You will need to use the Advanced 3D engine in order to render models—the Classic and C4D render engines do not support them.
@grump What AE (Beta) version number are you currently running? There have been a couple of bugs while this work is in progress that prevented model rendering in the Advanced 3D engine, so you may be able to update to the latest (24.1.0.56 as of this post) to see model rendering working again.
how do I change the settings to advanced 3d, when I was still using version 23 I still found mercury 3d, but when I updated it wasn't there anymore, and my 3d objects didn't appear on the work screen.
since updating to version 24 there is no mercury 3d, only Classic 3d and Cinema 4d but in the initial version 23 there was still mercury 3d, but now the old version is no longer there 😞