Tuesday, August 10, 2010

Grid Tutorials Chapter 1 - Modelling Basics - Part 2

It's time for the second part of our Modelling Basics tutorial. Now we're going to jump right in to three dimensional modelling.

Chapter 1 - Modelling Basics
Part 2 - Starting to model in 3D

Modelling in 3D is very dependent on two dimensional objects. In part 1 we've learned about these 2D elements, like vertices, edges, meshes and polygons and the common tools that can be used to manipulate them. Now we're adding another dimension, which is height.

Just like in the previous part, we're going to take a look at the basic three dimensional objects, commonly referred to as primitives.

What can we see in this picture? A cube, a sphere, a cylinder and a pyramid. The donut-shaped object in the top-left corner is called a torus.

The cube has six faces (meshes), each one representing a square.

Now let's start with the first operation, which is extruding a face. We've talked about the extrude operation in part 1 and here it is pretty much the same thing.

If you extrude a face or a group of edges forming a face, it gets translated in the direction you want, while remaining linked to the main body, by creating some new vertices and edges.

The green edges represent the ones which have been extruded, while faces 4 and 5 (including two more on the other side which we cannot see, due to the perspective view) are created when the extrusion is made.

You will find yourself using the bevel tool quite often. If you do not want your model to have too sharp edges (and you don't), you will have to create bevels for each one of the edges, so that it will appear as a smoother edge, rather than a completely sharp one.

Beveling is shown in the picture above. Compare the bevel around face two with the sharp ones around faces 1 and 3.
Usually, in most 3D graphics applications, you will be able to set the level of beveling, which basically increases the number of bevels created for that edge.

Another tool is the polygon subdivide tool (or subsurf). What this tool does is dividing all the faces of your object (or only the selected edges) by creating another, smoother shape.

In the example above you can see what happens when you first subdivide an entire cube (which is represented via the grey lines).

One of the most used tools is the mirror. What the mirror does is it creates a complete double of the selected object and inverts it depending on the chosen axis.
In polygonal modelling, you will usually work with just half of the object, so that you can later mirror it and join the two surfaces together, creating the complete object.

Since we've talked about working with only half of the object, before mirroring it, we should also mention the edge split tool.
What it does is creating another vertex alongside the selected edge, so that you can later use it for different purposes.

Here is the example of using the edge split tool. The yellow edges and vertices represent the ones we have just created using this operation. In this tutorial we've chosen to split the cube right in half.
The picture right next to it represents the result of deleting the right side of the cube, after the edge split is complete. As you can see, these geometrical objects are hollow inside, so by deleting the vertices and edges (also meaning the meshes which they form), we can actually see inside it.

This concludes part 2 of our Modelling Basics tutorial, where we took a look at some of the standard tools used in three dimensional modelling.
In part 3 we will discuss about how curved surfaces are created.

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