Articles to read when Blender Python script code doesn't work in 2.80

Good morning Python! Everyone, are you modeling well today!

Speaking of which, when I tried to run Blender with a Python script, I was suffering from a mysterious error. As a result of struggling, it was found that the cause was ** API specification change **. You can think that most of the code currently published on the net (for ≒ 2.79 or earlier) ** does not work just by copying **.

So, for the currently released code, this will work with 2.80! I'm going to publish a modified version of it. After arranging the code before and after the change, I will explain in the form that the changed part is changed like this by referring to the corresponding reference. The key changes are about the same in every code, so it's probably useful for anyone who gets an error in another code.

The people who wrote the code are not bad at all, but there is no help for it because the specifications have changed. It's not that the evolving Blender is bad. If people are suffering when no one is bad ... I'll carry that sin.

First example

Blender x Python makes it easy 3DCG!

It is a script to create the above mesh.

code

original

2.79

import bpy
import math

#reset objects
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete(True)

#world
bpy.context.scene.world.horizon_color=(0.0,0.0,0.0)

#plane_add
for i in range(0,100):
    bpy.ops.mesh.primitive_plane_add(radius = (i*1.1/100),location=(0,0,0),rotation=(math.pi*1/2,math.pi*i*8.2/360,math.pi*i*10/360))

for item in bpy.context.scene.objects:
    if item.type == 'MESH':
        bpy.context.scene.objects.active = bpy.data.objects[item.name]
        bpy.ops.object.modifier_add(type='WIREFRAME')
        bpy.context.object.modifiers['Wireframe'].thickness = 0.0025
        bpy.context.object.modifiers['Wireframe'].use_boundary = True

#lamp add
bpy.ops.object.lamp_add(type='HEMI',location=(0.0,0.0,2.0))

#camera add
bpy.ops.object.camera_add(location=(5.0,0.0,0.0))
bpy.data.objects['Camera'].rotation_euler = (math.pi*1/2, 0, math.pi*1/2)

#render
bpy.context.scene.render.resolution_x = 1000
bpy.context.scene.render.resolution_y = 1000
bpy.context.scene.render.resolution_percentage = 100
bpy.context.scene.camera = bpy.context.object
bpy.context.scene.render.image_settings.file_format = 'PNG'
bpy.data.scenes["Scene"].render.filepath = "tmp/plane.png "
bpy.ops.render.render(write_still=True)

After change

2.80

import bpy
import math

#reset objects
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete(True)

#plane_add
for i in range(0,100):
    bpy.ops.mesh.primitive_plane_add(size = (i*1.1/100),location=(0,0,0),rotation=(math.pi*1/2,math.pi*i*8.2/360,math.pi*i*10/360))

for item in bpy.context.scene.objects:
    if item.type == 'MESH':
        bpy.context.view_layer.objects.active = bpy.data.objects[item.name]
        bpy.ops.object.modifier_add(type='WIREFRAME')
        bpy.context.object.modifiers['Wireframe'].thickness = 0.0025
        bpy.context.object.modifiers['Wireframe'].use_boundary = True

#lamp add
bpy.ops.object.light_add(location=(0.0,0.0,2.0))

#camera add
bpy.ops.object.camera_add(location=(5.0,0.0,0.0))
bpy.data.objects['Camera'].rotation_euler = (math.pi*1/2, 0, math.pi*1/2)

#render
bpy.context.scene.render.resolution_x = 1000
bpy.context.scene.render.resolution_y = 1000
bpy.context.scene.render.resolution_percentage = 100
bpy.context.scene.camera = bpy.context.object
bpy.context.scene.render.image_settings.file_format = 'PNG'
bpy.data.scenes["Scene"].render.filepath = "tmp/plane.png "
bpy.ops.render.render(write_still=True)

changes

2.79

    bpy.ops.mesh.primitive_plane_add(radius = (i*1.1/100),location=(0,0,0),rotation=(math.pi*1/2,math.pi*i*8.2/360,math.pi*i*10/360))

2.80

    bpy.ops.mesh.primitive_plane_add(size = (i*1.1/100),location=(0,0,0),rotation=(math.pi*1/2,math.pi*i*8.2/360,math.pi*i*10/360))

Added plane primitives. Radius indicating the scale is changed to size.

Applicable reference: https://docs.blender.org/api/current/bpy.ops.mesh.html?highlight=primitive%20plane#bpy.ops.mesh.primitive_plane_add

2.79

        bpy.context.scene.objects.active = bpy.data.objects[item.name]

2.80

        bpy.context.view_layer.objects.active = bpy.data.objects[item.name]

Select the active object. The part that was originally bpy.context.scene ～ should be changed to bpy.context.view_layer ～. I'm not sure exactly how to use it because the API of scene remains, but here is the reference [around here](https://docs.blender.org/api/current/bpy.types.Scene" There seems to be no choice but to read .html) and study.

