PYTHON AND BLENDER SCRIPTING

a work in progress

GISTS

• the real basics: run if main

    if __name__ == "__main__":
        main()

• declare filepath for render: bpy.data.scenes[0].render.filepath

• basic launch command structure: blender $TEMPLATE --background --python $SCRIPT

• don't forget to setup blender alias in .zshrc or .bash_profile. alias blender='/Applications/Blender.app/Contents/MacOS/Blender'

• get home directory

    import os
  
    homeDirectory = os.getenv("HOME")

LAUNCH SCRIPT TEMPLATE

#! /usr/bin/env zsh

BLENDER_WORK_FOLDER="$HOME/Desktop/project-blender-py/blender-work"
RENDER_FOLDER="$HOME/Desktop/project-blender-py/renders"
TEMPLATE_FOLDER="$HOME/Desktop/project-blender-py/blender-templates"
PYTHON_SCRIPT="$HOME/Desktop/project-blender-py/bpy-scripts/projects/bar-graphs/launch.py"

CURRENT_TIME=$(date "+%Y%m%d%H%M%S")
OUTPUT_PATH="$BLENDER_WORK_FOLDER/output-$CURRENT_TIME.blend"
RENDER_PATH="$RENDER_FOLDER/scripted/test-$CURRENT_TIME.png"
TEMPLATE="$TEMPLATE_FOLDER/just-a-cam.blend"
DATE_FOR_TEXT=$(date "+%Y%m%d")
TIME_FOR_TEXT=$(date "+%H:%M:%S")

echo "the date for text is being sent in as $DATE_FOR_TEXT"

# blender $TEMPLATE --background --python $PYTHON_SCRIPT  --SHOOT_DATE="$DATE_FOR_TEXT" --SHOOT_TIME="$TIME_FOR_TEXT" --OUTPUT_PATH="$OUTPUT_PATH" --RENDER_PATH="$RENDER_PATH"
# open "$OUTPUT_PATH" -a blender
# open $RENDER_PATH -a Preview
/Applications/Blender.app/Contents/MacOS/blender $TEMPLATE --python $PYTHON_SCRIPT --  --SHOOT_DATE="$DATE_FOR_TEXT" --SHOOT_TIME="$TIME_FOR_TEXT" --OUTPUT_PATH="$OUTPUT_PATH" --RENDER_PATH="$RENDER_PATH"

MORE GISTS

• round to number

  def round_to(n, decimals=3):
    multiplier = 10 ** decimals
    return round(n*multiplier) / multiplier

• get radius

  def getRadius(pQuant):
    print(f'getting radius for value {pQuant}')
    radius = round_half_up((pQuant*3./(4.*3.14159))**(1./3))
    return radius

• append object

  bpy.ops.wm.append(directory=f'{homeDirectory}/Desktop/_blender/prefabs/pumpkin-template.blend\\Object\\', filename="Pumpkin")

• append structure

  bpy.ops.wm.append(directory={FILEPATH}, filename={OBJECT_NAME})

• change location and rotation of object with known name

  bpy.data.objects["Plane"].location[0]=-120
  bpy.data.objects["Plane"].rotation_euler[2]=-1.18

• open json file as data

  with open(f'{homeDirectory}/Desktop/_blender/data/pumpkin-data.json') as data_file:
    data = json.load(data_file)

• grab template object and hide in render and viewport

  pumpkinTemplate = bpy.data.objects["Pumpkin"]
  pumpkinTemplate.hide_render = True
  pumpkinTemplate.hide_viewport = True

