Trigger a change...
 

The program I am designing has a wizard shooting a thunderbolt or fireball (depending on the button pushed) at a knight. I have the scene set up with the fireball and thunderbolt attached to the wizards hand and they are both using opacity 0. What I need to know is how to make it become visible at the moment that the key is pushed. I can make it move, but I don't know how to change it's opacity when the key is pushed.

I am not good at explaining this kind of thing so if you need me to explain it in another way let me know. If anybody knows how to do this please let me know.

Go to the objects properties, you can drag out the property opacity to the method, and from there you can change it to 100 and put it in the "when key is pushed". Hope this helps. :D

thank you so much! that is exactly what I needed to know! I can't believe I couldn't figure that out