Show camera as mesh

[wkentaro]

#!/usr/bin/env python

import numpy as np
import trimesh
import trimesh.transformations as tf


trimesh.util.attach_to_log(level='WARNING')


def get_homography_rpy(roll, pitch, yaw, distance, center):
    translation = tf.translation_matrix(center)
    translation[2][3] += distance  # z from center
    rotation = (
        tf.rotation_matrix(roll, [1, 0, 0], point=center) @
        tf.rotation_matrix(pitch, [0, 1, 0], point=center) @
        tf.rotation_matrix(yaw, [0, 0, 1], point=center)
    )
    transform = translation @ rotation
    return transform


def get_homography_lookat(eye, lookat):
    # both are positions
    assert len(eye) == 3
    assert len(lookat) == 3


if __name__ == '__main__':
    extents = (0.5, 0.5, 0.5)
    box = trimesh.creation.box(extents)
    box.visual.face_colors = [255, 0, 0, 127]

    scene = trimesh.Scene()
    scene.add_geometry(box, node_name='box')

    scene.add_geometry(trimesh.creation.axis())

    roll, pitch, yaw = 0, 0, np.deg2rad(45)
    distance = 0.9
    center = (0, 0, 0)
    transform = get_homography_rpy(roll, pitch, yaw, distance, center)
    print('Using RPY (Red)')
    print('Distance:', distance)
    print('RPY:', (roll, pitch, yaw))

    scene_camera = scene.copy()
    camera = trimesh.scene.Camera(
        resolution=(320, 240),
        fov=(60, 45),
        transform=transform
    )
    scene_camera.set_camera(camera=camera)
    scene_camera.show(start_loop=False)

    # this transform is necessary to get correct image
    transform = transform @ tf.rotation_matrix(np.deg2rad(-180), [1, 0, 0])
    camera.transform = transform
    scene.add_geometry(camera.as_meshes())
    scene.show()

[wkentaro]

# this transform is necessary to get correct image
transform = transform @ tf.rotation_matrix(np.deg2rad(-180), [1, 0, 0])

Actually this is necessary because z axis is other way around in trimesh.

[coveralls]

Coverage increased (+0.05%) to 83.934% when pulling 29ae6ce on wkentaro:camera_mesh into 9c27e7d on mikedh:master.

[mikedh]

Nice! I think this probably makes most sense intrimesh.creation, as camera_marker or something:

def camera_marker(camera, marker_height):
    """
    Create a visual marker for a camera object, including an axis marker and FOV indicator. 

    Parameters
    ---------------
    camera : trimesh.scene.Camera
        Camera object with FOV and transform defined
    marker_height : float
        How far along the camera Z should FOV indicators be
 
    Returns
    ------------
    meshes : list
       Contains Trimesh and Path3D objects which can be visualized
    """

• imports should probably be relative (i.e. from .path import load_path)
• could you add a docstring?
• I think focal_length is a little overloaded; I changed it to "marker_height" or something. Probably also want to make origin radius always relative to this.
• Is the PointCloud necessary? I don't see them in your screenshot.

[wkentaro]

Updated example:

#!/usr/bin/env python

import numpy as np
import trimesh
import trimesh.transformations as tf


trimesh.util.attach_to_log(level='WARNING')


def get_homography_rpy(roll, pitch, yaw, distance, center):
    translation = tf.translation_matrix(center)
    translation[2][3] += distance  # z from center
    rotation = (
        tf.rotation_matrix(roll, [1, 0, 0], point=center) @
        tf.rotation_matrix(pitch, [0, 1, 0], point=center) @
        tf.rotation_matrix(yaw, [0, 0, 1], point=center)
    )
    transform = translation @ rotation
    return transform


def get_homography_lookat(eye, lookat):
    # both are positions
    assert len(eye) == 3
    assert len(lookat) == 3


if __name__ == '__main__':
    extents = (0.5, 0.5, 0.5)
    box = trimesh.creation.box(extents)
    box.visual.face_colors = [255, 0, 0, 127]

    scene = trimesh.Scene()
    scene.add_geometry(box, node_name='box')

    scene.add_geometry(trimesh.creation.axis())

    roll, pitch, yaw = 0, 0, np.deg2rad(45)
    distance = 0.9
    center = (0, 0, 0)
    transform = get_homography_rpy(roll, pitch, yaw, distance, center)
    print('Using RPY (Red)')
    print('Distance:', distance)
    print('RPY:', (roll, pitch, yaw))

    scene_camera = scene.copy()
    camera = trimesh.scene.Camera(
        resolution=(320, 240),
        fov=(60, 45),
        transform=transform
    )
    scene_camera.set_camera(camera=camera)
    scene_camera.show(start_loop=False)

    # this transform is necessary to get correct image
    transform = transform @ tf.rotation_matrix(np.deg2rad(-180), [1, 0, 0])
    camera.transform = transform
    mesh = trimesh.creation.camera_marker(camera=camera)
    scene.add_geometry(mesh)
    scene.show()

[wkentaro]

I addressed all of your comments. Could you review again?

[mikedh]

Awesome! Merged to master in ef90ebc and should release as soon as the build finishes.

I made some minor changes, the main thing was moving the import into the function and a try/except ImportError block to keep path a soft dependency. I also changed the load_path to a single call by stacking into one array of line segments.

Thanks for the PR's!! It's great to get your work into the master branch and releases 😄

[wkentaro]

Thanks for your help!