You can modify a mesh without ruining deform keys or weights. Some actions do though, such as Reset
, and it will prompt before doing so. Note if you add vertices, you'll likely need to go to each existing deform key and move the vertex. It's better (for ease of animating, performance, and data size) to avoid deform keys when possible and using weights instead, so you move and key bones to deform the mesh rather than keying all the vertices for the mesh.
There is not a way to remove deformation in setup mode without resetting weights and deform keys. There is not a way to lock a mesh, but it would be unusual to accidentally modify a mesh's vertices.
You can modify a mesh in setup mode by moving vertices to deform it. Or you can use Edit Mesh
with Deformed
checked to move both UVs and vertices without deforming it, or with Deformed
unchecked to move only UVs. None of these actions will remove deform keys or weights.
It's true we have no plans for a scripting API in the editor at this time.
If you have more questions, feel free to ask away!