A combined camera allows you to easily switch between a perspective camera and an orthographic camera.
from pythreejs import *
from IPython.display import display
mesh1 = Mesh(SphereBufferGeometry(20, 16, 16), MeshPhysicalMaterial(color='red'), position=[-20, 0, 0])
mesh2 = Mesh(SphereBufferGeometry(20, 16, 16), MeshPhysicalMaterial(color='green'), position=[20, 0, 0])
view_width = 600
view_height = 400
camera = CombinedCamera(position=[0, 0, 60], width=view_width, height=view_height)
key_light = PointLight(position=[-100, 100, 100])
ambient_light = AmbientLight(intensity=0.4)
scene = Scene(children=[mesh1, mesh2, key_light, ambient_light, camera])
renderer = Renderer(scene=scene, camera=camera, controls=[OrbitControls(controlling=camera)],
width=view_width, height=view_height)
display(renderer)
camera.mode = 'orthographic'
camera.mode = 'perspective'