Gus Sentementes of The Baltimore Sun reports on a patent application filed by Apple last month, which explains a problem that 3D CAD users face:
There is a need for electronic devices with touch screen displays that provide more transparent and intuitive user interfaces for navigating in 3D virtual spaces and manipulating 3D objects in these virtual spaces.
The solution that Apple patented covers all devices, including multi-touch sensitive tablets, and involves the following manipulations by finger gestures:
- Simultaneously zooming and translating (moving) 3D objects.
- Zooming objects to a predetermined size of the screen, and then returning to the original size -- with animated transitions.
- Changing 3D perspective viewpoints.
- Panning in various directions.
- Rotating and twisting the viewpoint and objects (separately) about various axes.
The patent becomes tedious to read...
("in response to detecting the multi-finger swipe gesture:if the multi-finger swipe gesture initially moves within a predetermined range of angles with respect to the touch screen display, displaying an animated rotation of the first three-dimensional virtual object about an axis in the plane of the touch screen display that is perpendicular to the direction of movement of the multi-finger swipe gesture while maintaining display of the second perspective in the three-dimensional virtual space")
...but it appears to me that the axes can be absolute (WCS) or relative to objects (UCS, in AutoCAD parlance). Also, there seems to also be an indication of multiple, independent viewports.