This is one of the most frustrating aspects of pose creation for me, at least. I remember, way back when struggling for the first time to get a pose to look the same in game as in Blender. How I tweaked and tested in game, then went back into Blender to tweak some more. Over and over again till it finally dawned on me, it was the clothes!
Here is the latest example I can show you. Before I do so, please note this is not at all the fault of the clothing creator and in this case, the clothing items by this creator are exactly what storytellers would need for a medical scenario. I’m very thankful these options are out there to use. Also, these poses are not finished. I was still in the first testing stage.
Here is the pose in Blender:
Pay particular attention to the waist, hips and thighs when looking at the in game pics.
The male sim on the right is wearing EA jeans.
Here you see the female sim wearing the EA capris you often see me using for pose pictures. I do so because I know they will keep the pose truest to how it was created. However, EA clothes can change a pose too: