Renders a mesh in different view angles and save them as a spritesheet image

obj_mesh_to_spritesheet.py

import trimesh
from PIL import Image
import numpy as np
import io

# If you are running on Apple Silicon, you may need to comment out the 
# following lines as described in this GitHub issue 
# to avoid running into an issue with the trimesh library:
# https://github.com/mikedh/trimesh/issues/2084#issuecomment-1840072858


def render_mesh(mesh, angle, resolution=512):
    """
    Render the mesh with a given view angle and other parameters.

    Parameters
    ----------
    mesh : trimesh.Scene or trimesh.Trimesh
        The mesh to render.
    angle : (3,) float
        Euler angles (pitch, yaw, roll) in radians.
    resolution : int
        Resolution of the rendered image.

    Returns
    -------
    image : PIL.Image
        Rendered image as a PIL Image object.
    """

    # Create the transform matrix from the angle and apply it to the mesh
    transform = trimesh.transformations.euler_matrix(angle[0], angle[1], angle[2])
    mesh.apply_transform(transform)

    # Render the mesh with the camera and transform
    scene = trimesh.Scene([mesh])

    # Set the camera resolution
    scene.camera.resolution = (resolution, resolution)

    #print(scene.camera_transform)

    # Render the image as a PNG byte buffer
    image_data = scene.save_image()
    image = Image.open(io.BytesIO(image_data))
    return image

def create_spritesheet(mesh, angles, resolution=512):
    # Number of images per row/column
    num_images_per_side = int(np.sqrt(len(angles)))
    
    if num_images_per_side ** 2 != len(angles):
        raise ValueError("Spritesheet size must be a perfect square")
    
    # Render each angle
    rendered_images = [render_mesh(mesh, angle, resolution) for angle in angles]
    
    # Calculate the dimensions of the spritesheet
    image_width, image_height = rendered_images[0].size
    spritesheet_width = num_images_per_side * image_width
    spritesheet_height = num_images_per_side * image_height
    
    # Create a new blank spritesheet image
    spritesheet = Image.new('RGB', (spritesheet_width, spritesheet_height))
    
    # Paste each rendered image into the spritesheet
    for i, img in enumerate(rendered_images):
        x = (i % num_images_per_side) * image_width
        y = (i // num_images_per_side) * image_height
        spritesheet.paste(img, (x, y))
    
    return spritesheet

# Load the OBJ mesh
mesh = trimesh.load('humanmalepirateswashbuckler.obj')

# Define angles for rendering
angles = [
    [0, -(np.pi / 2), 0],       # Front
    [np.pi / 2, 0, 0], # Top 90-degree angle
    [np.pi, 0, 0],      # Bottom 180-degree angle
    [np.pi / 2, np.pi / 4, 0], # Side (45 degrees)
    [0, np.pi / 4, 0], 
    [0, np.pi / 4, 0], 
    [0, np.pi / 4, 0], 
    [0, np.pi / 4, 0], 
    [0, np.pi / 4, 0], 
]

# Create the spritesheet
spritesheet = create_spritesheet(mesh, angles)

# Save the spritesheet image
spritesheet.save('mesh_spritesheet.png')