actually, i alway model such things. starship blasters, ey? I learned a way to make a blast weapon from a single plane object.
Step 1:
Create a plane cube from about 40 pixels height and 400 pixels width (you can change the width if you want your blast longer or shorter)
Step 2:
Get a transparency texture. i must be a circular object, fading out to the edges. the white must be non-transparent when you apply it, and the black should be transparent. here is an example:
Step 3:
Apply the transparency texture. it should be stretched along the long side of your plane cube. Now, go to a texture option that you can define in your program as "emmissive". Turn it to 1 or 2. (2 makes it more brighter). It comes to the point that you should make the plane cube emit light. like a lamp or so, you know what i mean? Now give a color to the emmissive option. i'd say green, but you may choose any color for such a blast.
Step 4:
into a scene, if you want to make an image, just put it somewhere and turn on the option to make the plane cube face the camera, so that you always see the side. (its a 2 dimensional object so you must make sure its not visible for the camera.)
if you want to make an animation, simply keep the option for facing the camera with its side turned on, then put it at the blast source, and make it follow a path to its hit object. you're done. This ALSO saves you TONS of rendering time.
I hope this little tutorial was helpful.
