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pythonopenglvisualizationpoint-cloudsopen3d

Can I get the viewing angle of a pointcloud using SceneWidget in Open3D?

I would like to get the camera viewing angle of a pointcloud which is displayed using SceneWidget() whose scene is set like this:

self.window = gui.Application.instance.create_window("Open3D", width, height)
self._scene = gui.SceneWidget()
self._scene.scene = rendering.Open3DScene(self.window.renderer)

If I use o3d.visualization.Visualizer(), I can get it using get_view_control(), but cannot figure out how to get it using SceneWidget.

I tried to get the renderer object from Visualizer() thinking it could be passed to rendering.Open3DScene() but Visualizer() only has a get_render_option()

UPDATE: Thanks @saurabheights for the answer. What I am trying to do is to load a pointcloud, rotate it, get/save it's view matrix and then for all other pointclouds, use this view matrix. So that I dont have to rotate the pointcloud each time. My intuition is that I could combine get_view_matrix() and open3d.visualization.rendering.Camera.look_at(). But I am trouble trying it. How can I do it?

Solution

  • The properties of camera of SceneWidget are available via widget3d.scene.camera. Notice the class relationship:- SceneWidget -> Open3dScene -> Camera.

    You should be able to get view matrix from

    widget3d.scene.camera.get_view_matrix()

    Note - You should rename _scene to widget, makes it easier to infer the class of the object.