Conto using from our previous article on Blender 3D modelling basics, in this article we use subdivisions and loop cuts to make more complex and realistic shapes.
In our previous article we covered how to create basic objects and use subsurfaces to make more complex analogue shapes. But what if you don’t want organic shapes? What if you want something that looks like a machine with hard edges?
If you don’t have Blender 3D, go to www.blender.org and download your free copy now.
Note: Despite appearances, this is an advanced modelling tutorial that gives you essential techniques for making your models look more professional. It’s not a complex model; it’s a cube, but in order to progress onto more advanced shapes, you need to refine your modelling techniques and attention to detail first. If you can make a cube look realistic, then more complex objects will automatically look more real and professional. Enough said.
We talked about subsurfaces last time, but we didn’t really say what they were. The basic shapes you make are a mesh, a 3D object built of a small number of faces. Subsurfaces use those surfaces to build another surface beneath the first, using the original mesh as a control mesh to move and shape the subsurface.
We’ll use them again in this tutorial but in a somewhat different way.
Harden Edges with Loops
The trick with hard surface modelling is to use subdivision surfaces and loop cuts to ramp up the amount of geometry around a corner or edge. Loop cuts add geometry and clustering geometry together at an edge or corner to make the detail more realistic.
Take the basic cube for example. As a default it has sharp clinical edges, but to make it look like a real object and not a computer-generated perfect primitive, you have to have ever-so-slightly rounded edges and corners.
First, add a subsurface modifier to the cube. Click the Modifiers tab (the spanner) and “Add Modifier -> Subsurface.” Ramp the view subdivisions up to 3 and render up to 6. This turns the cube into a ball, as the subdivisions soften the edges of the geometry.
To add loop cuts to the cube to bring back the hard edges, select the cube with the right button and enter edit mode. Now you will see the underlying cube and can add geometry to it with loop cuts.
Click the Loop Cut and Slide button under the tools tab on the left (or use the “Ctrl + R” shortcut), and hover your mouse around the cube. Purple cuts will be displayed as you hover near the edges of the cube. Click the mouse to select one, and now you can slide it back and forth along the plane.
As you slide it back and forth, you will see the subsurfaces moving to show the new geometry. Click the mouse again to cut the polygons at that point.
Place another loop cut in the same surface, and slide it to the opposite edge.
Notice how the geometry is starting to spread out to the edges of the cube.
Add two more loop cuts at the top and bottom. (You will have to hover the mouse around the left and right edges of the face to show them.) Drag them to the edges at a similar distance to the others.
Now go to another face. You have to do another side to make the loop cuts even on all sides of the cube.
Note: it’s hard to get it until you actually do it, but once you have this technique down, you will be able to do this with any shape.
Now render the image using F12 (making sure to set up some lighting etc., so you can see the cube), and you will see how much more realistic this second cube looks compared to the first at the top of the page.
Controlling geometry with subsurfaces and loop cuts is a pro technique for making your objects look realistic and professional. If you have any questions about Blender and modelling, please share them in the comments below.