How do I set the 3D coordinates of the virtual camera when rendering point clouds?

[Zhouwudexiazhou]

I want to simulate the situation of people watching the volume video with the head display, because the image rendered by the point cloud is different from the distance. However, in oped3d, there is only the look at function of the viewing point, but there is no function to set the camera's 3d space coordinates. I want to ask how can I set the camera's desired 3d coordinates to render the point cloud picture?

[cwreynolds]

Hi. Which visualizer are you using? There is a newer open3d::visualization::visualizer::O3DVisualizer and the older “legacy” open3d::visualization::Visualizer. (Also which language? Most people use python. I'm using c++ names here.)

In the first case you should be able to use O3DVisualizer::SetupCamera(fov, center, eye, up)

In the legacy case, I had exactly the same confusion: why can't I directly set the “eye” point of ViewControl?! I recently described my work-around here: #7023 (“look at” add-on to legacy Visualizer/ViewControl).

[cwreynolds]

I think the answer is yes, but I have not used Open3D from Python for a year or so. So I cannot quickly prototype a version of my work-around in Python.

I did find the Python API doc for look_at(). See also the legacy Visualizer method get_view_control(), the class ViewControl, and its methods convert_from_pinhole_camera_parameters() / convert_to_pinhole_camera_parameters().

Perhaps @ssheorey can suggest someone with better experience to help you translate my c++ code to Python?

[cwreynolds]

Maybe the answer is no. I tried to translate my code to Python. That required making a new environment for Open3D 0.18.0 since the last time I used Open3D from Python the current release was 0.17.0, which had a bug preventing modification of ViewControl.

But as near as I can tell, there is no direct Python analog to the c++ function open3d::visualization::gl_util::LookAt() which my code is based on. The symbol “gl_util” does not appear in the Open3D Python doc at all. It would be possible to write such a function, but I think that is probably going too far in the wrong direction.

You might be better off to look into the newer O3DVisualizer class which has a function providing look-at-up functionality: setup_camera()

[Zhouwudexiazhou]

I have tested O3DVisualizer class in python. It work!!! Thank you bro,Thank you!!!

[Zhouwudexiazhou]

也许答案是否定的。我尝试将我的代码翻译成 Python。这需要为 Open3D 0.18.0 创建一个新环境，因为上次我从 Python 使用 Open3D 时，当前版本是 0.17.0，它有一个错误阻止修改ViewControl。

但据我所知，没有与open3d::visualization::gl_util::LookAt()我的代码所基于的 C++ 函数直接对应的 Python 函数。符号“gl_util”根本没有出现在 Open3D Python 文档中。可以编写这样的函数，但我认为这可能走得太远了。

你最好研究一下较新的O3DVisualizer类，它有一个提供查找功能的函数：setup_camera()

hey,bro.I read the C++ version of O3DVisualizer class code.When i change the fov in setupcamera.Why the photo change together?It do not change!! the photo1 with the fov value in 10 degree and photo2 with fov value in 60 degree are the same!!
The C++ code is:

It does not use the fov!!

[cwreynolds]

Good catch @Zhouwudexiazhou! I added a comment on your issue #7033 pointing back to your comment just above.