OK I am making a space battle anim. I have like 20 turrets that will fire laser. I want each of them fire 1 laser each 20 frame. I know I could do it by making an alpha anim for each laser but it will be very long and i will have to make like 200 differend material. Is there a way to make something like that? (if some of you saw the intro anim of freespace2 they know what I am talking about…) Thank for your help! 
im not quite sure what you mean, but you were talking about materials, heres a laser tutorial:
http://http://dittohead.blender.tripod.com/Sabretut/Colour.html
if you are meaning that when you want them to dissapear after a while i don’t think theres a way. 
tx but I was not talking about that…I know how to make the laser material! 
ok what I want is this:
I have a turret. I what it to fire a laser each 20 frames. The problem is that the laser must be invisible before it is launch and then became visible and then became invisible when it will touch the target. I know I can make it by animating the alpha of the material but if I use that method it will take me like 3 week to animate only the laser and I will have to make a single material for each laser (so about 200-+ material. :-? ). If someone out there already make a space battle plz help me! Thank alot!
Ever thought about using a particle system and using your laserbolt as an object coming out of the emitter?
I’m sure you can slow down the particle system to meet your needs.
I haven’t tried this, but maybe putting a time IPO on the object and material would work. I don’t think it would be a super-fast fix, but way quicker than making every laser indiviually.
Wow tx…I never tough of that! Thank you alot!
using a Time IPO will only work if the turret is not moving though…
Martin
Ok,
I parented the object (laser) to the particule emitter and then I pressed duplivert. I tweak the particule a bit and now it look very nice when I don’t move the turret. But when I rotate it to fire a little up or down all the ‘‘laser’’ that have already been launch rotate too…Can I make them stay in the same position? Thank you