Create a Game Ready Fire Extinguisher with 3D Studio Max: Part 3

Final product image — What You'll Be Creating

In this part of the tutorial, we will learn how to unwrap the low poly fire extinguisher model. UV Mapping is a major part of the video game pipeline, as many different things depend on it. A perfect unwrap is the combination of various tricks and techniques, which we will go over now.

Additional Files

Important Points About Unwrapping

When we talk about creating perfect UVs for an asset, there are a few points which are very important.

1. Keep Everything Inside the UV Box

When you open the UV Editor in 3ds Max, you'll see a box. I have marked it below with a green rectangle. This is called the UV space. We need to place our unwrapped faces inside this box, as anything placed outside of it will cause repetition (or texture tiling).

2. Maximum Use of UV Space

Be sure to fill the UV Space with your UV layout as much as possible. This is the best way to get the most resolution out of a texture for your asset.

3. Overlapping Faces

Try to overlap any parts of a model that have the same UVs in the UV space, because if they look the same, or if you are going to paint the same texture on them, then why waste the UV space! For example, if we were unwrapping a car, we can overlap all four tires because they all look the same and will have the same UV layout.

4. Distribution of Texel/Pixel Density

Most of the time, we keep the distribution of texal/pixel density equal (the particular count of pixels in an area). For an example, say we're unwrapping a gun’s parts, like the barrel, trigger and handle. We should keep the same pixel density for all of these parts, otherwise they will look different, and you'll be able to see that difference in the textures.

This condition can change according to a particular game. These days, most of the FPS (first person shooter) titles keep the nearby parts of a model, double the resolution, as compared to the further away ones. For example, the backside of a gun is the most visible part in a war game, so we need a better texture resolution in this area, compared to hidden parts or parts that are further from the camera.

5. Try to Keep Similar Parts Together

Say you're texturing an asset in Photoshop, and are working on a particular part. If you suddenly need to find the adjacent part, you would go back to 3ds Max, open the UV Editor, and select the required part. This is a very long process, just to get to know the correct position of that part. To avoid this problem, it’s good to keep parts nearby and together when unwrapping.

6. Texture Orientation

Keep the UV orientation (or facing) just like your model. For example, if you flip an unwrapped face or rotate it vertically, then your texture and texture flow will also be flipped or reversed.

7. Keep the Seams Inside or Hidden

It’s a good habit to keep the seams inside your object, so they will be less visible.

8. UV Bleeding/Padding

Keep a small gap between each set of UVs, so that when we compress a texture later, they won't merge together. Most of the time, I keep the padding according to the texture's size. If the size of the texture is 2048x2048 pixels, then I keep a gap of six to eight pixels between each UV island.

UV Mapping Examples

Box & Cylindrical Mapping

Here you can see two objects and their unwrapped UVs. The box is split into six sides and is a bit separated, because each side has a different surface orientation (90 degrees). The sides of the cylinder are a single long UV plane, so there is no sense in splitting them.

Planar Mapping

When you apply the Unwrap UVW modifier to an object, you'll get four different projection options: Plane, Cylinder, Sphere and Box. They project and open the UVs of the selected polygons, according to their names. For example, if you want to unwrap the selected polygon of the box shown below (which is facing the Y axis), you would choose a Planar Map projection and the Y alignment.

Axis Alignment

In this example, the Cylindrical projection looks weird inside the UV box because I didn’t align it according to the right axis.

But as soon as we press the Z alignment option, our UVs looks great!

I hope you now have the basics of unwrapping. Now we'll start unwrapping the fire extinguisher model and you'll learn some more tips and tricks during the process.

1. Initial Unwrapping

Step 1

Let’s open the low res fire extinguisher model, which we saved in the last part of the tutorial. We will now unwrap it step by step.

Step 2

First of all, with the fire extinguisher model selected, go to the Utilities panel and apply Reset XForm.

Step 3

Now right click on the fire extinguisher and convert it to an Editable Poly by going to Convert to: Convert to Editable Poly (or you can collapse from the modifier stack by right clicking on the XForm).

Step 4

Here we need to apply a Checker map to the asset, so we can see if there is any stretching in certain areas. Press M to open the Material Editor, select an empty slot and then click on the Diffuse channel.

Step 5

This opens the Material/Map Browser window. Here choose Bitmap and select the Checker Map file provided, and apply it to the model.

This is the Checker Map.jpg file.

Step 6

Here you can see the checker map applied to the model. Now go to the Modifier list and apply the Unwrap UVW modifier.

Step 7

Here are some options found in the Unwrap UVW modifier. I will explain each of them.

Selection: You can select the UVs by Vertex, Edge or Polygon. There is a white box at the end of this row; this is for Element selection.
Modify Selection: You can grow and contract the selection with the + (plus) and – (minus) buttons. There are icons with one single line, and three lines in a grey color. These will turn green when you select an edge on your asset. These lines help to Loop and Ring selections.
Select By: This option is just to toggle Ignore Backfacing on or off.
Edit UVs: Press the Open UV Editor button to open the UV Editor window, or alternatively you can press Control-E.
Reset UVWs: With the help of this option, you can reset the UVs. You can also save and load a UV file.
Map Channel: By default it should be set to 1, but you can have more than one map channel. You can open two different types of unwrap on the same asset, just by switching the map channel.

Step 8

When we apply the Unwrap UVW modifier, some green lines appear on the model. These green lines are clearly visible, even when we turn off the material. Don’t worry about these green lines, they are just seam lines because the Unwrap UVW modifier applies a generic unwrapping by default, which is not very useful.

Step 9

Have a look at the UV Editor box. It shows a generic unwrapped map. Here you will see everything is merged together. So we need to reopen all the parts one by one.

Step 10

First of all, press Control-A to select all the UVs and move them outside the UV box with the Move Selected Subtool tool.

Step 11

Next go to Mapping > Flatten Mapping.

Step 12

This opens the Flatten Mapping dialogue box. If you want less seams, you can increase the Face Angle Threshold value, or else just press OK with the default values.

Step 13

Flatten Mapping breaks the UVs into many big and small parts. These UVs split according to their face angles.

Step 14

The seams lines (green) have changed according to our new unwrapped UVs.

Step 15

Open the Material Editor by pressing M , and turn on the Show Shaded Material in Viewport icon. Now you can see the checkers on the model, but we need smaller checkers so the stretching will be more visible.

Step 16

To increase the numbers of checkers, increase the Tiling values of U and V. There are no specific values needed, as we just want small checkers. So adjust the values according to your needs. In my case, I changed the Tiling value to 20 for both U and V.