This tutorial illustrates how to create a wireframe sphere, by creating a grid texture, and then using the Sphereize filter.

1
Create a new image, 800x800 pixels.

Go to the Channels window, create a new channel , and select the Rectangular Marquee Tool.

Holding down Shift, draw a selection about 25x25 pixels.

To see how big your selection is, open the Info Palette, by going Window > Show Info.

Press D to select White as the foreground color, and then fill the selection by pressing Alt+Backspace.

2
In the menu, go:
Select > Modify > Contract... 2 pixels

Press Delete to clear the selection, and then use the arrow keys on your keyboard to nudge the selection up and to the left by 2 pixels.

Edit > Define Pattern

Create a new channel , select the Paint Bucket Tool .

Then, go to the Options palette.
Window > Show Options

Change the Contents dropdown to Pattern, and then click inside the new channel to fill it with the grid pattern.

3
In the Channels window, click on the Load Channel as Selection button.

Go back to the Layers window, and create a new layer.

Press D on the keyboard to select Black as the foreground color, and then press Alt+Backspace to fill the selection.

Ctrl+D to deselect.

4
Click and hold down the Rectangular Marquee Tool button, and select the Elliptical Marquee Tool

Holding down Shift, make a circular selection filling up most of the image.

Filter > Distort > Sphereize... Amount 100

Select > Inverse

Edit > Clear

Ctrl+D to deselect.

To get rid of the jagged edges, resize the image to 400x400 pixels,
Image > Image Size...