I want to make a length of animation run at half the speed. So I would do this:-

If the animation is n frames long, make it 2*n frames long.

for A in poser.Scene().Actors():

. for j = n (-1) 1 :-

. . for P =  each parameter dial in turn of actor A :-

. . . B = all the frame information (value, whether it is a keyframe, spline settings) for frame j of parameter dial P of actor A

. . . delete frame j of parameter dial P of actor A, if it is a keyframe

. . . delete frame 2*j of parameter dial P of actor A, if it is already a keyframe

. . . set frame 2*j of parameter dial P of actor A to the value and keyframe settings of B, if B is a keyframe

Please, has this been done before?

Most of it looks easy, but how could I pick up and set the spline settings?

I would render at 30fps save it in AVI and then in your movie editor you should be able to control the rendered scene speed in the movie eidtor  I use adobe premiere  and i can slow it own to 3 fps if i need to.  Just a short cut I use  for slow motion shots. :)

Thanks. But after I have done what I described in the first message in this thread, I may need to edit the result some more.