Starting with the solo pose blend file:
adjusted the start and end frames to 0 and 80 respectively
copied whole rig pose from frame 0 to frame 80 so that the pose would last that long, 80 frames / 30 frames per second (about 0.26 seconds)
It should work with a single keyframe at 0 but since I do animation I am in the habit of setting starting and ending frames with identical poses.
saved the file as cover pose solo1.blend
For the couple pose (ballet_both.blend) file,
saved a copy as ballet_both-x.blend
In the outliner, selected rig.001 (the female rig),
right clicked and selected delete hierarchy
selected the bone_bone_shape.001
right clicked and selected delete hierarchy
saved the .blend file and closed Blender
Opened the ballet_both.blend again & saved as ballet-both-y
In the outliner, selected rig (the male rig),
right clicked and selected delete hierarchy
selected the bone_bone_shape.001
right clicked and selected delete hierarchy
saved the .blend file and closed Blender
In S4S, Clicked Animation > Clip Pack
named the new pose pack aurorwho-ballet-poses.package and clicked the Clips tab.
named clip 1 "solo"
clicked import and selected the modified solo blend file (cover pose solo1.blend)
clicked add at the right edge of the clips area to add another clip, named it ballet x
clicked import and selected ballet_both-x.blend
clicked add at the right edge of the clips area to add another clip, named it ballet y
clicked import and selected ballet_both-y.blend
saved the package and closed S4S
I tried the poses in game and the solo one worked fine, i.e. my Sim entered the pose looking natural, no sudden move.
The couple pose needed adjustment of the base positions in object mode in blender.
The male actor was moved to position 0, 0, 0 and rotation 0, 0, 0 while the female actor was moved to positoin 0, -0.7, 0 position and rotation 0, 0, 180.
Then, back in pose mode at frame 0, I adjusted the actors to 0, 0, 0 position and rotation (proper idle position) and adjusted them at frame 15 to line up to look at each other etc.
Again, because I am used to animating, and I like to see the idle pose at frame 0, I adjusted the end frame to be 30 (1 second). It makes it easier to ensure the actors start in the right positions.
I pasted a default pose in on each actor for frame 0 and frame 30, and had the actors transition to the desired pose at frame 15
Ideally I should have inserted two keyframes, say at 10 and 20, that are the desired pose. That way you have a section in the middle of the looping animation where they hold still.
Here's a
zip file of the original and changed files. If any of the above isn't clear, please reply asking for clarifications.
To get the actors into position, have them do an interaction, e.g. friendly > hug, and queue up the poses using the pose player.
Here's a 