There is a function requirement that  display the key 3D points and draw a spline(NURBS,polyline etc.) through these 3D points.
Qt Data Visualization module is a best module but it lose this function logtime.

Now, i use Q3DScatter and QScatter3DSeries  to display all key 3D points .
For display a spline through these 3D key points , i make a lot of 3d points from a spline, to display a lot points to display spline curve.  but the effect is not good。
Clound your team to add the display 3Dcurve function?