• example of creating series of text objects with loop

  for i, country in enumerate(data):
    xVal+=(country["radius"])
    print(f'working on {country["name"]}, which produced {country["pumpkins"]} pumpkins.')
    bpy.ops.object.text_add(enter_editmode=False, location=(0, 0, 0))
    bpy.context.active_object.name=(f'{country["name"]}-text')
    bpy.context.active_object.data.body=f'{country["name"]}\n{country["pumpkins"]}'
    bpy.context.active_object.data.size=15
    bpy.context.active_object.data.align_x='CENTER'
    bpy.context.active_object.data.extrude=3
    bpy.context.active_object.data.bevel_depth=.15
    bpy.context.active_object.location[0] = xVal
    bpy.context.active_object.location[1] = -34
    bpy.context.active_object.rotation_euler[0] = 1.5708
    bpy.ops.object.add_named(linked=False, name='Pumpkin')
    bpy.context.active_object.name = f'{country["name"]}-pumpkin'
    print(f'when we do the radius, it will be {getRadius(country["pumpkins"])}')
    bpy.context.active_object.location[0] = xVal
    bpy.context.active_object.location[1] = 0
    bpy.context.active_object.location[2] = country["radius"]
    bpy.context.active_object.scale = [country["radius"],country["radius"],country["radius"]]
    bpy.context.object.hide_render = False
    bpy.context.object.hide_viewport = False
    xVal+=(country["radius"]+10)
  

* save file as

bpy.ops.wm.save_as_mainfile(filepath=f'{homeDirectory}/Desktop/output.blend')

* parse command line arguments
    ```
    import argparse

    def get_arguments():
        argv = sys.argv
        usage_text = (
                "Run blender in background mode with this script:"
                "  blender --background --python " + __file__ + " -- [options]"
            )
        if "--" not in argv:
            argv = []  # as if no args are passed
        else:
            argv = argv[argv.index("--") + 1:]  # get all args after "--"
        parser = argparse.ArgumentParser(description=usage_text)
        parser.add_argument(
            "-t", "--text", dest="text", type=str, required=False,
            help="This text will be used to render an image",
        )
        parser.add_argument(
            "-o", "--OUTPUT_PATH", dest="OUTPUT_PATH", type=str, required=True,
            help="This text will be used to define the output path",
        )
        parser.add_argument(
            "--RENDER_PATH", dest="RENDER_PATH", type=str, required=True,
            help="This text will be used to define the render path",
        )
        parser.add_argument(
            "--SHOOT_DATE", dest="SHOOT_DATE", type=str, required=True,
            help="This text will be used to define the shoot date string",
        )
        parser.add_argument(
            "--SHOOT_TIME", dest="SHOOT_TIME", type=str, required=True,
            help="This text will be used to define the shoot time string",
        )
        args = parser.parse_args(argv)
        return args

    theArgs = get_arguments()
    print(f'the shoot date is {theArgs.SHOOT_DATE}')
    ```

* add text from arguments
    ```
    bpy.ops.object.text_add(enter_editmode=False, location=(0, 0, 0))
        if the_args.text:
            bpy.context.active_object.name=(f'text test')
            print(the_args.text)
            bpy.context.active_object.data.body=f'{the_args.text}'
        elif the_args.SHOOT_DATE:
            bpy.context.active_object.name=(f'shoot-date')
            bpy.context.active_object.data.body=f'{the_args.SHOOT_DATE}'
        else:
            print("there is no text value to add")
    ```
* typical text object manipulation
    ```
    bpy.ops.object.text_add(enter_editmode=False, location=(0, 0, 0))
    bpy.context.active_object.name=(f'shoot-time')
    bpy.context.active_object.data.body=f'{the_args.SHOOT_TIME}'
    bpy.context.active_object.data.size=.2
    bpy.context.active_object.data.align_x='CENTER'
    bpy.context.active_object.data.extrude=.04
    bpy.context.active_object.data.bevel_depth=.0007
    bpy.context.active_object.location[0] = 0
    bpy.context.active_object.location[1] = -1
    bpy.context.active_object.location[2] = -.29
    bpy.context.active_object.rotation_euler[0] = 1.5708
    ```
* add a plane and a light
    ```
    bpy.ops.mesh.primitive_plane_add(size=10, location=(0,0,-.3))
    bpy.ops.object.light_add(type='SPOT', radius=1, location=(0, -4, 15))
    bpy.context.active_object.data.energy=5000
    ```
* render
    ```
    print("rendering")
    sceneKey = bpy.data.scenes.keys()[0]
    print(f'sceneKey = {sceneKey}')
    for obj in bpy.data.objects:
        if ( obj.type == 'CAMERA' ):
            print(f'Rendering scene: {sceneKey}. Camera name: {obj.name}')
            bpy.data.scenes[sceneKey].camera = obj
            bpy.data.scenes[sceneKey].render.engine = 'BLENDER_EEVEE'
            bpy.data.scenes[sceneKey].render.resolution_x = 1920
            bpy.data.scenes[sceneKey].render.resolution_y = 1080
            bpy.data.scenes[sceneKey].render.filepath = the_args.RENDER_PATH
            bpy.ops.render.render(write_still=True, scene=sceneKey)
    ```

