Setup

The Setup section holds the marble and the two numbers the course is built from. It sits second, right under Generate.

Marble

A new file shows no marble control here. Generate brings in the built-in glass Hero Marble, and Setup then names it in one line, "Marble: Hero Marble". You never need to pick a marble.

The Marble field appears only when a file points at a marble of its own (a template you built yourself), or when a course has lost its marble; then the Course Editor says "Set the Marble in Setup (above) to activate." and you pick the marble object again. If a template's keys are missing, the field explains it under itself, and Generate refuses with the same sentence: "This file's marble is 'Marble' (Setup > Marble) but its template keys (Key.* + Key Base* pairs) are not in the file. Clear the Marble field in Setup to build from the add-on's own pieces."

In Marble Studio Pro, after a Marble Replacement, the line names the ball you see.

To show a different ball as the marble without changing the course, use Marble Replacement Pro instead.

Rotation Cage

Rotation Cage shows three thin crossing circles around the built-in marble, so you can see it spin. It follows the marble exactly, never renders, cannot be clicked, and hides while another ball is shown as the marble. Untick it to hide it. It only appears for the built-in marble.

Gravity

Gravity (default 24) sets how strongly the marble is pulled down between keys. The time between two notes is fixed by the music, so Gravity changes the shape and size of every arc. The course is built with it when you press Generate, so change it before Generate (or press Next Seed to rebuild).

Recipe: compare two gravities. Note your Seed, change Gravity, type the seed minus one into Seed and press Next Seed: the same layout seed, rebuilt with the new gravity.

Marble Radius

Marble Radius is not a setting you need: it sets where the marble touches the keys, not how big the marble looks, and it is not shown on a new song. It appears only on a song whose value is not the default 0.2, with the line "Marble radius applies at the next Generate", so that song can be set back.