Assalamualaikum. My name is Widhi Muttaqien from expose academy.
A lot of my students have trouble applying bevel modifier to their 3D models. When I checked their files mostly all of them have the same problems. But before we get into that, some of you may not be familiar with bevel and what bevel modifier can actually do. Okay, so what is “bevel” in Blender’s term? To make things simple, bevel is a process of splicing an edge into multiple edges. If this is done on corner, it will make the corner more blunt or obtuse. There are 2 scenarios why we want to add bevels to our model. First to shape our model in the modeling process. And second to add final details on corners before we do rendering.
For the first scenario you really don’t want to use bevel modifier. Instead, you should use the bevel modeling command. Just to show you how it is done real quickly. Lets select this default cube here and then press tab to go to edit mode. Next, go to edge mode and then select this edge. To bevel this edge we can press control B. And then we can move our mouse closer or further to define the width of the bevel. We can also scroll our mouse wheel to determine the amount of segments which also resulting smooth curve on the beveled area. Click to confirm. If you forget the shortcut you can go to mesh menu, edge and then you can find the bevel command in here along with it’s default shortcut which is control B. Again, using bevel command like this is great for modeling process. But not that great if you want to add subtle bevel on all of the corners of our 3d model. Which bring us to the second scenario.
The second scenario is we want to add bevel effects to all sharp corners in our model automatically. For this purpose, then bevel modifier is the best option. And, beside the benefit of adding bevel automatically, it also has the benefit of non destructive workflow. Meaning we can turn it off or on later as we needed. Okay, now you might be wondering, why the heck I need to add bevels to all of the corners on my 3D model? Well, the answer is, to add more realism to our rendering. In the real world, you almost never see object with perfect sharp corners unless it is deliberately designed like that, such as kitchen knife or sword. Most objects in the real world has blunt corners. That is why if you render your model with it’s original sharp corners they will look somehow wrong. It will not look like a solid object, but it looks more like something made from paper craft.
Okay so to add bevel modifier is pretty straight forward. You select and object. Go to modifier panel in the properties editor. Click the “add modifier” button, then choose “bevel” in here. And we can see Blender add this bevels in all of the edges in our model. Let me turn on the “wire” and the “draw all edges” options in here so we can see the edges more clearly. Okay. The width in here controls the width of the bevel. And the segments in here control how much edge splices on the beveled area which essentially also control how smooth the curve produced by the bevel. Now you can test and experiment with all of these settings your self. But there are two parameters I want to mention in this tutorial. The “limit method” in here and the “clamp overlap” in here. We will discuss the “clamp overlap” later, for now lets take a look at this “limit method” in here. If this is set to none, which is the default. Blender will bevel all of edges in the model, which in most cases not exactly what we need. If we only want to bevel edges that form an angle at certain threshold then you can click on this “angle” option in here. Then we can increase this value. At certain value we can see the bevels in these edges are gone. This is because, the faces between these edges form angles above this value. While these edges form angles below this value.
Okay. So lets go back to our initial question. Why is my bevel modifier not working? Based on my experience, mostly the bevel modifier not working because of 2 consecutive reasons. First it is because the 3D model has double vertices. And, second it is because by default the bevel modifier has the “clamp overlap” option turned on. In here I have a model from one of my students at Udemy. We can see if we add bevel modifier nothing happens. Even if we increase or decrease this width value, nothing happens also. Okay, the first reason is because there are double vertices in the model. If we turn off this bevel modifier first, then go to edit mode and go to face mode. In face mode, all of the points we see in the view are the center of faces. Notice in here we have center of faces at edges. This is not normal. If we go to vertex mode and drag one of these vertices. We can see we actually have double vertices in here. Okay let me undo this, and go back to object mode. Okay.
We can force bevel modifier to bevel the edges even though there are double vertices in our model by turning off this “clamp overlap” option in here. Let me turn this modifier back on. Basically this option, if it is on, will prevent the modifier to produce bevel effect if the result will look bad because they will overlap. The overlapping happens because the existing gaps between edges are too small. Notice if we have this option turned off. And let’s put smaller width value like 2 mm. At the glance the model looks okay. But once we get close to this area, we can see this ugly result. So now we know why this option is turn on by default. It is to avoid us from having these ugly topology result. So essentially turning off this option is doable but it is not the best solution.
The best and clean solution to have the bevel modifier working, is to first fix the double vertices. So lets turn off the modifier first. Go to edit mode. And lets focus on this area. Before we learn how to fix this, we need to know why are these things happen at the first place? By knowing the reason, we can prevent this from happening again in the future. Okay, so usually these things happen because we do extrude but then cancel it. For example, if I select this face, then press E for extrude then right click to cancel. What we cancel is actually only the movement of the face. Not the face creation. Notice we have these unwanted faces around here. If we drag this face like this, we can see the actual structure of these double vertices in this area. So essentially, if you do extrude, and then cancel it by right clicking. You should press control Z once to go back to the original geometry.
Okay, now what if we already have double vertices like these up here. We can not just undo them because they already gone from the history list. To fix this, we can use the “remove doubles” command. To do that select all by pressing A, then in the tool shelf we can find “remove doubles” in here. Just click on it. Now as we can see, Blender fix all of the double vertices for us. And so, if we go back to object mode and turn on the bevel modifier again. Our model will be beveled as expected. Without any broken topology even if we turn off the “clamp overlap” option in here.
Okay guys. So that is how we can fix bevel modifier in Blender. If you want to learn Blender from scratch, and master all of the in-depth 3D skills, in the shortest time possible. Then you should join my Udemy course “Blender 3D from zero to hero”. The link is in the description below. And as always, subscribe to my channel, share the video. Give a thumbs up if you like the video, and give a thumbs down if you hate the video. Check out my other tutorials. Wassalamualaikum.