Quote Originally Posted by Knaight View Post
Gravity points generally towards the center, particularly on the outer edge. This isn't a space station where gravity due to mass can basically be neglected, and assuming that the same behavior holds doesn't work.
Correct. Assuming the object as a whole is as massive as a world. In which case the inclination of the upper plane, (thick in the center, thin at the edges,) counters the inward pull, allowing the observer to feel that 'down' is a horizontal plane beneath her feet. By far the biggest pull on an individual on its surface would be from the thickness of the plate beneath her and her distance from the center.

On this world the inner wall required to prevent all of the air from pouring into the central sun would have to be at least 300 miles high, but it wouldn't need an outer wall because gravity slopes uphill more as the viewer approaches the outer rim. With no centripetal force one could stand on the rim and down would be in the direction of the sun. This region would be stripped of atmosphere on my spaceship-world, but even on an unmoving world, air here must be thin or else very thick at the hub because atmospheres make balls no matter the shape of the object that attracts it. (My spaceship world would need an outer rim wall because half its atmosphere was blown away when the massive bombs that got the world moving went off and the rest is being squished onto the surface by the sun-drive's thrust which gives the average observer the feeling of being on a planetary surface under normal gravity, so long as he remains topside.