2.79

bpy.ops.object.lamp_add(type='HEMI',location=(0.0,0.0,2.0))

2.80

bpy.ops.object.light_add(location=(0.0,0.0,2.0))

Addition of lamp. Renamed lamp to light. Also, the HEMI (hemisphere) type light has disappeared.

https://docs.blender.org/api/current/bpy.ops.object.html?highlight=light%20add#bpy.ops.object.light_add

#world
bpy.context.scene.world.horizon_color=(0.0,0.0,0.0)

No alternative API was found for this. In GUI

You can change it by operating here. There is an API called bpy.context.scene.world.color, but it doesn't change even if I specify this. This is out of reach. If you want to reproduce it, please change it manually. Excuse me…….

Second example

Introduction to blender python script_Part 01

It is a script that generates the above mesh without using primitives.

Source code

original

2.79

import bpy

#Remove default Cube
def delete_all():
    for item in bpy.context.scene.objects:
        bpy.context.scene.objects.unlink(item)

    for item in bpy.data.objects:
        bpy.data.objects.remove(item)

    for item in bpy.data.meshes:
        bpy.data.meshes.remove(item)

    for item in bpy.data.materials:
        bpy.data.materials.remove(item)

delete_all()

#Define vertex coordinates
coords=[
    (-1.0, -1.0, -1.0),
    ( 1.0, -1.0, -1.0),
    ( 1.0,  1.0, -1.0),
    (-1.0,  1.0, -1.0),
    ( 0.0,  0.0,  1.0)
]

#Define a face using this subscript
#Each face is defined by a sequence of four integers
#Triangular face must have the same first and fourth vertices
faces=[
    (2,1,0,3),
    (0,1,4,0),
    (1,2,4,1),
    (2,3,4,2),
    (3,0,4,3)
]

#Create a new mesh
me          = bpy.data.meshes.new("PyramidMesh")
#Create an object with a mesh
ob          = bpy.data.objects.new("Pyramid", me)
#Place the object at the 3D cursor position
ob.location = bpy.context.scene.cursor_location
#Link objects to scenes
bpy.context.scene.objects.link(ob)
#Fill the vertices, edges, and faces of the mesh
me.from_pydata(coords,[],faces)
#Update mesh with new data
me.update(calc_edges=True)

After change

2.80

import bpy

#Remove default Cube
def delete_all():
    for item in bpy.context.scene.objects:
        bpy.context.scene.collection.objects.unlink(item)

    for item in bpy.data.objects:
        bpy.data.objects.remove(item)

    for item in bpy.data.meshes:
        bpy.data.meshes.remove(item)

    for item in bpy.data.materials:
        bpy.data.materials.remove(item)

delete_all()

#Define vertex coordinates
coords=[
    (-1.0, -1.0, -1.0),
    ( 1.0, -1.0, -1.0),
    ( 1.0,  1.0, -1.0),
    (-1.0,  1.0, -1.0),
    ( 0.0,  0.0,  1.0)
]

#Define a face using this subscript
#Each face is defined by a sequence of four integers
#Triangular face must have the same first and fourth vertices
faces=[
    (2,1,0,3),
    (0,1,4,0),
    (1,2,4,1),
    (2,3,4,2),
    (3,0,4,3)
]

#Create a new mesh
me          = bpy.data.meshes.new("PyramidMesh")
#Create an object with a mesh
ob          = bpy.data.objects.new("Pyramid", me)
#Place the object at the 3D cursor position
ob.location = bpy.context.scene.cursor.location
#Link objects to scenes
bpy.context.scene.collection.objects.link(ob)
#Fill the vertices, edges, and faces of the mesh
me.from_pydata(coords,[],faces)
#Update mesh with new data
me.update(calc_edges=True)

changes

2.79

        bpy.context.scene.objects.unlink(item)

2.80

        bpy.context.scene.collection.objects.unlink(item)

It is a command about the object in the current scene, but since a hierarchy called collection has been added under scene, it is necessary to reflect it. There is also ʻobjects directly under scene, and if that is the case, an error will occur when link or ʻunlink the object, which is the first killing. ʻAttribute Error: Many people may have been cried by the error'bpy_prop_collection'object has no attribute'link'`.

2.79

ob.location = bpy.context.scene.cursor_location

2.80

ob.location = bpy.context.scene.cursor.location

Specify the cursor position. In 2.79 and below, there was an API called curosr_location, but in 2.80, it seems that there is a hierarchical structure with location under cursor.

Applicable reference: https://docs.blender.org/api/current/bpy.types.View3DCursor.html

2.79

bpy.context.scene.objects.link(ob)

2.80

bpy.context.scene.collection.objects.link(ob)

Same as the previous collection story.

Tips for finding a usable API

In this situation, there are too many changes and the information required is still small, so it is necessary to search for an API that can be used by yourself. At such times

Pressing the Ctrl + Space keys on Blender's Python console will bring up a list of candidate commands (if you type halfway, the candidates will be narrowed down accordingly), which may be useful. ..

Let's have a good Blender 2.80 life.