Your online Softimage Educational Resource

The blog has been online for more than 4 years and there’s still not a single post even remotely related to the delicious brew called coffee… Perhaps it will someday, but in the meantime you can read the articles about Softimage. Most of the material are tutorials and Q&As I’ve written for 3D World Magazine sometime between today and 2003. If you have any questions please don’t hesitate sending me an email.

Thanks to Letterbox Animation Studios for hosting all the scene files.

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Tuesday, August 5, 2008

Exploding Wall

By assigning random values for the initial velocity for each of the bricks, you can easily create the effect of an explosion.
While constructing scenes certainly is rewarding, it just won’t come close to the fun of blowing it all up. If you don’t’ have a brick wall at hand you can use the brick_wall.scn scene included on this issue’s CD. Select the ground_object and press [4] to switch to the Simulate Toolbar. While the ground object should be included in the simulation we don’t want it to be affected by the gravity, so from the Create > Rigid Body menu chose Passive Rigid Body. Scroll down to the Rigid Body Properties section and set the Elasticity to about 0.2 and both the Static and Dynamic Friction to about 0.75. The complete opposite is true for the bricks, so select all of them (66 in total) and from the Create > Rigid Body menu chose Active Rigid Body. Click the Lock icon in the Rigid Body PPG to lock it in place as you’ll return to it in a second. From the Modify > Rigid Body menu chose Edit Simulation Properties… In the PPG, change the Play Mode to Standard and check the Caching Checkbox. You’ll probably want to increase the Accuracy later on, but leave it quite low for now due to the otherwise decreased performance.

Return to the bricks Rigid Body PPG and start by increasing the Mass to 10. This will give the bricks enough weight to keep them from bouncing around, but still maintain some interesting motion. Under the Surface Properties set the Elasticity to about 0.075 the Static Friction to 0.1 and the Dynamic Friction to about 0.6. In conjunction with the Mass, these parameters will determine there characteristics of the bricks. In the Dynamic Initial State section, switch to the Velocity tab. Enter R(-10.10) as the value for the LinVelX, R(40) as the LinVelY and R(20) as the LinVelZ. The R() command will give each brick a unique and random value in the range you enter inside the parenthesis. The higher the number, the stronger the explosion will come of. Use the above values as a guide and play with different settings, preferable one at a time, till you’re happy with your demolition…

The project files used in this tutorial can be found at:

Once you get the overall motion playing nicely, you can modify individual bricks to enhance it even further.

Quick tip
Use different values (range) for different parts of the wall. The bricks closer to the center of the (imaginary) explosion should have higher values than the ones further away.