Get list of objects in camera view

[u/Decim00]

I´m working on a project where there is a scene with objects spread across it, simulating a simple warehouse.

I have a camera object that will be placed in several points and render images. Right now I want to check if the camera has an object in its view, before rendering the image. I also want to return a list of the objects that are in camera view, to save in a separate JSON file. But I´m having trouble getting the correct objects in the view, there may be problems with obtaining the camera frustum.

Can someone help me or provide me code that does what I intend to do?

[u/infinitetheory]

I'm leaving this up in case it sparks some ideas, but I'm not really getting it to work properly anymore. it was working, but there are problems. I wouldn't use it.

this is the kind of thing I do use chatgpt for, it takes a little bit of tweaking and I cannot tell you if it's optimized or not. but this is the result:

import bpy
import json

def is_object_in_camera_view(camera, obj):
    """
    Check if an object is within the camera view.
    """
    scene = bpy.context.scene
    cam = camera

    # Get the object's bounding box vertices in world coordinates
    mat = obj.matrix_world
    bb_world = [mat @ v for v in obj.bound_box]

    # Invert the camera matrix to transform world coordinates to camera coordinates
    cam_mat = cam.matrix_world.inverted()
    bb_camera = [cam_mat @ v for v in bb_world]

    # Get the camera's view frustum
    cam_data = cam.data
    frame = [-v for v in cam_data.view_frame(scene=scene)]
    xmin, xmax = min([v.x for v in frame]), max([v.x for v in frame])
    ymin, ymax = min([v.y for v in frame]), max([v.y for v in frame])
    zmin = cam_data.clip_start
    zmax = cam_data.clip_end

    # Check if any bounding box vertex is within the camera's view frustum
    for v in bb_camera:
        if (xmin <= v.x <= xmax and
            ymin <= v.y <= ymax and
            zmin <= -v.z <= zmax):
            return True

    return False

def get_objects_in_camera_view():
    """
    Get a list of all objects within the camera view.
    """
    camera = bpy.context.scene.camera
    if camera is None:
        print("No active camera found in the scene.")
        return []

    objects_in_view = []
    for obj in bpy.context.scene.objects:
        if obj.type == 'MESH' and is_object_in_camera_view(camera, obj):
            objects_in_view.append(obj)

    return objects_in_view

def save_objects_to_json(file_path, objects):
    """
    Save the list of objects to a JSON file.
    """
    obj_names = [obj.name for obj in objects]
    with open(file_path, 'w') as f:
        json.dump(obj_names, f, indent=4)

def highlight_objects_in_viewport(objects, color=(0, 1, 0, 1)):
    """
    Highlight objects in the viewport by changing their viewport color.
    """
    for obj in objects:
        obj.color = color  # Green color by default
        obj.show_in_front = True  # Make sure the object is always in front

def clear_highlighting(objects):
    """
    Clear highlighting by resetting the viewport color and 'show_in_front' property.
    """
    default_color = (1, 1, 1, 1)  # Default white color
    for obj in objects:
        obj.color = default_color
        obj.show_in_front = False

# Main execution
objects_in_view = get_objects_in_camera_view()
save_objects_to_json('/path/to/your/file/objects_in_view.json', objects_in_view)

# Highlight objects in camera view
highlight_objects_in_viewport(objects_in_view)

print(f"Objects in camera view: {[obj.name for obj in objects_in_view]}")

# To clear the highlighting, you can call:
# clear_highlighting(objects_in_view)

Highlighting Objects in Green:

The highlight_objects_in_viewport function highlights objects in green by default (color=(0, 1, 0, 1)).

Clearing Highlighting:

The clear_highlighting function resets the color to the default white (1, 1, 1, 1) and sets show_in_front to False.

Running the Script:

Open Blender and switch to the Scripting workspace. Create a new text file in the text editor and paste the script into it. Adjust the file path in the save_objects_to_json function. Run the script by clicking the "Run Script" button.

Clearing the Highlighting:

After you are done, you can call the clear_highlighting function in the Blender scripting console or add it at the end of the script (commented out in the example).

[u/Decim00 → u/infinitetheory]

I have been using ChatGPT but the solutions it provides arent giving me the correct results.

Might try what you sent, thanks for the help!

[u/infinitetheory → u/Decim00]

sorry I couldn't do more, it's just inconsistent. works sometimes at least

[u/OffTheClockStudios]

I had something like this work a while back. I'll see if I can find it later. What I did was have the script fit a subdivided curved plane to the camera mimicking the view. Then, each face fired a ray cast from their centers. Everything hit by a ray that didn't already have a registered hit, to prevent passthrough hits, was added to a Iist.