A) rb1957, I think it's the "former" I'm talking. I'm looking at a vehicle that can undergo simultaneous loading. I've created a simple 2D analogy in the attachment just so there in no confusion here. You will see that in case one, I have a moment around Z. And in case two, a force in X acting...
I have a 3D model that experiences different boundary conditions under different conditions (for example when it has +y acceleration the right wheels are constrained; when it has +z acceleration four wheels are constrained). There are six parameters: x, y, z linear acceleration and x, y, z...