This method should add a new point to the frame hierarchy and Make sure a new node is not added if overlap.

public void ToAddBonePoint( double testDiameter, double centerX, double centerY)
    {
        if (selectedNode == null){
            selectedNode = new BoneNode( testDiameter, centerX, centerY);

        }

I have

new BoneNode( testDiameter, centerX, centerY); underline red, message is
the constructor BoneNode (double double double ) is undefined

thanks in advance

Is it because you haven't declared a constructor with 3 doubles as arguments? Or somehow your class can't "see" the constructor because you haven't import the BoneNode class?