1.7 Using the dynamic rotations

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The OpenGL driver within FEMGV 6 offers real-time interaction for rotations, scales and shifts. If a dial box is available:

Dial	Function
0	Rotate about the X axis
1	Shift along the X axis
2	Rotate about the Y axis
3	Shift along the Y axis
4	Rotate about the Z axis
5	Z axis scale

If a dial box is not available then a combination of the CTRL key and the mouse may be used:

Key	Mode
CTRL-Left Button	Rotation
CTRL-Middle Button	Scaling
CTRL-SHIFT-Left Button	Scaling (two-button mouse)
CTRL-Right Button	Translation

With the mouse pointer inside the graphics drawing area, hold down the CTRL key and then press and hold a mouse button to enter the desired 'interaction' mode. As long as the CTRL key is held down you may swap modes by releasing and pressing any of the mouse buttons. To exit from this 'interaction' mode, simply release the CTRL key and the mouse button.



Rotation

To understand how rotations are achieved you should imagine that you are manipulating a sphere which fits around the model. Your finger is on the surface of the sphere at the position indicated by the mouse cursor. Moving your finger will rotate the sphere and hence the model. To reposition your finger on the sphere, release the lefthand mouse button, reposition the mouse cursor and then press the lefthand button again.



Translations

Simply moving the mouse will result in a corresponding X or Y axis shift.



Scaling

Moving the mouse to the left will zoom out and moving it to the right will zoom in.



Note that dynamic rotations are available during picking operations.



Two Button Mouse : when using a two button mouse a combination of CTRL-SHIFT-Left Button gives the equivalent of middle mouse button (as shown in the above table and this is the case consistently throughout FEMGV6).

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