Setting camera position/orientation with SofaPython

[Joshua]

Hi,

I’m having a bit of trouble figuring out how to modify the camera position/orientation. In the scene below, changing the parameters of the InteractiveCamera doesn’t do anything, and the object doesn’t show up at all in the OglViewport. I assume I’m screwing up something basic and would appreciate any help!

from stlib.scene import MainHeader, ContactHeader, Scene
from stlib.physics.rigid import Cube
import Sofa

def createScene(rootNode):
    scene = Scene(rootNode, plugins=["SofaSparseSolver"])

    Cube(rootNode, uniformScale=0.001)

    rootNode.createObject("InteractiveCamera", name="baseCamera", position="-0.00257779 -0.00358703 0.000986644",
                          orientation="0.588126 -0.212397 -0.213083 0.750727",  lookAt=[2.5, 5, 0],  distance=100000,
                          minBBox=[-5, 0, -8.66],  maxBBox=[10, 10, 8.66],  widthViewport=190, heightViewport=552)

    rootNode.createObject("OglViewport", name="view",
                          screenPosition="0 0", screenSize="250 250",
                          cameraPosition="-0.00257779 -0.00358703 0.000986644", cameraOrientation="0.588126 -0.212397 -0.213083 0.750727")

Thank you very much,
Josh

[beichun]

I would also like to know any suggestions on this (I’m using SofaPython3)!

[Hugo]

Hey @joshuaf and @beichun

First in the InteractiveCamera, you can not define both the lookAt and the orientation.
However, I am not sure why changing the values in the InteractiveCamera do not update its actual position.

@froy would you have a idea on this?

Best,

Hugo

[beichun]

I found that I have to use the opengl viewer (Sofa.Gui.GUIManager.Init(“MyScene”, “qt)) in order to make the interactiveCamera work.

However, I still cannot set the right camera orientation. I received the following warning:

[WARNING] [InteractiveCamera(camera)] Could not read value for data field orientation: array([0.70710678, 0. , 0. , 0.70710678])

The code I used to set the camera is:

        from scipy.spatial.transform import Rotation as R
        cam_lookAt = [0, 0, 0]
        cam_orientation = R.from_euler("x", np.pi/2).as_quat()
        self.root.addObject("InteractiveCamera",
                            name="camera",
                            orientation=cam_orientation,
                            lookAt=cam_lookAt,
                            distance=100,
                            fieldOfView=66,
                            zNear=-10,
                            zFar=55.69)

Any advice?

[jnbrunet]

Hey @beichun

Indeed, you have to use the Qt viewer since the QGLViewer has its own internal camera.

For your error with the orientation, the data has to be converted to a python list. In your code, simply change cam_orientation = R.from_euler("x", np.pi/2).as_quat() to cam_orientation = R.from_euler("x", np.pi/2).as_quat().tolist().

J-N

[beichun]

It works nicely. Thank you!

I want to ask another question, how do I set the up direction of camera? Although my orientation is correct, the rendered view is upside down.

[Hugo]

Hey @beichun

Maybe a screenshot would help. Or just try to adjust your parameters.
Best,

Hugo

[Scheikl]

Hi!
I have a related problem.
I am able to control the internal data of an interactiveCamera, but it does nothing to the view itself, even though I made sure I am using the OpenGL view.

You can find a video of the behavior here: https://cloud.ipr.kit.edu/s/y2tjFW2Za4CX5p2

The code to set the pose is

def move_cam(camera, pose: Tuple[float, float, float, float]):
    camera.position.value = pose[:3]
    camera.orientation.value = pose[3:]

SOFA: v2012_beta
SP3: master

Cheers,
Paul

[Scheikl]

Hi past @scheikl ,
you have to create the interactiveCamera at the root node to get the correct behavior.

Maybe @hugo can elaborate as to why that is. 😀

Cheers,
Paul

[Author]

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