This tutorial explains how to create a simple 3D like metal fence. You will need a basic knowledge of selections and you will need to create a "base-rust" texture
Create a new channel. Make a rectangular selection 10x10 (or any other size) pixels using the Rectangular Marquee. Set white as the foreground color. In the main menu select Edit > Stroke. Set the Width value to 1 and Location to Inside. Click OK.
Shift the selection down and to the right 1 pixel using the Rectangular Marquee tool. Set black as the background color and press the Delete button to clear the selected area. Move the selection back to its original place.
In the main menu select Edit > Define Pattern. Remove selection (Ctrl+D). In the main menu select Edit > Fill to show the Fill dialog. Set the Content value to Pattern and click OK.
Create a new channel. Make a selection 1x10 pixels (or 1xX where X is the height of the cell you made in the first step) using the Rectangular Marquee tool. Reset and switch solors (press 'D' and 'X'). Select the Linear Gradient tool. Make a gradient from the top side of selection to the bottom side.
Make a selection 10x1 pixels (or the width of the cell you made inthe first step) using the Rectangular Marquee tool. Make a gradient from the right side of selection to the left side using the Linear Gradient.
Continue creating gradients until you get the kind of pattern you can see in the picture.
Using the Rectangular Marquee make a selection one pixel less in width and height, just as shown in the picture.
In the main menu select Edit > Define Pattern. Remove selection (Ctrl+D). In the main menu select Edit > Fill to show the Fill dialog. Set the Content value to Pattern and click OK.
Load selection from the first channel. In the Layers palette make your texture layer active (if you haven't created one, it's the right time to do so now). Click the Add Layer Mask button.
In the Channels palette make the second channel active. Select all (Ctrl+A) and copy it (Ctrl+C) to the clipboard. Create a new layer and paste from the clipboard. Group the new layer with the texture layer.
Set the Blending Mode of the new layer to Overlay. Done!