Game Design Smoothing Groups Tutorial Game-Development Milkshape Basics

MilkShape Basics
2) Smoothing Groups Tutorial

A "Smoothing Group" is a very useful tool to make your models look round, without adding any polygons into your model. These groups are a lighting trick, using Gouraud shading, to help make your model look smooth. These groups, when applied correctly, can make your model look very detailed and lit correctly. So, let's get onto how to make these smoothing groups work!

I am going to be working with three 2 stack-8 sliced cylinders for this tutorial to be able to quickly and easily distiguish these cylinders. It is one cylinder, and two smaller cylinders placed just inside the outside edges of the main cylinder.
Okay, so let's take a look at the "Smoothing Groups" tool box inside of the "Groups" tab. The smoothing groups area is circled in red in the image below.

Okay, so let's create our first smoothing group. I will select my center cylinder by clicking it's group name in the Groups tab(in this case it is simply "Cylinder01") and clicking on "Select", or by going to the Model tab and clicking on the Select tool to select it that way. NOTE: When you are creating smoothing groups, and you are selecting the part of the model you wish to smooth with the "Select" tool, make sure you have "Faces" selected in the "Select Options" at the bottom of the Model toolbox. If you select only the vertices of the model, the smoothing groups will not work.

Okay, the center cylinder is selected, it's time to create a smoothing group for it. Go into your Groups tab, and look down underneath the Smoothing Groups header. There are two buttons there, "Select" and "Assign". Click on the "Assign" button if it is not already depressed. We will talk about the "Select" button a little further down. Now, click on the button titled "2".

Have a little look inside of your 3D Viewport and see if you can notice a change!

If everything worked alright on your end, your center cylinder's smooth shading should have changed quite a bit as in the above image. You may be wondering why we assigned this cylinder into the second smoothing group rather than the first. The first smoothing group is designed for the "entire" model, not individual pieces. Smoothing groups 2 through 32 are all for seperate parts of your model. So what exactly does that mean? This means that every "group" of your model that you assign to a smoothing group will have seperate shading than the rest of the model.

Let's prove this point by doing the rest of the model. Deselect the center cylinder (named Cylinder01 in this tutorial), and select the cylinder on the left side (named Cylinder02 in this tutorial). Go into your Groups tab, and under the Smoothing Groups header, click the button called "3".

Your result should be similar to this:

Deselect that cylinder, and select the right cylinder. Assign this to smoothing group "4".

Now, take a look. Your model should look quite similar to the one in the image below:

Compare that to the original model that had no smoothing groups:

You should notice that the model that has smoothing groups has more "definition" and each part is distinguished from the other. A good application of this is a human model with clothes and accesories. You would place the "base" human in one smoothing group, the clothes in a group, and any accesories in seperate groups. This would give a clear distiction between each of the model's parts, making it look more detailed overall!

Now, inside the Smoothing Groups header there is a "Select" button, I said I would explain it, so here you go!
If you have assigned a certain Model group into a Smoothing group, you can select that group with this "Select" button. Let's select our center cylinder with this feature.
Go into your Groups tab, and under the Smoothing Groups header, click the "Select" button. The smoothing group number assigned to the center cylinder was "2", so, with the select button depressed, click on the number "2" button. It should select all of the faces of the center cylinder. Try this with your other smoothing groups.
One last thing....if you want to clear all of your smoothing group information, click on the "Clear All" button at the bottom of your Groups tab. So, there you go, smoothing groups defined.