Loading the Gun

Contents

Putting the Projectile into the Barrel

Start with an empty scene. Read buckyball.pdb and barrel.pdb. barrel.pdb happens to place the barrel off of the screen in the default viewpoint. To find the barrel, place the mouse in the center of the screen, hold shift-middle and drag down to reduce the scale, then put the mouse back in the center of the screen and wiggle it around until you see the barrel. Orient the barrel horizontally in front of you and place the buckyball beside the center of the barrel:
Change the viepoint so you're looking down the barrel, and drag the buckyball to the center of the barrel:
Convert all objects in the scene to DesignAtom's, start time, and turn the scene to look at the outside of the barrel and make sure that none of the buckyball protrudes outside of the barrel.

Putting the Propellant into the Barrel

Orient the barrel horizontally in front of you. Select all atoms in top half of the barrel and press "i". This will cause the top half of the barrel to become invisible. The atoms still exist and do physics normally, but you can't see them or select them. Rotate the point of view so you can see into the remaining visible part of the figure:
Use shift-comma to create two hydrogen atoms between the projectile and the capped end of the barrel, and use "l" to link them to each other:
If we have only 100 hydrogen atoms in the chamber, there may not be enough pressure to overcome the attractive force between the barrel and the projectile; the projectile sometimes goes to the end of the barrel, comes out a little ways, and then retreats back into the barrel. 250 hydrogen atoms seems to be sufficient to get the projectile to exit the barrel. Select the hydrogen molecule and press control-C a few times, until the string of copies looks like it is about to extend into the projectile or the capped end of the barrel. Then take the last selected copy and move it with the mouse to a less crowded part of the chamber and press control-C some more.

At any time you can count the number of hydrogen's you've created by doing the following:

Keep creating hydrogens until you have about 250. If you appear to run out of room, make everything visible, rotate the barrel a randomly-chosen amount, and make the top half of the barrel invisible again. By taking a different cross section you can see empty spaces you couldn't see before.

When you're done, make everything visible and rotate the barrel to make sure all the hydrogen is inside the chamber. If any is outside, delete it and add more hydrogen inside the chamber.

The final result looks like this, with the barrel invisible:

Save this as buckygun.pdb. The hydrogens are arranged in physically unrealistic strings, but we'll fix that in the next section.
Copyright 2000 Tim Freeman <tim@infoscreen.com>