Programmatic camera control

Control camera position, orientation, and parameters programmatically.

This example demonstrates how to programmatically control client cameras, including smooth animated transitions between viewpoints. Camera control is essential for guided tours, automatic viewpoint switching, or creating cinematic presentations of 3D content.

Key features:

• viser.ViserServer.initial_camera for setting the default camera pose

• viser.CameraHandle.wxyz and viser.CameraHandle.position for setting camera pose

• viser.CameraHandle.near and viser.CameraHandle.far for clipping plane control

• viser.CameraHandle.look_at for orbit center positioning

• viser.ViserServer.atomic() for synchronized camera updates

• Smooth interpolation using SE(3) transformations

The example shows how to create clickable frames that smoothly animate the camera to different viewpoints, and how to use atomic updates to prevent visual artifacts during camera transitions.

Source: examples/03_interaction/04_camera_commands.py

Code

import time

import numpy as np

import viser
import viser.transforms as tf

server = viser.ViserServer()
num_frames = 20

# Set the initial camera pose. This is the pose that new clients will start at,
# and also what "Reset View" will return to.
server.initial_camera.position = (5.0, -5.0, 3.0)
server.initial_camera.look_at = (0.0, 0.0, 0.0)


@server.on_client_connect
def _(client: viser.ClientHandle) -> None:

    client.camera.far = 10.0

    near_slider = client.gui.add_slider(
        "Near", min=0.01, max=10.0, step=0.001, initial_value=client.camera.near
    )
    far_slider = client.gui.add_slider(
        "Far", min=1, max=20.0, step=0.001, initial_value=client.camera.far
    )

    @near_slider.on_update
    def _(_) -> None:
        client.camera.near = near_slider.value

    @far_slider.on_update
    def _(_) -> None:
        client.camera.far = far_slider.value


@server.on_client_connect
def _(client: viser.ClientHandle) -> None:

    rng = np.random.default_rng(0)

    def make_frame(i: int) -> None:
        # Sample a random orientation + position.
        wxyz = rng.normal(size=4)
        wxyz /= np.linalg.norm(wxyz)
        position = rng.uniform(-3.0, 3.0, size=(3,))

        # Create a coordinate frame and label.
        frame = client.scene.add_frame(f"/frame_{i}", wxyz=wxyz, position=position)
        client.scene.add_label(f"/frame_{i}/label", text=f"Frame {i}")

        # Move the camera when we click a frame.
        @frame.on_click
        def _(_):
            T_world_current = tf.SE3.from_rotation_and_translation(
                tf.SO3(client.camera.wxyz), client.camera.position
            )
            T_world_target = tf.SE3.from_rotation_and_translation(
                tf.SO3(frame.wxyz), frame.position
            ) @ tf.SE3.from_translation(np.array([0.0, 0.0, -0.5]))

            T_current_target = T_world_current.inverse() @ T_world_target

            for j in range(20):
                T_world_set = T_world_current @ tf.SE3.exp(
                    T_current_target.log() * j / 19.0
                )

                # We can atomically set the orientation and the position of the camera
                # together to prevent jitter that might happen if one was set before the
                # other.
                with client.atomic():
                    client.camera.wxyz = T_world_set.rotation().wxyz
                    client.camera.position = T_world_set.translation()

                client.flush()  # Optional!
                time.sleep(1.0 / 60.0)

            # Mouse interactions should orbit around the frame origin.
            client.camera.look_at = frame.position

    for i in range(num_frames):
        make_frame(i)


while True:
    time.sleep(1.0)