Bridges are a good example of Collapsable Sprites. The bridges which appear to be "truly 3D" are actually made up of sprites. These sprites can be shot down by an explosive. Another example of a Collapsable Sprite is a street sign that can be blown away by an explosive.
Collapsable Bridges
A Collapsable Bridge is made by placing a floor-aligned sprite and resizing it so it fits over a gap. Make it blocked, and make sure it is two-sided by using the 1
key. Give the bridge sprite a unique Hi-Tag to make it collapsable.
To make a 3D Collapsable Bridge, just make a regular Collapsable Bridge, but add blocked sprites to the bottom and sides of it. 3D bridges require a lot more work, but they look much better. To make the entire 3D bridge collapsable, give all of the bridge sprites the same unique Hi-Tag.
Note: Ugly graphic glitches can occur when making 3D bridges. Some sprites will show through other sprites when they shouldn't be visible. To fix this, make all of the bridge sprites one-sided by using the 1
key. That way, only the side that the player should be able to see will be visible, and the other sides (which caused the graphic glitches), will be completely invisible and will cause no more problems.
Collapsable Sprites
To make a sprite fall when an explosion occurs nearby, give it a unique Hi-Tag. Any sprites sharing the same unique Hi-Tag will fall at the same time.