Thank you for your interest in Aspose.Slides.
I have observed your comments and like to share with you that it is not an issue, but the explanation for this behavior is the different interpretations of 3D rotation properties in ECMA-376 standard and PowerPoint. The chart.xml ‘rotX’ item is interpreted as ‘Y rotation’ and ‘rotY’ - as ‘X rotation’ option in PowerPoint UI (see explanation.jpg).
Moreover, the description of these properties is as under,
Chart.Rotation3D.RotationX property returns or sets the rotation degree around the X-axis, i.e. in the Y direction for 3D charts (between -90 and 90 degrees). The property matches with the 18.104.22.168 rotX (X Rotation) item in ECMA-376 and with the “Y Rotation” option in PowerPoint 2007+
Chart.Rotation3D.RotationY property returns or sets the rotation degree around the Y-axis, i.e. in the X direction for 3D charts (between 0 and 360 degrees). The property matches with the 22.214.171.124 rotY (Y Rotation) item in ECMA-376 and with the “X Rotation” option in PowerPoint 2007+.
I hope this will clarify the concept. Please share if I may help you further in this regard.