* render all cams

sceneKey = bpy.data.scenes.keys()[0] c=1 for obj in bpy.data.objects: if ( obj.type =='CAMERA'): print("Rendering scene["+sceneKey+"] with Camera["+obj.name+"]") bpy.data.scenes[sceneKey].camera = obj #bpy.data.scenes[sceneKey].render.file_format = 'JPEG' bpy.data.scenes[sceneKey].render.filepath = f'{RENDER_FOLDER}/camera_' + str(c) + '_' # Render Scene and store the scene bpy.ops.render.render( animation=True ) c = c + 1 print('Done!')

* create text object with font

def createTextObject(textContent, size, rotation, extrusion, alignment): print("creating text with textContent=" + textContent) bpy.ops.object.text_add(enter_editmode=False, align='WORLD', location=(0, 0, 0)) textObject = bpy.context.active_object textObject.data.body = str(textContent) textObject.rotation_euler[0] = radians(rotation) textObject.data.extrude = extrusion textObject.data.size=size textObject.name=textContent textObject.data.align_x = alignment return textObject

def quickText(textContent): bpy.ops.object.text_add(enter_editmode=False, align='WORLD', location=(0, 0, 0)) textObject = bpy.context.active_object textObject.data.body = str(textContent) textObject.rotation_euler[0] = radians(90) textObject.data.extrude = 0.1 textObject.data.align_x = 'CENTER' return textObject

textObject = createTextObject(str(result), 3, 90, 0.2, 'CENTER') textObject.location[0]=result

greeting = quickText("hello Conrad") greeting.location[2]=4

change the font

textObject.data.font=bpy.data.fonts.load("/System/Library/Fonts/Avenir Next.ttc") greeting.data.font=bpy.data.fonts.load("/Users/mk/Library/Fonts/Forum-Regular.ttf")

or

SFHeavy = bpy.data.fonts.load("/Library/Fonts/SF-Pro-Display-Heavy.otf") bigLetter = createTextObject("Z", 20, 90, 1.0, 'CENTER') bigLetter.location[1]=10 bigLetter.data.font=SFHeavy

* light area

def lightTheSpot(spotToLight): bpy.ops.object.light_add(type='AREA', radius=1, align='WORLD', location=(0, 0, 0)) light = bpy.context.active_object light.location[2] = 3 light.location[0] = result light.data.energy = 500

lightTheSpot(result)

### MINECRAFT BLOCK ATTEMPT 4 ###

import bpy bpy.ops.object.select_all(action='SELECT') bpy.ops.object.delete(use_global=False)

grassPathTop="/Users/mk/Desktop/ck-blender-minecraft-project/textures/Minecraft-textures/assets/minecraft/textures/block/grass_path_top.png" grassPathSide="/Users/mk/Desktop/ck-blender-minecraft-project/textures/Minecraft-textures/assets/minecraft/textures/block/grass_block_side.png"

