Struggling to make a sphere that rolls using the L stick relative to the camera.

I want to make a simple sphere that will roll according to the left stick direction, relative to what ever way the right stick orients the camera. Elsewhere here I saw a post saying cut a sphere in half and place a microchip in the centre so I try to do that.

Here are my many problems.

In trying to sculpt the sphere, the snap grid weirdly goes off alignment with the floor I made and I have no idea why. Suddenly the grid is at an angle to the floor instead of perpendicular. I have to leave scoped-in mode to reset the grid then enter scoped in mode again.

Because I want to add a tag to the center of the sphere so a follower can hover over dead center, I want to make two spheres, cut them each in half and move the hemispheres together in the shape of a sphere.

I stamp two spheres next to each other with a small gap - this puts me in scoped mode automatically. I use a big cube in subtract mode between them to cut them each in half at the same time so the flat sides of each hemisphere face each other.

I try to move them together but it's like there's an invisible negative space between them - if I move them out of that space parts of the whole spheres become visible again. So I figure out that the subtract tool has left a big invisible cube behind and whenever the spheres leave that space their volume reappears. OK that wasn't obvious so I go to the crop tool.

I undo and get my spheres back again. The crop tool can't be used Cropping each is impossible, it wipes out most of the two spheres.

I look at the cutout tool. This is the opposite of crop so when I choose my cube to cut with, only what is INSIDE the negative space remains. Move the hemispheres beyond this and they're spheres again.

OK so I think, make a sphere, cut it in half using a cube in subtract mode, clone it and join them together. But when I clone the hemisphere, a complete sphere appears instead of the hemisphere I just made.

Hmm. OK, make two spheres. Repeat the subtract via cube thing. I now have two hemispheres , each has a flat side facing right. I go to rotate the right hemisphere so I can bring the two faces together, suddenly it's a complete sphere again???? There's no flip option so I have to manually rotate it but it's now a sphere.


Then I get fed up and write this post trying not to swear.

Why is cutting a sphere in half and joining the parts back together so difficult?