh. If you don't remember the process, select a face and erase it, and at the same place where the face was, add a mesh circle.
First add a new edge loop to the cube that represents the upper part of the leg, as shown in the following image (section 1). Then, add another set of five edge loops to the model (section 2).
With the edge loops added, select the four center faces of the model and erase the face (section 1). Align the 3D cursor at the center of the hole opened, and add a mesh circle in a view perpendicular to the hole. The circle must have exactly eight vertices (section 2).
When the circle is placed and scaled to fit in the hole, we can fill the space with faces using the Shift+F keys. Or, we can select four vertices at a time and...