Second Animation: A delayed solid cube
Now it is time to use some masks. We want to create two areas in which the animation plays back with 1 frame time difference. This creates a very interesting glass-like visual effect.
Start by creating a black and white image like the one below. You can use a paint program or do it in Blender. The easiest way to do this in Blender is to create a white material with an emit value of 1 or a shadeless white material on some bevelled Curve Circles. In this way, you do not need to set up any lamps. Save the image as mask.tga.
Switch to the sequence editor and move the meta strip that we made before out of the way (we will reposition it later). Add the animation of the solid cube (SHIFT-A>>Movie). Next, add the mask image. By default a still image will get a length of 50 frames in the sequence editor. Change it to match the length of the cube animation by RMB and GKEY to dragging out the arrows on the side of the image strip with the right mouse button.
Now select both strips (hold down SHIFT), press SHIFT-A and add a SUB (subtract) effect:
In the preview window you will now see the effect; the areas where the mask is white have been removed from the picture:
This effect is ready now; select all three strips and convert them into a META strip by pressing MKEY.
Now repeat the previous steps, except that you don’t use the SUB effect but the MUL (multiply) effect. This time you will only see the original image where the mask image is white. Turn the three strips of this effect into a meta strip again.
For the final step I have to combine the two effects together. Move one of the meta strips above the other one and give it a time offset of one frame. Select both strips and add an ADD effect:
In the preview window you can now see the result of the combination of the animation and the mask.
When you are ready, select the two meta strips and the ADD effect and convert them into a new meta strip. (That’s right! You can have meta strips in meta strips!)
Tip: Getting into a Meta Strip
To edit the contents of a meta strip, select it and press TAB. The meta strip will ‘explode’ to show its components and the background will turn yellowish/green to indicate that you are working inside a meta strip. Press TAB again to return to normal editing.
Third Animation: a tunnel
We want a third ‘effect’to further enrich our animation; a 3D ‘tunnel’ to be used as a background effect. This is really simple to create. First save your current work – you will need it later!
Start a new scene (CTRL-X) and delete the default plane. Switch to front view (NUM1). Add a 20-vertex circle about 10 units under the z=0 line (the pink line in your screen):
While still in Edit Mode, switch to side view (NUM3) and snap the cursor to the origin by locating it roughly at the x,y,z=0 point and pressing SHIFT-S. Select Curs>>Grid.
We want to turn the circle into a circular tube, or torus. For this, we will use the Spin function. Go to the Editing Context (F9) and enter a value of 180 in the Degr NumButton and enter ’10′ in the Steps NumButton in the Mesh Tools Panel. Pressing Spin will now rotate the selected vertices around the cursor at 180 degrees and in 10 steps:
Leave Edit Mode (TAB). With the default settings, Blender will always rotate and scale around the object’s center which is displayed as a tiny dot. This dot is yellow when the object is unselected and pink when it is selected. With the cursor still in the origin, press the Center Cursor button in the Edit Buttons window to move the object center to the current cursor location. Now press RKEY and rotate the tube 180 degrees around the cursor.
Now it’s time to move the camera into the tunnel. Open another 3D window and switch it to the camera view (NUM0). Position the camera in the side view window to match the figure below:
The camera view should look like this:
Tip: Missing edges
If not all of the edges of the tunnel are showing, you can force Blender to draw them by selecting All Edges Tog Button in the Mesh Tools 1 Panel of the Editing Context (F9).
To save ourselves some trouble, I want to render this as a looping animation. I can then add as many copies of it as I like to the final video compilation.
There are two things to keep in mind when creating looping animations. First, make sure that there is no ‘jump’ in your animation when it loops. For this, you have to be careful when creating the KeyFrames and when setting the animation length. Create two KeyFrames: one with the current rotation of the tube on frame 1, and one with a rotation of 90 degrees (hold down CTRL while rotating) on frame 51. In your animation frame 51 is now the same as frame 1, so when rendering you will need to leave out frame 51 and render from 1 to 50.
Please note that the number 90 degrees is not chosen carelessly, but because the tunnel is periodic with period 18, hence you must rotate it by a multiple of 18, and 90 is it, to guarantee that frame 51 is exactly the same than frame 1.
Second, to get a linear motion you need to remove the ease-in and ease-out of the rotation. These can be seen in the IPO Window of the tube after inserting the rotation KeyFrames. The IPO smoothly starts and end, much like a cosine function. We want it to be straight. To do so select the rotation curve, enter editmode (TAB) and select all vertices (AKEY) and press VKEY (‘Vector’) to change the curve into a linear one:
To create a more dramatic effect, select the camera while in camera view mode. The camera itself is displayed as the solid square. Press RKEY and rotate it a bit. If you now play back your animation it should loop seamlessly.
For the final touch, add a blue WireFrame material to the tube and add a small lamp on the location of the camera. By tweaking the lamp’s Dist value (attenuation distance) you can make the end of the tube disappear in the dark without having to work with mist.
When you are satisfied with the result, render your animation and save it as ‘tunnel.avi’.
Continued on page 3…
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