3D modeling has had several leaps in the past decade or so, new tools and techniques have made the process a lot easier
And quite faster, from 3D sculpting to retopology tools and 3d scanning all those mark great points in the development of 3D modeling in the last couple of years.
In this article I will take you with me to explore the fundamentals and basics of 3D modeling, I will teach you techniques and processes that are used in most 3D software the naming might be a bit different but the end result is always the same, nevertheless, I will use Blender 3D as an example.
The reason why is that Blender is widely used these days and is slowly it’s becoming an industry standard, on top of that anyone reading this can follow along with Blender as its a Free to use software, but don’t worry I will sneak in a bit of Maya naming conventions as well.
So without further or do let’s dive right in.
Basic 3D Concepts
Primitives are objects that you can easily create in any 3D software, those are widely used as the building blocks for any 3D object you will create, they span from a Cube to a Plane to a Sphere and of course Suzanne ( Monkey head in Blender ).
Of course, you can create a 3D object from scratch starting from a single point which is called a Vertex, but usually, all 3d artists start from a primitive of some sort or from a 3D sculpt.
To create a 3D primitive in Blender follow the steps below:
- Shift+A anywhere in the viewport
- Go to meshes
- Then choose one from the list I recommend starting from a cube
Okay we have our cube created and its in the middle of the viewport, to access the elements of this cube and by elements I mean the components that make up this cube in 3D, and those elements are:
- Vertex (single point)
- Edge (Line consisting of 2 points connected)
- Polygon ( surface consisting of 4 points and 5 edges)
- Triangle (surface consisting of 3 points and 3 edges)
- Ngone (surface consisting of more than 4 points and 3 edges)
More about these components can be found in our guide to Low Poly Models.
To edit the cube components press tab and click on “Edit Mode” this mode lets you control this object’s vertices, edges, and polygons.
To get out of edit mode just hit tab again and click “Object Mode”.
Blender 3D Modeling Techniques
One of the most famous commands in 3D modeling is “Extrude” and I think it’s the same name in most software maybe if you use Modeller brush in Zbrush it’s basically the same thing as “Qmesh”.
Let’s explain what extrude is by applying it to the 3D primitive cube that we created.
If you’re not in edit mode, please go into edit mode and then press 3, when you do so you are now in Polygon mode, because 1 is vertex mode
2 is edges mode and 3 is polygon mode.
Select one of the faces of the cube and hit space, and type extrude, a list of commands will show up, we want to select extrude faces.
After clicking on extrude faces move your mouse a bit and you notice what the extrude does.
Extruding is the process of expanding or appending one of the faces of our model in detail it duplicates the face selected and creates 4 new polygons from the side of the extrusions, this allows us to have more geometry and to create interesting shapes as we please example below.
One last note on extruding is that it can be applied not only to faces but also to vertices and edges.
The Bevel operation is widely used on edges, to give that chamfer look and make any edge more interesting and able to catch the light and create interesting visuals in light backing.
Beveling is duplicating an edge with the ability is scale inwards or outwards to best demonstrate this please let’s look at some examples, below is a before image of an edge selected.
We apply the Bevel the same way we did for the extrude, we search for it and then click it, notice below what happened to the edge it got split into 2 edges and expanded in the opposite direction of each other.
Look at the example below where I beveled the edges beveled before, you can clearly see the effect it has.
One note is Bevel works on edges and faces but in some applications, it doesn’t work on vertices but in Blender, it does work on vertices.
Inset is basically extruding but without moving the polygon, what it does is that it creates a new polygon and its surrounding polygons and scales it down or up below you can clearly see the effect of inset.
Combined with extruding you can create some interesting shapes with inset like the example below.
Starting from a primitive is a great way to start your 3D model but sometimes you don’t have enough edges or vertices or faces starting out, so you need to create new geometry without the need to Extrude Inset or Bevel.
A loop is an edge that goes all along a mesh you can imagine it as you are drawing a line starting from a point and returning to it.
In Blender this action is called loop cut you can access it from the left side menu or you can, of course, use the space bar to search for it.
Once you hover over the mesh you will notice a yellow line appears telling where that new edge loop will be at this point nothing is created yet once you click and drag you can now position where you want your loop to be exactly it doesn’t have to be in the center of course.
As soon as you release clicking the mouse now your loop is created below is the image of the new loop.
Edge Loops vs Edge Rings
It’s very important to identify the difference between loops and rings, a loop is a continuous selection of edges the edges are attached to each other with vertices.
An edge ring is a selection of edges that are parallel to each other and not connected check out this image below that shows the difference between an edge loop and an edge ring.
Knife Tool (Cut Tool)
A very important tool in every 3D modeler’s toolbox is the knife tool, in some applications, it’s called the cut tool different naming but does the exact same thing.
The knife tool is used as the name suggests to cut throughout the 3D mesh, when I say cut I don’t mean having 2 separate 3D meshes, no.
What I mean is creating new edges where to want to add, remember adding a loop creates a loop line of edges across our mesh, but if we only wanted to create one single edge for example what if we want to turn a polygon to a triangle but adding an edge across it, that cannot be achieved using loops.
