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	Realistic Gears Tutorial Author - Man1c M0g (http://forums.biorust.com/member.php?s=&action=getinfo&userid=1)

Lets face it - without gears and cogs we would all still be in the stone age. For hundreds of years these mechanical marvels have enriched our lives and, over time, have allowed us to make clocks, VCRs, and other modern personal items a reality. As any mechanical engineer will tell you, however, they take lots of time to design, because each 'tooth' has to intermesh with the 'groove' of another gear. Scale a simple gear up to include various sizes, each with differing numbers of teeth, albeit all meant to fit together, and you have a real logistical nightmare on your hands! Whilst this tutorial will not go into the actual theory of gear design (that's more the domain of a university course), serious efforts will be made towards producing a final result that is scalable and yet creates gears that will intermesh reasonably too.

	Step 1: Create a blank 200px by 200px document and fill the background with anything you like (white may be best at first). Create a new transparent layer on top, select it, and, using the standard rectangular marquee tool draw a selection 32px wide by 186px tall. Using the 'fixed size' abilities of the tool will definitely help here. Now choose Edit > Fill from the menu and fill the selection with 50% grey. Do not deselect yet.
	Step 2: Now choose Select > Transform Selection from the menu and rotate the selection by 45 degrees. You can do this by entering the value directly into the toolbar or by holding down SHIFT on your keyboard and dragging outside the selection (this moves the selection in 15 degree chunks). Press ENTER to finalize the selection changes and fill this new selection with 50% grey as in step 1. Repeat another two times to get a result similar to the one on the left.
	Step 3: Using the elliptical marquee tool, draw a circle 144px by 144px in size and move the selection into the middle of the rectangular shapes. Fill it with 50% grey as before. Now run through my anti-aliasing tutorial with a Gaussian blur of 5 to smooth out the edges and get a result similar to that on the left. Extra: A quick analysis of the shape via a duplicate (i.e. the blue gear) shows they fit together well.
	Step 4: Now that we have the basic shape designed, all we have to do is make it look metallic. With the gear shape layer still selected in the layers palette, choose Layer > Layer Style > Bevel and Emboss from the main menu and duplicate the settings on the left. The gloss contour is a standard one included with PS called 'rolling slope - descending'. Feel free to mess around with the contour a little, though, to tighten up the highlights as you see fit.
	Step 5: Without leaving the layer effects dialog, progress onto the contour subsection and enter the settings shown here. Now Press OK.
	Step 6: The resultant shape is a little dark, so brighten it up by choosing Image > Adjustments > Brightness / Contrast and setting both sliders to +100. If all has gone well you should now have a gear that looks like the one opposite. As you will quickly notice, however, the main area keeps a solid colour. This can be quickly rectified by finding a nice metallic texture and mapping it over the shape. If you don't know how to do this, my Texture Mapping tutorial should be your next port of call.
	Step 7: Here's one I did earlier. Don't forget to include a hole or axle in the middle of your shape, or there will be no way to anchor it to anything. This isn't essential, of course, but we are aiming for realism after all... ;)
	Variations: Don't be put off by the apparent complexity of this example, because its really not any harder to make than the one above. Just use few more layers with circular selections, copy layer styles across, and voila - you have a much more impressive cogwheel. With a little imagination and experimentation you'll be able to create fantastic-looking mechanical marvels in no time.

Footnote: Want to create additional gears with more/less teeth, but which also maintain compatibility with the example I have above? Its simple if you apply some basic mathematic principles! If, for example, you wanted to make a gear 1/2 of the size, you'd halve the height of the box in step 1 (but keep the width the same), halve the circle size of the circle in step 3, and double the selection rotation amount in step 2. This will give you a tiny gear with four teeth. As you can probably guess, if you want to double the number of teeth, just do the inverse.