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Pitted, Scratched Metal: Transparency Maps

Author: Gary_P

Tools Needed

* Photoshop or other editing software

Support Files

* finished.zip

Introduction

This is part two of the pitted, scratched metal tutorial, showing how to create a quick and easy transparency map. I used a sewer grate for the test image and I showed you how to create the metal. I have included a finished graphic and a transparency map, so you can see what it look like.

100-1168.jpg

Step 1 - Step 1 - Using a Base Texture

Start Photoshop and create a new document 1000 x 1000 pixels.

Either create the pitted, scratched metal, or use your favorite texture that looks like the grate you want to build.

For demonstration purposes, I'm going to use the pitted, scratched metal texture I created in the other tutorial, and I'm using it at 1000 x 1000 pixels.

Step 2 - Step 2 - Setting Up

Turn on the Grid

Menu: View | Show | Grid

PC: Ctrl + Alt + '

I turned on the Rulers too.

Menu: View | Show Rulers

PC: Ctrl + R

Open the Grid settings window and set the grid to have a gridline every 50 pixels with 1 subdivision as shown below:

100-1169.jpg

You can open this window either by double clicking on the rulers or by using the menu.

Menu: Edit | Preferences | Guides and Grid

Next make sure you turn on Grid snap.

Menu: View | Snap

PC: Ctrl + ;

We are turning on the grids so when we place our “holes” into the plate that we will not have to line them all up by hand.

Step 3 - Step 3 - Selecting the Holes

We could use the Marquee tool to select our cutouts and create our holes, but the original sewer grate has circular holes.

For this I am going to show you a trick.

Turn on Quick Mask mode by clicking the right button just under the foreground and background in the main toolbar.

100-1170.jpg

Photoshop Trick:

The fastest way to draw a straight line in Photoshop is to single click at the start of the line then shift click the end of the line.

This will create a straight line between the two.

If you have the Grids and Snaps turned on, you will not have to worry about all the lines matching up.

All you need is to be close to the grid lines to create clean lines all in rows and columns.

Click on the paintbrush tool and select a brush size of 40 pixels.

Make sure the mode is set to Normal, and the Opacity is 100%.

Also make sure to choose a hard-edged brush and not a fuzzy brush.

With the paintbrush selected, single click on the first grid line from the left.

This will create a red dot.

You don't have to be centered on the grid, only close, and the snap will do the rest.

Count 4 spaces over, then Shift Click the end point of the line and you will have something close to what is shown below:

100-1171.jpg

Skip a line then repeat this again for the second line, then repeat it again.

100-1172.jpg

Skip a grid line vertically, then repeat all the way down until you have what is shown below:

100-1173.jpg

Now we can turn these red lines into selections by turning off Quick Mask mode, by clicking the left button just under the foreground and background in the main toolbar.

100-1174.jpg

Note:

Before you do this, you could add some vertical selections to make it look more like the original grate.

I have not included that, but you may use any pattern that you wish.

You will notice that now we have a selection, but it is not the holes that are selected, it is the whole grate.

That is not what we want.

You can fix that by inverting the selection.

Menu: Select | Inverse

PC: Ctrl + Shift + I

Only the holes are now selected.

If we produce a black and white transparency map from this alone, it will look fake and unfinished.

What I would like to do is create an indent in the metal, then cut the metal out.

Step 4 - Step 4 - Making Holes

Let us enlarge the holes just a bit, but first we should save the selection (we would not want to lose the selection we took so long to make).

Save the selection.

Menu: Select | Save Selection…

Name the selection Holes, and click OK.

100-1175.jpg

Now we will make the selection bigger by expanding it by a few pixels.

Menu: Select | Modify | Expand

Expand the selection by 5 Pixels as shown below:

100-1176.jpg

Hey! Now we have bigger holes.

Make sure the background layer is selected if you have multiple layers and Copy and Paste this layer.

PC: Ctrl + C then Ctrl + V

You should now see another layer labeled layer 1.

Let's emboss this to create a dimple effect for our holes.

Menu: Layer | Layer Style | Bevel and Emboss…

Set the Highlight Mode color to an off white, then set the Direction to Down as shown below:

100-1177.jpg

Your texture should look like this:

100-1178.jpg

Almost there!

Step 5 - Step 5 - Creating the Trans Map

Reload the previous selection.

Menu: Select | Load Selection…

100-1179.jpg

Background:

When you create a transparency map, you create a gray scale image where everything that is white is solid and everything that is black is transparent.

Everything that is in between (like gray) is semi-transparent.

What we want to do is create an image where the whole thing is colored white and the holes are colored black.

Create a new layer by either clicking on the little button that looks like a piece of paper with the top corner bent, or use the menu option.

Menu: Layer | New Layer…

Name this layer Transparency

100-1180.jpg

Click on the reset button to restore the foreground and background colors to black and white, or press the shortcut D.

100-1181.jpg

Click on the foreground color (black) to make it active.

Make sure your new layer is selected.

Using the Paint Bucket tool, click INSIDE one of the selections to fill the holes with black.

Next we want to color the rest of the image to white so invert the selection.

Menu: Select | Inverse

PC: Ctrl + Shift + I

Click on the background color (white) to make it active, or press the shortcut key X.

100-1182.jpg

Make sure your new layer is selected.

Using the Paint Bucket tool, click OUTSIDE the selections to fill the background with white.

100-1183.jpg

Unselect everything.

Menu: Select | Deselect

PC: Ctrl + D

Step 6 - Step 6 - Saving Our Texture

Believe it or not, we now have 2 textures in our possession.

1. Our Metal texture and

2. Our Transparency Map.

They are on 2 different layers.

Turn off the Transparency layer by clicking on the eye at the far left of the layers box.

Then turn on the other two layers.

100-1184.jpg

Now save your picture as a jpg file. You could use any file type that your graphics package can use.

File | Save As…

Turn on the Transparency layer by clicking on the eye at the far left of the layers box.

Then turn off the other two layers.

Now save your transparency picture as a jpg file. You could use any file type that your graphics package can use.

File | Save As…

The metal picture is the actual texture of the model and the transparency picture gets used as the transparency.

Here is a quick render of my sewer grate.

100-1168.jpg

I hope this tutorial was helpful to you, and you may email me with any questions.

Happy Rendering!