PART II: The Space Scene
Step 16: Asteroids

Asteroids are rocks floating through space. We will use a few filters and some new tools as we insert (at least) 3 asteroids into our space scene.

1. Open your Space file in Photoshop
2. Turn off the visibility of all of your layers
3. Insert a new layer at the top of your layer stack and name it Asteroid1
4. Click the Lasso Tool and set Feather on the Lasso Tool's option bar to 5px...
   
5. Press Ctrl+R on the keyboard to turn on Photoshop's Rulers
6. Zoom in until you can see an area of your image that is about 300x300 pixels in size - use the ruler you just turned on to determine when you have zoomed in enough...
   
   The ruler above is displaying approximately 335 pixels

Since many of us are using different screen resolutions, it is not possible for me to give you an exact Zoom amount. You want to zoom in to a point where you can create a nicely shaped asteroid and ensure that it is not too big, as having an overly large asteroid will cause problems later on.

7. Draw an ovoid shape...
   
   Don't draw it too close to the edge of your image - keep in mind that you will move it later

An important thing to keep in mind here is that you want to create an asteroid shape that is oval. In other words, make sure it is roundish, kinda like a fat potato or a dented egg. Avoid creating an asteroid that is oddly shaped or has strange things sticking off of it such as this...

While asteroids like this are physically possible and in fact do exist, they are very rare. Rounded asteroids are far more common (asteroids tend to get rounded by colliding with other asteroids which, over time, breaks off protruding pieces of rock) and will look much better in our space scene because they will be easily recognizable as an asteroid where the shape above will cause many viewers of our image to say "huh?"

8. Press D on the keyboard (remember what this does?)
9. Press Alt+Backspace on the keyboard (remember what this does?)
10. Press X on the keyboard (this is the keyboard shortcut to swap the Foreground and Background colors) - you should now have white as your Foreground color and black as your Background color
11. Click Filter then point at Render and click Clouds - your shape should look something like this...
    
    Keep in mind that you will have a different shape than mine
12. Click Filter then point at Render and click Difference Clouds - your shape should look something like this...
    
13. Click Filter and then click Filter Gallery...
    
    to open the Filter Gallery window
14. Click the Sketch group and then click on Bas Relief...
    
15. Make Detail and Smoothness match the image below...
    
    For the Light option, you can choose either Left or Right, so click on each one and see which one gives you the best looking asteroid
16. Click OK to exit the Filter Gallery - your asteroid should look something like this...
    
17. Press Ctrl+D to deselect your asteroid

So far our first asteroid looks pretty good. We are not done with it, but let's take a moment right now to quickly create another asteroid and then we will do some additional editing on both of them to make sure that they do not look exactly alike. We are going to create the second asteroid by cheating a little and duplicating pieces of the first one.

18. Press Ctrl+R to turn off the Rulers
19. Insert a new layer at the top of the layer stack and name it Asteroid2
20. Click the Clone Stamp Tool...
    

21. Double-click the Hand Tool...
    
    This will set your zoom level so that you can see your entire space scene at once (at this point your space scene should contain only your first asteroid and the transparent checkerboard pattern because you should still have the visibility of all of the other layers turned off)
22. Click the Clone Stamp Tool and in the Brush Preset picker select the Soft Round brush and set the size to 30 px

To use the Clone Stamp Tool, we first need to determine the area of the image we wish to copy - which for us is parts of our first asteroid - and then we need to determine where we want to copy the parts of the image to - which for us will be in a blank area beside our first asteroid. Let's try this and see how it works.

23. Press and hold the Alt key - notice that as you hold the Alt key down that the cursor changes to a tiny target...
    
    this is how Photoshop tells you that you are about to define an area to clone from - click in the center of asteroid 1 and release the Alt key

It may look like nothing is happening, but Photoshop remembers where you clicked and will begin copying what is at that spot to the new area when you begin to draw.

24. Move the cursor to the empty area beside asteroid 1
25. Click and drag the mouse around - notice as you do this that Photoshop places a tiny + sign over the spot where you originally clicked in direction 23 and that as you drag the tiny plus sign is following the motion of your mouse

Most of you will notice a slight problem at this point - nothing is actually being drawn. So what's going on? It turns out that by default Photoshop is set up to clone regions only on one layer, and since the layer we are currently drawing on (which should be Asteroid2) is blank, we are not actually drawing anything right now. To fix this problem, we need to make a quick adjustment to our Clone Stamp Tool's options bar.

26. On the Clone Stamp Tool options bar, set Sample: to Current & Below....
    
    This will allow us to pull from not only our current layer but also from the layer directly below it
27. Alt+click once more on the center of asteroid 1
28. Move the cursor to the empty area beside asteroid 1 and click and drag the mouse around - you should now be cloning asteroid 1 in the new location...
    
    Draw until you have created a new asteroid approximately half the size of asteroid 1...
    
    Try not to make the overall shape of your second asteroid the same shape as the first one, and avoid the edge of asteroid 1 (it has a less than perfect edge that we will need to deal with later)

Remember that since Photoshop is copying whatever is in the original area that if you go off your asteroid that nothing will be copied. Looking at asteroid 2 at this point you may notice that it looks like a miniature version of asteroid 1 (because it is). Let's do some quick adjusting to make asteroid 2 look a little more unique.

29. Make sure the Asteroid2 layer is the active layer
30. Click Image on the menu bar and point at Adjustments and click Invert...
    
    This turns the dark parts of our asteroid light and the light parts dark...
    
31. Press Ctrl+T on the keyboard to enter free transform mode
32. Change the size of the asteroid in some way - you can drag any resize handle to make the rock wider, thinner, taller, shorter, or use a corner to adjust both height and width at the same time - then rotate it so that it sits at a different angle from asteroid 1...
    
