SYNOPSIS

tw

DESCRIPTION

The tw tweak command is useful for interactively setting the view point of a 3D plot. The graphics filter should be a display terminal. If the filter is associated with a printer, you will generate a plot each time you hit <return>.

Although you normally specify the orientation of the 3D axis in C-PLOT using view-point coordinates, the tw command works in terms of rotation angles. When you enter tw,the current rotation angles, the view-point radial distance and the view-point coordinates are printed, along with the four current tweak deltas. The first three deltas are the increments to the rotation angles that will be made each time you hit <return>. The last delta is the increment to the view-point distance.

If you just hit <return>, the current deltas will be added to the angles and view-point distance, the view point will be recalculated and the 3D plot will be redrawn. However, you can enter new deltas before you hit <return>. Only the values you enter - up to four - will be used. You can use a dot in any of the positions to use the current value for that delta. A single minus sign in one of the positions changes the sign of the corresponding delta. Entering =numb sets the value of the corresponding delta to numb.

Type ^D to quit tweak mode and restore text mode on graphics terminals.

On video terminals, such as 4014 emulators, that use a serial line for sending both text and graphics, use the zq command to turn off echoing of input and the sending of output text to the terminal before entering tw.When you exit tweak mode, echoing of input and sending of output will be restored.

The tw command also functions in 2D mode, although only the first delta, which corresponds to the swivel parameter (see sw ) has any effect.