Stereoscopic camera: how to see objects visible only from the right and left camera

Question

Previously, I've asked this question: How can I see if an object is inside the volume rendering of the camera? and I had found the solution thanks to this post: Does Camera.view_frame() return the correct size of near clip plane?

The line code x, y, z = world_to_camera_view(sce, cam, mat * v.co) is perfect for found the objects are visible from the central camera but it excludes items that are only visible from a single camera (camera L or R). I want to find the objects visible only from the right camera and objects visible only from the left camera.

A possible solution would be:

1. Delete stereoscopy
2. Move the camera to the right of intercular distance / 2
3. Incline the camera to the z-axis of angle of convergence (easy calculation)
4. Check the visible item with world_to_camera_view
5. Repeat for simulate the left camera (move to right and rotate z -angle)
6. Set True the stereoscopy

But how to eliminate the stereoscopy and have a camera equal to that of the left and right?

---

I solved my issue by following the steps I listed. Now I have this problem:

If I place the camera on the right of a value (even higher) and then use world_to_camera_view the result I get is the same. That tells me that the camera always sees the same objects.

Code

import bpy
from bpy_extras.object_utils import world_to_camera_view

context = bpy.context
scene = bpy.context.scene
scene.update

def checkIfIsInCameraView(cam, obj):
    for v in obj.data.vertices:
        x, y, z = world_to_camera_view(context.scene, cam, obj.matrix_world * v.co)
        if (0.0 <= x <= 1.0 and 0.0 <= y <= 1.0):
            return True

    return False

#set off stereo
scene.render.use_multiview = False

#creo nuova camera per simulare camera laterale
cameraNormal = scene.camera

#change camera position
cameraNormal.location.x = cameraNormal.location.x - 50.0

for obj in scene.objects:
    if obj.type == 'MESH':
        #print if in camera view
        if checkIfIsInCameraView(cameraNormal, obj):
            print(obj)

#change camera position
cameraNormal.location.x = cameraNormal.location.x + 100.0

for obj in scene.objects:
    if obj.type == 'MESH':
        #print if in camera view
        if checkIfIsInCameraView(cameraNormal, obj):
            print(obj)

#set on stereo
scene.render.use_multiview = True
scene.update

Some tips?

Answer 1

Sometimes, you need to use scene.update() once you've modified some properties (location, rotation) of the objects. When the scene is updated, you can use the new values. You forgot the parentheses after the function call :)