okay. best thing is a starting point. see attached. create an object, call it 'smoker', and in its init field put
[] exec "smoker.sqs"
when you want it to stop, set the global variable
stop_smoking to true.
this is for chimney smoke, which is light grey. smoke from explosions is usually black. in the script you will see the variable
_color with lots of numbers - sets of four, like this...
_color= [[0.5,0.5,0.5,0.3],[0.4,0.4,0.4,1],[0.5,0.5,0.5,0.6],[0.6,0.6,0.6,0.5],[0.7,0.7,0.7,0]]
that is an array containing color arrays, 5 of them. that means in the lifetime of one particle it will morph through all 5 colours. each colour is a set of 4 numbers: red, green, blue and alpha. the colours are self-explanatory. alpha is how transparent it is.
a value of 1 is 100%, a value of 0 is 0%. play with the values and see what colours you get.
as you rightly point out, the drop command is tricksy, and this thread really belongs in the advanced board. having said that, i've given you the script, all you need to do is play with the numbers. not all that advanced