Access skin modifier radius data

Question

With Skin Modifier, we can "weight" a vertex (in Edit Mode) so that the resulting Skin mesh is bigger or smaller - similar to Curve objects which has "Scale Feather" adjustable.

Manually, we can hit Tab, go to Edit Mode, select Vertices, then CtrlA and drag.

However, I would like to be able to do this using Python. Does anyone know anything about it?

Answer 1

Reading and writing these values from Python must happen in Object mode. I added a plane and deleted one vertex, added the skin modifier and decreased the radius of one vertex.

>>> obj = bpy.data.objects['Plane']
>>> for v in obj.data.skin_vertices[0].data:
...     print(v.radius[:])
...     
(0.25, 0.25)
(0.25, 0.25)
(0.08836718648672104, 0.08836718648672104)

Each element in skin_vertices[0].data has radius, use_loose, use_root to read and write. Radii can be any two element iterable (tuple, list).

import bpy

obj = bpy.data.objects['Plane']
for v in obj.data.skin_vertices[0].data:
    v.radius = 0.2, 1.2

I just realized that CtrlA lets you constrain the effect on radius per axis with ShiftX,Y.