Python for Blender – Batch renaming objects

Software:
Blender 2.8 | Python 3.7

Some useful short Python snippets for batch re-naming objects in Blender:

  1. Remove last 4 characters from selected object names:
    import bpy
    objects = bpy.context.selected_objects
    for o in objects:
        o.name = o.name[:-4]

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  2. Rename all selected objects to a set base name followed by a 3 digit numeric suffix:
    import bpy
    objects = bpy.context.selected_objects
    for (i,o) in enumerate(objects):
         o.name = "some_base_name_{:03d}".format(i)

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  3. Prefix all selected objects name with their Blender data type like renaming “SomeModel” to “MESH_SomeModel” or for example:
    import bpy
    objects = bpy.context.selected_objects
    for (i,o) in enumerate(objects):
         o.name = "{}_{}".format(o.type,o.name)

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* note that when copying and pasting a script from this example, the indentation may not be pasted correctly.

Note:
Blender 2.8 has a robust batch renaming utility that is invoked by pressing Ctrl + F2 so we don’t have to write scripts to do batch renaming of objects:

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Related:

Python for Blender – Accessing Mesh Triangles

Blender Python – Accessing mesh triangles

Software:
Blender 2.81 | Python 3.74

By default, mesh triangles are not accessible to Python in Blender.
When accessing the mesh triangles is needed, they must be calculated first using the ‘calc_loop_triangles’ Mesh object method.
Before the calc_loop_triangle method has been called, the loop_triangles property of the Mesh object will reference a empty collection.
After calling the calc_loop_triangles method, the loop_triangles property will reference a collection of MeshLoopTriangle objects, in which the vertices property will hold an array of 3 integers that are the indices of the triangle vertices.

The following example script creates and places sphere objects at the centers of the cube’s triangles:

import bpy
mesh = bpy.data.objects['Cube'].data
mesh.calc_loop_triangles()
for tri in mesh.loop_triangles:
     tri_center = (mesh.vertices[tri.vertices[0]].co * 0.333) +\
                  (mesh.vertices[tri.vertices[1]].co * 0.333) +\
                  (mesh.vertices[tri.vertices[2]].co * 0.333)
     bpy.ops.mesh.primitive_uv_sphere_add(radius=0.1,
                                          enter_editmode=False, 
                                          location=tri_center)

* note that when copying and pasting a script from this example, the indentation may not be pasted correctly.

Download and example file here

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Related:
Python for Blender – Batch Rename Objects

Blender Python – Make an unselectable object local so it can be selected..

Software:
Blender 2.79

If you happen to link an external object that was made unselectable in the original blend file, You will have no interactive way to make it selectable again, or local, or even delete it from the current blend file.

The good news is that it can easily be done by a very short Python script:

import bpy

obj = bpy.data.objects['the_untouchable_object']
obj.make_local()

It should also be very easy script a loop that will find all those linked objects,
I will post an example when I’ll have a minute to breathe… 😀