In Python how can I name the active selection Low Poly, join the others and name them High Poly?

Question

In a Blender 2.8 script I want to bake multiple high poly objects on one low poly.

I want to create a script in Blender 2.8 that bakes in selected to active mode. The active selection must be named "low poly", the other selections are joined and are named "high poly".

Worth noting: https://blender.stackexchange.com/questions/2848/why-avoid-bpy-ops — Ray Mairlot, Jan 26 '19 at 18:57
Could you please make this a bit clearer. Maybe with a 3 or 4 object example. — batFINGER, Mar 26 '19 at 08:36
I'd like to help but I don't get what you want. What's your situation exactly? And what's your actual goal? Just baking all and join them? Why a random selection when the low-res geometry is already prepared? — brockmann, Apr 01 '19 at 11:24

score 2 · Accepted Answer · edited Jan 29 '24 at 19:27

I hope that's what you're looking for.

Select the low-poly object and run the script to add a <Name>_LowPoly suffix to the objects name in the first place, join all other mesh objects of the collection and rename the result to <Name>_HighPoly:

import bpy
suffix = "_LowPoly"
act_obj = bpy.context.view_layer.objects.active
Append the suffix to the active object
if suffix not in act_obj.name:
    act_obj.name = act_obj.name + suffix
Get the collection of the active object
obj_coll = act_obj.users_collection[0]
Create an empty list
high_poly_objects = []
Append all mesh objects (of the collection) to the list
for ob in obj_coll.objects:

    if not "Low" in ob.name and ob.type == 'MESH':
        high_poly_objects.append(ob)
Deselect all objects
bpy.ops.object.select_all(action='DESELECT')
Select all High-Poly objects to call the join operator
for ob in high_poly_objects:
    ob.select_set(True)
    bpy.context.view_layer.objects.active = ob
Join all objects selected before
bpy.ops.object.join()
Get the object in context and re-name it
if "High" not in bpy.context.object.name:
    bpy.context.object.name += "_HighPoly"
Optional -> Invert the selection for fun
for ob in obj_coll.objects:
    if "Low" in ob.name:
        bpy.context.view_layer.objects.active = ob
        ob.select_set(True)
    else:
        ob.select_set(False)

You can also override the context of bpy.ops.object.join() to avoid any viewport selection changes. Select all objects, make the low-poly object the 'Active Object' and run the script:

import bpy
hp_suffix = "HIPOLY"
lp_suffix = "LOWPOLY"
C = bpy.context
scene = C.scene
ob_active = C.active_object
if not ob_active.name.endswith(lp_suffix):
    ob_active.name += "_{}".format(lp_suffix)
obs = []
for ob in C.selected_editable_objects:
    if ob.type == 'MESH' and ob != ob_active:
        obs.append(ob)
if len(obs) > 1:
    c = {}
    c["object"] = c["active_object"] = obs[0]
    c["selected_objects"] = c["selected_editable_objects"] = obs
# Blender 3.2+
with C.temp_override(c):
    bpy.ops.object.join()

# Blender 2.8+
#bpy.ops.object.join(c)


if not obs[0].name.endswith(hp_suffix):
    obs[0].name += "_{}".format(hp_suffix)

No problem, glad it is working @DanylBekhoucha Let me know if you need something else. — brockmann, Apr 02 '19 at 09:03
Looks super sweet, thanks for adding how to override the context @p2or. — brockmann, Apr 02 '19 at 10:46
In the script of p2or, the line "if len(obs) > 1:" must be set to 0 otherwise we need 3 objects selected minimum (so 2 high polys) to add the suffix "_HIPOLY". — Danyl Bekhoucha, Apr 02 '19 at 12:20

In Python how can I name the active selection Low Poly, join the others and name them High Poly?

1 Answers1

Append the suffix to the active object

Get the collection of the active object

Create an empty list

Append all mesh objects (of the collection) to the list

Deselect all objects

Select all High-Poly objects to call the join operator

Join all objects selected before

Get the object in context and re-name it

Optional -> Invert the selection for fun

Linked