You can find the knife tool in Blender easily you can the drill from previous exercises by now. Once selected you will actually see a knife cursor appears, go ahead and click from one point to the other it will create a purple line where the new edge will be created.
Beware that where ever you keep pressing new edges will be created, and the only way to end the cuts you did is to press Enter on the keyboard, only then the new edge will be created, if you click escape while doing the cuts it will cancel them.
Check out the image below where we created a new edge inside a polygon and the result is 2 triangles.
Merging is the process of taking 2 vertices and combining them into 1 vertex, this is essential in any 3D model you will build, whether you want to make a model symmetrical by deleting one half and mirroring the other half and then merging the points together to make one mesh or simply reducing the poly count of an object by merging duplicate vertices.
Let’s take the example below where we want to combine the top 2 vertices together, let’s start by selecting the 2 vertices that we want to merge.
After selecting them press the space bar and click on “Merge at Center”, what this does is merges the 2 vertices at the center point of the distance that separates them from each other, of course, you realised that there are other Merge operations feel free to experiment with them (that’s how we learned in the old days).
Not very often used but when needed it’s the only tool that does the jobs very fast.
As the name suggests this tool bridges between 2 edges and creates a polygon in between, be careful in order for the bridge command to work properly there should be an equal amount of edges on both sides, this means you can bridge 1 edge with 3 edges, it has to be 3 to 3.
Let’s look at the example below, select the 2 edges you want to bridge, search for the command using the space bar and click it.
See the example below of how the bridge tool actually worked and connect 2 edges together.
Sliding an edge is very useful when you are trying to tweak a 3D mesh and create a proper topology for your mesh. Edge sliding is the process of moving your edge along the mesh surface, this will not modify your mesh visual look this will only alter the edge location.
This process can be very useful if your working with subdivisions and smooth 3D meshes, as the closer 2 edges are to each other the sharper the effect is, check out the image below for yourself one with 1 edge and one with 2 edges closer to each other.
Separating a mesh that has parts that are not connected to each other is something you will encounter and would want to apply to your mesh in your 3D modeling journey, check out the image below we have this cube that is made of 2 parts, it’s still one object but clearly, it’s still combined into 1 3D mesh.
To Separate the mesh go to face mode and press “A” on the keyboard, that will select all the faces then search for the command “Separate by Loose Parts” and click on it.
Immediately the object is now split into 2 separate objects, if you go to object mode using the tab key you will see that indeed now there are 2 objects, Image below.
Just like we have a separate command, we also have a Join one, and this does the exact opposite, it combines 2 separate objects and makes them 1 single object, and this is very useful if you have a character and you mirrored one Half and then you want to Join those 2 halves into 1.
The Difference with this tool is that we start from object mode as we have 2 separate objects, then select one and shift select the other one, then search for the join command using the space bar and press it, and there you have it.
Holes are areas of your mesh where there are no polygons and these are always to be avoided unless you’re working in the games industry and those areas are not shown to camera then it’s part of optimization to delete those polygons.
Anyways check out this image below, clearly, we have a hole in our mesh, and in order to fill that hole with a polygon, the process is very simple:
- Double-click on one edge of the hole, this will select the loop
- Space bar and search for Fill
- Click on Grid Fill (if you want to fill with polygons only and not triangles)
And that’s it check out the result below how the hole that was in our cube is now filled with a polygon. The other Fill command may result in non-quad results but I find grid fill does the job most of the time.
Normals in 3D Modeling
You can’t talk about 3D modeling and not mention Normals! Because at one point you will face issues with normals there is no hiding from this fact so I thought it better to include a small chunk about it in this article.
Every Face (polygon) in 3D has 2 sides, one facing the camera and the other facing backward, a normal is the direction of a certain polygon is it facing us or flipped, a polygon that is flipped has a flipped normals towards the inside meaning the side that renders correctly is not facing us and this results in a hidden or unwanted visual results. Below is a preview of Normals for every face.
A polygon that has its normals flipped doesn’t smooth correctly in a subdivision workflow and is hidden in game engines, so it’s very critical that we pay attention to our models before we export them and make sure that all of our normals are facing us correctly.
Some commands that are related to normals are:
- Flip normals (this flips the normals of the selected face or a whole object with all its faces)
- Set normals to face (this resets all of the normals and sets them to each individual face of your mesh)
So in a nutshell whenever you encounter an issue with your mesh and you’re not sure what’s happening always make sure to double-check the normals as it might just be the culprit.
3D modeling is a very exciting journey, and I say journey because it’s not a point for you to reach and finish, it’s continuous learning through trial and error, through trying new techniques, new scripts, and new tools.
If its hard at first, it’s fine that’s how its suppose to be that means you’re doing the right thing and practicing outside your comfort zone you will get better with each 3D model you will do whether it looks great or not every model is a learning experience, I get asked a lot how to become a good 3D modeler, and the answer is simple, “Master the basics and keep practicing”