OpenCOLLADA kinematics issues

Other Standards COLLADA
1

Dear all,

I am new to OpenCOLLADA and have several questions about kinematics.
I want to parse <articulated_systems> but it is unclear for me how it implemented in OpenCOLLADA. Is there any class related to articulated systems, or how can I access it?

Best regards,
Anton

2

Hi Anton.

I am not exactly sure, I think you need to check class KinematicsController from COLLADAFW. Let me know about your results.

best regards,
Alexey

3

Thank you, Alexey!

Don’t you know what is the difference between Kinematics Scene in COLLADAFW and in COLLADASaxFWL?

Regards,
Anton

4

COLLADASaxFWL has “low-level” classes responsible for collada xml parsing and so on.
At some point COLLADASaxFWL puts all xml data to data structures of COLLADAFW.
You should use COLLADAFW. Here is a small example, how you can get articulated_system information.

virtual bool writeKinematicsScene( const COLLADAFW::KinematicsScene* kinematicsScene )
{
const COLLADAFW::KinematicsControllerArray& controllers = kinematicsScene->getKinematicsControllers();
std::cout << “found " << controllers.getCount() << " controllers” << std::endl;
for (size_t i = 0; i < controllers.getCount(); i++) {
COLLADAFW::KinematicsController* controllerPtr = controllers[i];
const COLLADAFW::AxisInfoArray& axisInfos = controllerPtr->getAxisInfos();
std::cout << “found " << axisInfos.getCount() << " axis_info tags” << std::endl;
for (size_t x = 0; x < axisInfos.getCount(); x++) {
const COLLADAFW::AxisInfo& axisInfo = axisInfos;
std::cout << "found axis with index: " << axisInfo.getIndex() << std::endl;

            std::string isActive = axisInfo.getIsActive()==true ? "true":"false";
            std::cout &lt;&lt; "   axis active: " &lt;&lt; isActive &lt;&lt; std::endl;
            std::string isLocked = axisInfo.getIsLocked()==true ? "true":"false";
            std::cout &lt;&lt; "   axis locked: " &lt;&lt; isLocked &lt;&lt; std::endl;

            COLLADAFW::JointPrimitive* jointPrimitivePtr = axisInfo.getJointPrimitive();
            COLLADABU::Math::Vector3 axis = jointPrimitivePtr-&gt;getAxis();
            std::cout &lt;&lt; "   joint axis: " &lt;&lt; axis.x &lt;&lt;" "&lt;&lt; axis.y &lt;&lt;" "&lt;&lt; axis.z &lt;&lt; std::endl;

            float softLimitMax = jointPrimitivePtr-&gt;getSoftLimitMax();
            float softLimitMin = jointPrimitivePtr-&gt;getSoftLimitMin();
            std::cout &lt;&lt; "   soft limit min: " &lt;&lt;softLimitMin &lt;&lt; " soft limit max: " &lt;&lt; softLimitMax &lt;&lt; std::endl;

            float hardLimitMax = jointPrimitivePtr-&gt;getHardLimitMax();
            float hardLimitMin = jointPrimitivePtr-&gt;getHardLimitMin();
            std::cout &lt;&lt; "   hard limit min: " &lt;&lt;hardLimitMin &lt;&lt; " hard limit max: " &lt;&lt; hardLimitMax &lt;&lt; std::endl;

            const COLLADAFW::MotionProfile& motionProfile = jointPrimitivePtr-&gt;getMotionProfile();
            float acceleration = motionProfile.getReferenceAcceleration();
            float deceleration = motionProfile.getReferenceDeceleration();
            float jerk = motionProfile.getReferenceJerk();
            float speed = motionProfile.getReferenceSpeed();
            std::cout &lt;&lt; "   acceleration: " &lt;&lt; acceleration &lt;&lt; " deceleration: " &lt;&lt; deceleration &lt;&lt; " jerk: " &lt;&lt; jerk &lt;&lt; "speed: " &lt;&lt; speed &lt;&lt; std::endl;
        }
    }
	return true;
}
5

Forgot to mention that you should read this thread about problem with KinematicsController copy construction, Here is the link Google Code Archive - Long-term storage for Google Code Project Hosting.

I also attached the model with the articulated_system. When you are working with kinematics models using openCOLLADA lib you should first do a model validation (use openCOLLADAValidator) to check if the model is valid against COLLADA 1.5 scheme.

6

Thank you for help, Alexey! But it is still unclear for me how tags <frame_origin>,<frame_tcp> and <frame_tip> are realized in OpenCOLLADA. How can i parse them?

Anton