class Block: def init(self, name, side, top, bottom): bpy.ops.mesh.primitive_cube_add() self.object = bpy.context.active_object self.name = name self.side = side if top: self.top = top else: self.top = self.side if bottom: self.bottom = bottom else: self.bottom = self.side self.sideImage = bpy.data.images.load(self.side) self.sideTex = bpy.data.textures.new(self.side, 'IMAGE') self.sideTex.image = self.sideImage self.sideMaterial = bpy.data.materials.new(name=f"{name}-side-material") self.topMaterial = bpy.data.materials.new(name=f"{name}-top-material") self.bottomMaterial = bpy.data.materials.new(name=f"{name}-bottom-material") self.sideMaterial.use_nodes = True self.topMaterial.use_nodes = True self.bottomMaterial.use_nodes = True bsdf = self.sideMaterial.node_tree.nodes["Principled BSDF"] texImage = self.sideMaterial.node_tree.nodes.new('ShaderNodeTexImage') texImage.image = bpy.data.images.load(self.side) self.sideMaterial.node_tree.links.new(bsdf.inputs['Base Color'], texImage.outputs['Color']) self.sideMaterial.node_tree.nodes["Image Texture"].interpolation = 'Closest'

    if self.object.data.materials:
        self.object.data.materials[0] = self.sideMaterial
    else:
        self.object.data.materials.append(self.sideMaterial)
    self.object.data.materials.append(self.topMaterial)
    self.object.data.materials.append(self.bottomMaterial)

# # #def set_UV_editor_texture(mesh):

""" set the image for the face.tex layer on all the faces

so we have a rough idea of what the mesh will look like

in the 3D view's Texture render mode"""

# load the mesh data into a bmesh object

bm = bmesh.new()

bm.from_mesh(mesh)

bm.faces.ensure_lookup_table()

# Get the "tex" layer for the first UV map

# If you don't already have a UV map, why are you even calling this function?

tex_layer = bm.faces.layers.tex[mesh.uv_layers[0].name]

for i in range(len(bm.faces)):

# figure out which material this face uses

mi = bm.faces[i].material_index

mat = mesh.materials[mi]

# Assume that we want to use the image from the first texture slot;

# and assume that the material has a texture in that first slot;

# and assume that the texture is an image texture instead of a procedural texture.

# if any of several assumptions are wrong, this will explode

img = mat.texture_slots[0].texture.image

bm.faces[i][tex_layer].image = img

# copy the modified data into the mesh

bm.to_mesh(mesh)

#fname = "/var/tmp/blender/mohawk-seal0001.png" #obj = bpy.context.active_object #mat = material_for_texture(fname) #if len(obj.data.materials)<1:

obj.data.materials.append(mat)

#else:

obj.data.materials[0] = mat

#set_UV_editor_texture(obj.data)

blockOne = Block("grass", grassPathSide, grassPathTop, None) #blockTwo = Block("iron", "C:/Users/ll/Desktop/_blender/block/iron_block.png", None, None) blockOne.object.location[2] = 3

### NEW OBJECT FROM TEMPLATE ###

homeDirectory = os.getenv("HOME") blocksFolder = "/Users/mk/Desktop/ck-blender-minecraft-project/blender/blocks"

class BlockTemplate(name): def init: # get rid of any conflicting objects in scene self.filepath = f"{blocksFolder}/{name}.blend\Object\" self.name = name if bpy.data.objects[self.name]: bpy.data.objects[self.name].select_set(True) bpy.ops.object.delete() bpy.ops.wm.append(directory=self.filePath, filename=self.name) #self.object=bpy.context.active_object self.object=bpy.data.objects[self.name] self.object.hide_render = True self.object.hide_viewport = True

class Block(template, index): def init: bpy.ops.object.add_named(linked=False, name=template) self.object = bpy.context.active_object .name = f'{country["name"]}-pumpkin' print(f'when we do the radius, it will be {getRadius(country["pumpkins"])}') bpy.context.active_object.location[0] = xVal bpy.context.active_object.location[1] = 0 bpy.context.active_object.location[2] = country["radius"] bpy.context.active_object.scale = [country["radius"],country["radius"],country["radius"]] bpy.context.object.hide_render = False bpy.context.object.hide_viewport = False xVal+=(country["radius"]+10)