Yes, spatial reasoning and visualisation seem like two separate unconnected subsystems, even though it seems like they should be related.

I seem able to do the spatial just fine, and the visualisation not at all.

> it's like sensing the position of your arm

Very good, yes it's exactly like this. I know, but I don't need to see. I can explore the model or plan, and know how the result will be, and still don't need to see!