如何仅在Z轴上旋转3D对象？

我们使用3DTools（http://3dtools.codeplex.com）绘制一条3d线，它允许用户通过鼠标旋转它。我有问题，如何限制用户只能在Z轴上旋转它？或仅在X轴上，仅在Y轴上？如何仅在Z轴上旋转3D对象？


<tool:TrackballDecorator > 
    <tool:Interactive3DDecorator 
     ContainsInk="True"> 
     <Viewport3D> 
      <Viewport3D.Camera> 
       <PerspectiveCamera x:Name="camera1" Position="4.89,-11,5" LookDirection="-4.89,11,-5" 
            FieldOfView="45" UpDirection="-4,9,-1"/> 
      </Viewport3D.Camera> 
      <ModelVisual3D x:Name="modelVisual3D"> 
       <ModelVisual3D.Children> 
        <tool:ScreenSpaceLines3D x:Name="axisX" Color="Cyan" 
         Thickness="2.0" 
         Points="0, 0, 0, 5, 0, 0" /> 
        <tool:ScreenSpaceLines3D Color="LightCyan" 
         Thickness="2.0" 
         Points="-5, 0, 0, 0, 0, 0" /> 
        <tool:ScreenSpaceLines3D x:Name="axisY" Color="Green" 
         Thickness="2.0" 
         Points="0,0,0, 0,5,0"/> 
        <tool:ScreenSpaceLines3D Color="LightGreen" 
         Thickness="2.0" 
         Points="0,-5,0, 0,0,0"/> 

        <tool:ScreenSpaceLines3D x:Name="axisZ" Color="Red" 
         Thickness="2.0" 
         Points="0,0,0, 0,0,5"/> 
        <tool:ScreenSpaceLines3D Color="LightPink" 
         Thickness="2.0" 
         Points="0,0,-5, 0,0,0"/> 
       </ModelVisual3D.Children> 
      </ModelVisual3D> 
     </Viewport3D> 
    </tool:Interactive3DDecorator> 
</tool:TrackballDecorator>

来源

2009-11-16 Cooper.Wu

你确定它旋转线？我认为它只是使用TrackballDecorator旋转相机... – 2009-11-16 07:47:30

@SMART_n，您是对的，感谢您的提示，在阅读3DTools源代码后我知道它，并且我找到了一种限制Z轴旋转的方法，它可以工作，但不好。 – 2009-11-16 14:55:42

什么意思是“不好”？ – 2009-11-16 15:29:17

与这一个替换 'Trackball.cs' Trackball.Track（）方法：

private void Track(Point currentPosition) 
    { 
     Vector3D currentPosition3D = ProjectToTrackball(
      EventSource.ActualWidth, EventSource.ActualHeight, currentPosition); 

     Vector3D axisToRotate = new Vector3D(0, 1, 0); // Rotation around Y only 

     Vector3D currProjected = Vector3D.CrossProduct(axisToRotate, currentPosition3D); 
     Vector3D prevProjected = Vector3D.CrossProduct(axisToRotate, _previousPosition3D); 
     double angle = Vector3D.AngleBetween(currProjected, prevProjected);    

     int sign = Math.Sign(Vector3D.DotProduct(
      axisToRotate, 
      Vector3D.CrossProduct(_previousPosition3D, currentPosition3D))); 

     if (sign != 0) 
     { 
      Quaternion delta = new Quaternion(axisToRotate * sign, -angle); 

      AxisAngleRotation3D r = _rotation; 
      Quaternion q = new Quaternion(_rotation.Axis, _rotation.Angle); 

      q *= delta; 

      _rotation.Axis = q.Axis; 
      _rotation.Angle = q.Angle; 
     } 

     _previousPosition3D = currentPosition3D; 
    }

来源

2009-11-18 08:45:16

太棒了，工作得很好。 – 2009-11-18 10:10:23

如何仅在Z轴上旋转3D对象？

回答

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