The obvious choice is to define a negative frame (say -100) in the
'Creation Frame' parameter under the Smoke Object.
(with Creation Frame Specifies Simulation Frame ‘on’ too).

This works for positive values (to delay the fluid generation) but fails for negative values (to have a big smoke colume 100 frames old at frame 1).

Is this possibler?

Or even Initial States?-so define frame 150 as my ‘new frame 1’ or initial
frame?
ral