[Feature request] Asteroid editing

[megamanzteam]

This is for existing asteroids or one generated by se toolkit (after realizing multi materials was available). I want to be able to change the percentage of the content or add additional materials.

So for example I want to change stone to be 30% from the picture. Also maybe add Ice by 20% and have the percents dynamically update?

If this has been implemented already I have no idea how to do it. If not, would it be rather easy or will there be issues with generating or re-generating the asteroid?

Thank you for looking at this.