33. Press Enter to apply the transform

You should now have two asteroids that hopefully do not look like exact copies of each other. If you are happy with your two asteroids then skip the following direction, but if your asteroids still look too much alike, do this:

34. If your asteroids still look alike, click the Eraser tool and use a Soft Round size 50 px brush to remove parts of asteroid 2's edge until it appears unique - remember to keep it roundish

Now let's make a quick adjustment that will give our space rocks some extra dimension and help to keep the surface looking nice when we shrink them down in the coming directions.

35. Click the Sharpen Tool...
    
    You may have to right-click the Blur Tool and then select the Sharpen Tool...
    
36. On the Sharpen Tool options bar, set Strength to 50%...
    

The Sharpen Tool increases the detail of our selection, which will help to make our asteroids look like they are actually made out of rock.

37. Make Asteroid1 the active layer
38. On the Sharpen Tool options bar set the brush to Soft Round and the Size to 30 px
39. Click and drag an area of the asteroid you want to sharpen - notice this process does not result in a huge change...
    
    Do not sharpen the entire asteroid or your rock will look unnatural - we just want some additional detail so our rocks look like they actually have peaks and valleys and will maintain a sharp, crisp appearance when we make them smaller
40. Repeat the above three directions on asteroid 2

Two asteroids down, so we just need to create one more. Keep in mind that you can create more asteroids if you wish to make your scene unique (3 is the minimum), but don't go crazy and add in tons of asteroids or your planets will become fiery-asteroid-crashing-death-traps.

41. Create an additional asteroid (name it Asteroid3) by going back to direction 3 and following directions 3-17 and directions 35-39

Creating asteroid 3 from scratch ensures that our third asteroid is completely unique and different from the other two. DO NOT simply create your third (or any other) asteroid by duplicating asteroids 1 or 2. If you do this you will get NO credit for having created your final asteroid. Also, your space scene will look stupid. Think about it: there are not two identical asteroids floating around the universe. Take some pride in your work.

At this point, if we turn on our other layers we will see that our asteroids are actually pretty bright when compared to the rest of the stuff in our image...

We need to make a quick change to each asteroid so that it looks more like it is actually a rock flying through the blackness of outer space.

42. Make Asteroid1 the active layer
43. Click Image and point at Adjustments and click Levels
44. Click on the Levels window's title bar and drag it to a spot where you can see both the Levels window and your asteroid 1
45. Drag the black Input Levels arrow...
    
    to the right until your asteroid has a nice combination of light and dark areas - what amount you use is up to you, but a value between 70 and 120 will work best
46. Click OK
47. Repeat the above 5 directions for asteroids 2 and 3 (it is ok to set different level amounts for each of your asteroids - the amount of light and shadow on each rock depends on where they are in your space scene and thus will not be the same for each one when you move them around a few directions from now)

Things are looking pretty good at this point, but if you zoom in on asteroid 1 you will most likely see a potential problem...

Notice the strange white glow around the edge of the asteroid? This is left over from when we applied the filters at the start of this step and can end up being a real issue when we resize our asteroids or when we move them around and place them over other elements in our image and the white edge becomes noticeable. Let's take a quick second to remove this edge.

48. Make Asteroid1 the active layer
49. Ctrl+click on Asteroid1's layer thumbnail to select asteroid 1
50. Click Select then point at Modify and click Contract...
    
51. In the Contract Selection window, set Contract By: to 10 pixels...
    
52. Press OK
53. Press Ctrl+Shift+I to invert the selection (everything EXCEPT your asteroid1 should now be selected)
54. Click Edit and then click Clear...
    

This should get rid of most of your problem areas. Have a look at your asteroid and see if you have eliminated the glow problem. If you still have glowing areas...

You can simply click Edit and then Clear several more times to gradually eliminate it...

In the image above, I used Edit then Clear twice more to remove the glow outside the selection.

55. If glowing areas remain, simply click Edit and then Clear several more times

Be sure that you are using Edit - Clear to remove the edge of your asteroid and that you are not pressing the Delete key on the keyboard. Using the Delete key will work, but only once or twice. Pressing it any more than that will begin to impact the opacity of the entire asteroid instead of just the edge. If you have problems that using Edit - Clear a few times will not fix, then simply contract the selection, invert, and use Edit - Clear.

We now need to fix the other asteroids. Let's fix asteroid 3 first since we created it the same way as asteroid 1.

56. Make Asteroid3 the active layer and repeat the above 7 directions to fix its edge

Asteroid 2 should not have much of a problem with its edge because we created it a different way from asteroids 1 and 3, but let's take a look at it just to be sure.

57. Make Asteroid2 the active layer and zoom in on it and see if its edge needs to be adjusted - repeat the above directions if needed (note that a smaller contraction, such as 5 pixels instead of 10, may work best on asteroid 2)

Now that our asteroids are ready to go, let's get them in a more believable size.

58. Resize all your asteroids so they are in scale with the other objects in your scene - you can make them different sizes so that they appear to be different distances away (your asteroids should not be as large as your planets, but instead should be awesome little [but not too little] additions to your solar system)
59. Resizing your asteroids may make them brighter than what we want, so take a second now and have a look at your asteroids and see if they are too bright - if they are so bright that they stand out in your scene (they should appear to blend in and be an extra element in the background and not the focal point of the scene), simply repeat directions 42-47 to make them darker
60. Scatter the asteroids throughout your image
61. Select all of the asteroid layers...
    
62. Click the Create a new group icon
63. Rename the new layer group Asteroids...
    
64. Lock the Asteroids group

We have all of the pieces of our space scene in place, so all that is left is one final finishing touch.

65. Save your Space file