Create 3D monkey head

Introduction:

The following script contains code that performs what I would usually do when starting a new scene (add lights, camera, objects). The script will serve as a starting point for most of my future scripts.

In the future, I might use more complex materials, create animations, or use the built-in physics simulator (for example, rigid body, fluid, smoke).

This is what the script below renders:

The command to run the code is blender --background --python-exit-code 1 --python monkey.py. The code has been tested on Blender 2.81a (released December 5, 2019).

Here are some of my concerns:

• There are quite a few lines which use bpy.ops. bpy.ops should be avoided.
• Clearing all objects in the beginning with select_all and then delete looks like a workaround to me. There might be a way to start a scene without the default cube, light, and camera.

monkey.py

import bpy
import shutil
import os
import time

def add_light(location, light_type='POINT', color=(1.00, 1.00, 1.00), energy=1000.00):
    bpy.ops.object.add(type='LIGHT', location=location)
    obj = bpy.context.object

    obj.data.type = light_type
    obj.data.color = color
    obj.data.energy = energy

def set_smooth(obj, level=None, smooth=True):
    if level:
        modifier = obj.modifiers.new('Subsurf', 'SUBSURF')
        modifier.levels = level
        modifier.render_levels = level

    mesh = obj.data
    for p in mesh.polygons:
        p.use_smooth = smooth

def create_focal_point(location=(0.00, 0.00, 0.00)):
    bpy.ops.mesh.primitive_uv_sphere_add(radius=0.10, location=location)
    focal_point = bpy.context.object
    focal_point.hide_render = True
    return focal_point

def set_focal_point(camera, focal_point):
    bpy.context.view_layer.objects.active = camera
    bpy.ops.object.constraint_add(type='TRACK_TO')
    camera.constraints['Track To'].target = focal_point
    camera.constraints['Track To'].track_axis = 'TRACK_NEGATIVE_Z'
    camera.constraints['Track To'].up_axis = 'UP_Y'

def create_monkey(origin=(0.00, 0.00, 0.00)):
    bpy.ops.mesh.primitive_monkey_add(location=origin)
    obj = bpy.context.object
    return obj

if __name__ == '__main__':
    # Delete all objects
    bpy.ops.object.select_all(action='SELECT')
    bpy.ops.object.delete()

    main_object = create_monkey()

    yellow_rgba = (1.00, 1.00, 0.00, 1.00)

    mat = bpy.data.materials.new(name='yellow')
    mat.use_nodes = True
    mat.diffuse_color = yellow_rgba
    nodes = mat.node_tree.nodes

    nodes.clear()
    node_material_output = nodes.new(type='ShaderNodeOutputMaterial')

    node_diffuse = nodes.new(type='ShaderNodeBsdfDiffuse')
    node_diffuse.name = 'Yellow Diffuse'
    node_diffuse.inputs['Color'].default_value = yellow_rgba

    input = node_material_output.inputs['Surface']
    output = node_diffuse.outputs['BSDF']
    mat.node_tree.links.new(input, output)

    main_object = bpy.context.active_object
    main_object.active_material = mat


    set_smooth(main_object, level=5)

    add_light(location=(5.00, -7.50, 5.00))

    bpy.ops.object.camera_add(location=(0.00, -5.00, 0.00))
    main_camera = bpy.context.object
    bpy.context.scene.camera = main_camera

    focal_point = create_focal_point(main_object.location)
    set_focal_point(main_camera, focal_point)


    bpy.context.scene.render.engine = 'CYCLES'
    bpy.context.scene.cycles.samples = 50

    bpy.context.scene.render.tile_x = 256
    bpy.context.scene.render.tile_y = 256

    bpy.context.scene.render.resolution_x = 600
    bpy.context.scene.render.resolution_y = 600

    bpy.context.scene.render.resolution_percentage = 100

    bpy.context.scene.render.image_settings.compression = 100

    base_filename = time.strftime('%Y %m %d - %H %M %S - ') + os.path.basename(__file__)
    base_filename_no_extension = os.path.splitext(base_filename)[0]
    shutil.copy(__file__, base_filename)

    bpy.ops.wm.save_as_mainfile(filepath=base_filename_no_extension+'.blend')

    bpy.context.scene.render.filepath = base_filename_no_extension+'.png'
    bpy.ops.render.render(write_still=True)