Quote Originally Posted by Mouzafphaerre
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GAH! The engines file has nothing to do with wall towers. But I already knew that, oh well...
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Correct. The walls themselves appear to be hard coded. I remember seeing some comment notations about something related to the wall tower fire rate in the projectiles or units files (or other?). Think it had something to do with resetting the number of engines in siege units. Might have been a CA comment online though. From it I had the impression that it was hardcoded.

Afterall, aren't the arrow/javelin/sling/ballista/onager fire rates hard coded already? I am thinking that the siege engine fire interval is the only example of the game going around the projectile fire rate hard coding (and making it modable.)