Explode

Tired of looking at Suzanne's ugly face? Itching to make her head explode? You've come to the right page. Just in case you're an animal lover though, we'll make a simple sphere explode instead. And in the process you will learn something not only about the explode modifier but also about Blender's particle system. Note that a particle system must always be attached to an object (it's actually a kind of modifier) so we must FIRST add the object and THEN add the particle system.

  1. Replace the default cube with a UV Sphere mesh (subdivide in tool shelf?)
  2. Subdivide the sphere once by going to Edit mode then clicking the Subdivide button in the tool shelf (press T if the tool shelf is not visible). Return to object mode.
  3. Add a particle system by clicking the '+' sign in the particles panel (open that panel just as you would open the materials panel, the world panel or the render panel).
  4. Already you can get a result by running the 'animation' - press Alt-A to start and stop the animation. When you do that you should see a thousand particles gradually released during the first 200 frames. Each particle falls for 50 frames and then reaches the end of its 'lifetime', dies and disappears. Is the emissions section of the particles panel starting to make sense?
  5. Now add an Explode modifier to the selected object. Notice that a 'particle system' modifier is already present in the modifier stack.
  6. Press Alt-A again. The sphere doesn't really 'explode' - it gradually disintegrates over a 200 frame period. Since all the parts fall for exactly 50 frames they form a rough sphere when they reach the end of their fall! The pieces of the sphere are not 'particles' as such and don't disappear when the 50 frames are up. Wondering what those red marks are in the timeline? They indicate that information has been 'cached' to allow the animation to run faster next time.
  7. Try pausing the animation half-way through and render a still image (F12). You should get a nice result where each particle gets a pretty 'halo' effect. If you don't like the halo effect you can turn it off in the 'render' section of the particles panel.
  8. Add a Solidify modifier to give the fragments of the sphere some thickness. A thickness value of about 0.05 works well.
  9. In the timeline window, set the 'end' of the movie to 70, ready for the sudden explosion we are about to set up.
  10. All the following changes take place in the properties panel. Each time you make a change briefly run the animation to see what difference it has made. In the emission section, set the 'end' value to 2 so that the explosion happens in a very brief time and looks like a real explosion. You can even let the animation run continuously and your changes will affect the running animation!
  11. In the physics section, switch from Newtonian to fluid to get more randomness.
  12. Increase the number of particles to 10 thousand. Now you're talking!
  13. In the 'Field Weights' section, reduce the gravity field weight to about 0.3
  14. In the emission section, set the 'random' value to about 0.4. This causes the particles to have lifetimes that vary randomly from the 'lifetime' value you have set (50).
  15. We still have the problem that the fragments of the sphere do not disappear at the end of their lifetimes (unlike the particles). In fact, they even rotate and align themselves in the same direction in a very unnatural way! Solve these problems by turning off the 'dead' option in the explode modifier properties (not the particle properties panel). This means that dead fragments will not be shown.
  16. Try hiding the particles by choosing 'none' in the render section of the particle properties panel.
  17. Try pausing the animation and doing a still render (F12) both with and without the particles.
  18. Now it's time for you to experiment with explosions yourself. But don't even think of blowing up Suzanne!