How to add a camera on my robot tip?

[TeoREN0217]

Hi!
I'm trying to add a camera on my robot tip and I don't know how to do that.
I have found BaseCamera InteractCamera and Camera but didn't understand the params and how to use that? Are there any tutorials or examples?

[monkeygame]

The params are in the constructor of the corresponding class.
you can try to modify it to get familiar quickly
I've seen examples that might help you:
examples\Demos\caduceus.scn
examples\Components\visualmodel\OglViewport.scn
examples\Components\visualmodel\RecordedCamera
examples\Components\topology\TopologicalModifiers\RemovingTetra2TriangleProcess_performanceTest.scn

[TeoREN0217]

Hi~
Thanks for your reply.
I have a little confused about these camera. For I want to add a traditional rgb camera to get some visual messages, I found that these cameras are more like setting a view angle in the sofa GUI. I'm not sure am I right or is there any camera have the function like I want?

[hugtalbot]

Does this forum discussion help @TeoREN0217 : https://www.sofa-framework.org/community/forum/topic/set-up-camera-following-a-tool-in-the-scene/ ?

[TeoREN0217]

Hi @hugtalbot !
Thanks for your reply! I tried RecordedCamera before, but it's orientation has a little problem: it's always look forward a straight direction. For my robot is a tube and it actually hasn't an object has an orientation property. I use the CableActuator cable position which at the end of the tip. By using three positions we will have a 3D-flat and calculate the normal vector of the flat, and do some changes between orientation, matrix. At the end, using Animation method to make it come true. Here is my method shared here which may help others:

def myAnimation(target,camera_position1,cable4,cable5,cable6,factor):  # here you define your anima # factor = (currentTime-startTime) / duration
            x1=cable4.dof3.position.value[34][0]
            y1=cable4.dof3.position.value[34][1]
            z1=cable4.dof3.position.value[34][2]
            x2=cable5.dof3.position.value[34][0]
            y2=cable5.dof3.position.value[34][1]
            z2=cable5.dof3.position.value[34][2]
            x3=cable6.dof3.position.value[34][0]
            y3=cable6.dof3.position.value[34][1]
            z3=cable6.dof3.position.value[34][2]
            p1=np.array([x1,y1,z1])
            p2=np.array([x2,y2,z2])
            p3=np.array([x3,y3,z3])
            A=p1-p3
            B=p3-p2
            A_B=np.cross(A,B)
            ret1=R.from_rotvec(A_B)
            q1=ret1.as_quat()
            q2=[ 0, 0.7071068, 0, 0.7071068 ]
            ret2=R.from_quat(q1)
            matrix=ret2.as_matrix()
            rot=np.mat([[-1,0,0],[0,1,0],[0,0,-1]])
            # q3=q1.rotateFromQuat(q2)
            matrix_rot=rot*matrix
            # print(matrix_rot)
            ret3=R.from_matrix(matrix_rot)
            q_final=ret3.as_quat()
            myValue=[target.position.value[0][0],target.position.value[0][1],target.position.value[0][2],q_final[0],q_final[1],q_final[2],q_final[3]]
            # print(myValue)
            # print(camera_position.cameraRigid.value)
            camera_position1.cameraRigid.value=myValue
            # camera_position2.orientation.value=q_final
            # camera_position2.position.value =target.position.value[0]
        # rootNode.addObject('RecordedCamera',position=[0,0,131],orientation=[0,1,0,0],distance=0.1,fieldOfView=60)
        rootNode.addObject("OglViewport", name="OglViewport",screenPosition="300 0",screenSize="400 400",cameraRigid='0 0 131 0 1 0 0',zFar=141,zNear=1.3)
        
        # animate(myAnimation, {'target': effectors.MechanicalObject,'camera_position1':rootNode.OglViewport,'camera_position2':rootNode.RecordedCamera,'cable4':self.node.cable4,'cable5':self.node.cable5,'cable6':self.node.cable6},duration=5)
        animate(myAnimation, {'target': effectors.MechanicalObject,'camera_position1':rootNode.OglViewport,'cable4':self.node.cable4,'cable5':self.node.cable5,'cable6':self.node.cable6},duration=5)

But actually there are still some problems:
When I use RecordedCamera, this method will work. But if I add some obstacles in the scene, some times it look forward a straight direction(like the picture). But when I use the OglViewport , it worked well with the same method and same orientation. It confused me a lot. Is the problem of my animate method which may has a delay?