There are three ways:
- Ingenious use of emitters to simply make one from the explosion center (it looks meh though)
- Have the explosion create a projectile shooting upwards and that projectile detonating to make the mushroom cloud. (good effects)
- Have the explosion create debris shooting upwards and detonating to make the mushroom cloud. (theoretically best effects)
The two last options require some extra scripting, for the projectile you obviously have to script the explosion (or the first projectile death event) to spawn a projectile and shoot it upwards. For the second option you need to manually script in an explodeOnDeath function for the debris because torque never thought debris blowing up mid-air would be a good idea, or something.
Personally the debris option has more potential because you can attach 2 trail emitters to debris, projectiles are limited to 1. I haven't gotten around to learning how to script all that much yet though so I haven't looked into it too much.
