I have a work around now. I can get the behavior I'm looking for if I do the following:

* Translate the item to the rotation center point
* Rotate the item
* Translate the item back to the starting position

See the code below for details. I still don't understand why setTransformOriginPoint() doesn't work. Can any Qt experts out there shed some light on this.

Brian

Qt Code: 
  1. void MainWindow::updateRotate(qreal value)
  2. {
  3.     QTransform txf = QTransform();
  4.  
  5.     rotateAngle = 360*value;
  6.  
  7.     switch (rotateAxis)
  8.     {
  9.     case 0:
  10.         // Up arrow - Rotate along top axis
  11.         txf.translate(item->boundingRect().width()/2, 0);
  12.         txf.rotate(rotateAngle, Qt::XAxis);
  13.         txf.translate(-item->boundingRect().width()/2, 0);
  14.         //item->setTransformOriginPoint(item->boundingRect().width()/2, item->boundingRect().height()/2);
  15.         break;
  16.  
  17.     case 1:
  18.         // Right arrow - Rotate along rigth axis
  19.         txf.translate(item->boundingRect().width(), item->boundingRect().height()/2);
  20.         txf.rotate(rotateAngle, Qt::YAxis);
  21.         txf.translate(-item->boundingRect().width(), -item->boundingRect().height()/2);
  22.         //item->setTransformOriginPoint(item->boundingRect().width(), item->boundingRect().height()/2);
  23.         break;
  24.  
  25.     case 2:
  26.         // Left arrow - Rotate along left axis
  27.         txf.translate(0, item->boundingRect().height()/2);
  28.         txf.rotate(rotateAngle, Qt::YAxis);
  29.         txf.translate(0, -item->boundingRect().height()/2);
  30.         //item->setTransformOriginPoint(0, item->boundingRect().height()/2);
  31.         break;
  32.  
  33.     case 3:
  34.         // Down arrow - Rotate along bottom axis
  35.         txf.translate(item->boundingRect().width()/2,item->boundingRect().height());
  36.         txf.rotate(rotateAngle, Qt::XAxis);
  37.         txf.translate(-item->boundingRect().width()/2,-item->boundingRect().height());
  38.         //item->setTransformOriginPoint(item->boundingRect().width()/2,item->boundingRect().height());
  39.         break;
  40.     }
  41.  
  42.     item->setTransform(txf, false);
  43. }
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