LiveQuad — For Blender® 4.5+ and 5.2+
The Base changed after I drew on it
Press Reproject: every vertex of the Target snaps back onto the Base.
My model is made of several meshes
Set Base to Collection and pick the collection that holds them.
The new topology sinks into the Base
Raise Surface Offset. Big polygons on a curved Base cut through it: add loops or relax to follow the shape.