Blender Game Engine - tutorial 1

STEP 1: Open a new (empty) scene in blender In the main viewport you will see the top view of a cube. You will also see a camera (the black wireframe icon) and a light (the yellow circle).
STEP2: If you hit the "0" on the numPad (View > Camera), you will see through the camera. Press "7" (View > Top) to return to the top view. The top view is good to be in when you are creating new objects. Blender likes to orient your newly created objects to the view you are in. So if you get in the habit of going into the top view ("7") when creating objects, everything will be created on a common plane and they will be easier to arrange later on.
STEP 3: You can switch between Orthographic and Perspective modes by hitting "5" on the numPad (View > Orthographic). It's a good idea to be in Orthographic mode when adding new objects. Like being in the top view, it just makes things easier to deal with later on. You can tell if you are in Perspective mode because things will look foreshortened. In Orthographic mode things will look very diagrammatic. Make sure you are in Orthographic mode. STEP 4: To select objects in Blender, right click on them. Try it a few times - right click on the camera, then on the light. Now right click on the cube to select it and hit "x". You will be asked if you want to delete the cube. Click OK to delete it.
STEP 5: Now we want to create a new object. New objects are created wherever the 3D cursor is. So, it should still be in the center, but if it isn't just left-click in the center of the grid to move it there (left-clicking places the 3D cursor). Press the "spacebar" and you will bring up the Hotbox menu. Select: Add > Mesh > Plane.
STEP 6: This gives you a plane that should look like a square with yellow dots in the corners. Blender automatically puts you in edit mode when you create an object. In this case, we don't want to be in edit mode. Hit "Tab" to exit edit mode (the four dots will go away and the plane will be pink, which means it's selected).
STEP 7: Click "s" to scale the plane up. Hold down the "CTRL" key while scaling to constrain it to tenths of a unit. You can see the numerical values of your operation in the lower left corner of the viewport window. Scale the plane up 10 time (until the number reaches 10.0).
STEP 8: Now hit "Tab" to return to edit mode. You should see the corners are yellow dots again. Those are vertices. In 3D geometry you will have a vertex wherever polygons are connected at their corners. When you move these vertices, you change the shape of the object. Right now, we don't want to change the shape of the square, but we do want to add more vertices. Click on the "editing panel" icon (F9). Now you have more options at the bottom of the screen.
STEP 9: Click on "Subdivide" in the Mesh Tools tab. Now you're plane has four quadrants. Click it again so it has sixteen.
STEP 10: Hit "a" to deselect all the vertices (hitting "a" toggles between selecting ALL and selecting NONE). Now hit "b" and click-and-drag a square around the nine vertices in the center of the plane.
STEP 11: Now you will want to switch from a top view to a front view. To do this press "1" on the numPad (View > Front). Now hit "g" which will means Grab. This grabs the selected vertices so you can move them. Now you will notice if you move the mouse around, the vertices move with it, which changes the shape of the object. STEP 12: Pull the vertices downwards, but don't hit the left mouse button yet. While you have the vertices "grabbed", hit the "z" key. That will constrain the translation to the z-axis (you can refer to the small colored xyz axis in the lower left corner of the viewport). Now hold down the "CTRL" key to snap the vertices to a grid unit. Bring the selected vertices down five grid spaces and click the left mouse button to confirm.
STEP 13: What you should have is a square "bowl" shaped object. Hit "Tab" to exit edit mode, then hit "0" on the numPad to switch to the camera's view (View > Camera). If you click-and-hold the middle mouse button, you can move your view around to see the object better. When you're done looking at the object, click "7" on the numPad to return to the top view (View > Top).
STEP 14: Click "5" to return to Orthographic mode (View > Orthographic). We will now create a ball that will bounce in our square bowl thing. Remember, new objects are created wherever the 3D cursor is, so if it isn't in the center, left-click to place it there. Now press the "spacebar" and you will bring up the Hotbox menu. Select: Add > Mesh > Icosphere. It should say "subdivision:2" - click OK.
STEP 15: Click "Tab" to exit edit mode, and click "1" to go to the front view (View > Front). Click "g" to grab the sphere and move it underneath the camera but above the bowl shape. Hit "0" on the numPad to switch to the camera's view (View > Camera).
STEP 16: Now that we have a ball and a place for the ball to go, we need to make the ball into an "actor" for the game engine to apply its physics to it. Go to the lower panel and click the little purple pac-man icon. This opens up the game engine options. Make sure the ball is selected (should be pink) and click on "Actor" right under the pac-man. Two more buttons appeared: Ghost and Dynamic. Click Dynamic. A bunch of new buttons appeared. Click "Rigid Body" and "Anistropic". We will discuss the meaning of these settings in a later tutorial. Right now we just want to see the game engine working.
STEP 17: Click "p" to start the game engine (P is for Play). You should see the ball fall down and roll around in the bowl for a while. That's it! You just created a physical simulation using the Blender Game Engine. Press "ESC" to exit game engine mode. In the next tutorial we will control an object's movement in the game engine using the arrow keys.