Spring RTS Engine

How do I do explosions?
http://springrts.com/screenshot.php?id=899

Is it a lups or ceg thing? and are there any lua examples?

Look at other mods for examples. CA has a ton of CEG and LUPs. Most explosions are CEG and LUPs are used for other effects such as aircraft/ weapon trails, or weather effects.

Assuming that image is the CA fusion...

Look in the armfus unit file, it explodes as ATOMIC BLAST.

Then look in the weapons folder for the atomic blast weapon file (atomic_blast.tdf).

In there you'll see the explosion graphic is NUKE_150.

A short trip to the effects folder and under it you'll see the nuke_150.lua file that contains the CEG definition for that visual.