When we model hard-surface objects in blender, nearly every object has at least one bevel, some have many bevels and others have many different bevels. So it looks like we had better learn how to bevel properly.
Let’s start with terminology. In the world of CAD (Computer Aided Drafting) and woodwork, rounded corners are called fillets, while a flat edge across a two edges is called a chamfer:
Things are a little different in Blender because a mesh cannot have a geometrically perfect curve like a 2D fillet – instead a curved surface is made up of lots of flat faces. The more faces, the rounder the edge looks. Because of this, a different term is used – a Bevel. You can have a single-faced bevel (equivalent to a chamfer) or a multifaceted bevel, but it’s still a bevel:
Creating a Destructive Bevel
The easiest way to create a Bevel is to use the bevel command . This method, once executed, cannot be easily changed and is therefore called a destructive bevel. ( See Destructive vs Non-Destructive explanation) .
Let’s start with a simple object – a cube:
Switch to Edit mode and select the lower right edge:
Now we use the bevel command . A dotted line connects the middle of the selected edge to the mouse cursor. Move the mouse and a bevel starts to be created dynamically. When it looks approximately the correct size, [Left Click]. A collapsed Parameter panel appears :
Click the arrow and the whole panel expands. For the purposes of our example, change the Width to 0.4m and Segments to 1. The panel should look like this:
Now let’s look at a bevel made of just 3 sides. Select the top right edge:
In the same way as before we use the bevel command . A dotted line connects the middle of the selected edge to the mouse cursor. It doesn’t matter whether the correct number of bevel segments are being displayed, just get the size roughly correct. In the Bevel, parameter panel set the Width to 0.4m again and set the Segments to 3. The panel should look like this:
In just the same way we use the bevel command again after this time selecting the left hand upper edge. In the Bevel parameter panel set the Width to 0.4m again and set the Segments to 10. The resulting bevel should look like this:
A Matcap for Better Viewing
Now we’ll look at our beveled cube with solid viewport shading
To make the beveled faces really stand out, instead of the Studio “clay model” view, we’ll set a MatCap lighting method of shading. We will use a red glossy metallic style. This lighting style is just for the appearance of the object in the viewport, it is not an actual material attached to the cube. We use this particular MatCap to help show up any imperfections in the surface of our model. Click the Drop-down arrow, select the MatCap tab, and choose the Metal Car Paint ball:
Compare this 3D image to the first two images in this article. How can we make our multi-faceted bevels look like beautiful clean curves?
In Blender, we have a weapon that the CAD boys don’t have. We can fake a curve by manipulating the direction of the reflected light where the faces meet. This is a complex subject of manipulating Normals:
Each face has a normal which is perpendicular to the surface like a thumbtack with the head representing the face. Face normals are represented by the cyan lines in the picture above. In addition to surfaces, each vertex has both Vertex Normals and Split Normals (represented by the purple lines). The process of faking a curve is called smoothing and the subject can get quite complex. As a very simple explanation, the act of smoothing is a process where the normals are changed to tell the renderer that a sharp edge or point which reflects light in a certain way must instead reflect light differently. It’s a complex subject and if you’d like to know more I recommend watching this video created by CG Masters.
How to wave a magic wand and smooth our bevels
It’s a simple process. Switch to Object mode and select the object to be smoothed.
Click the Object Data Properties tab in Properties panel and under the Normals drop-down enable Auto Smooth by clicking the checkbox and set the angle at which, all edges below that angle will be smoothed:
The [right-click] in the viewport and select Shade Smooth
Notice how the smoothing of the Bevel faces appear to be equally good, but you can see the difference between the 10-segment bevel and the 3-segment Bevel on the edge. Notice also that the single flat bevel is not smoothed because we have set our Auto Smooth to 30 degrees and this bevel’s edges are 45 degrees, so they are unaffected by the smoothing:
So why don’t we just increase the Auto smooth angle? Well, we could, but usually the results are not good because we are trying to make the smoother work too hard. It needs to be helped out with a few more faces to work with. (I told you, modelling was not only precise, but also an art form!). It would be better to bevel the two edges individually.
Bevelling the Sharp Sides
Now it’s time to look at the flat sides. We want to add a bevel all the way around the edge of the sides. We go back into Edit mode with wireframe view and select an edge all the way around. Select one edge and while holding down , click another edge segment in the chain. If selecting the whole ring doesn’t work, change the view slightly and try again. If it still won’t work, select one edge, hold down and click another edge segment on the other side. Then repeat clicking the unselected segment next to the one you started with. If it still doesn’t work, check your model for duplicate vertices. You want to wind up with this:
Bevel it with . A dotted line connects somewhere near the middle of the selected edge to the mouse cursor. Move the mouse until the bevel looks right and change the number of bevel segments to 3. In the Bevel parameter panel set the width to a nice round number that you can remember. For this model I suggest 0.05m The model should look like this:
Do the same for the other edge ring, but just for fun, this time give it 10 segments and a width of 0.2m. Switch back to object mode with solid viewport shading
And your model should look like this:
Notice that the bevel at the bottom in this image looks correct but the top is faceted and unsmoothed. If you recall the top bevel ring only had 3 segments, which means that the 90 degree angle was split into three which means 30 degrees between facets. Our Auto Smooth is only set to 30, so they don’t get smoothed.
To fix this we simply increase the Auto Smooth a little :
And we wind up with:
Continue to Part-2