## Name

knob — Provides a method for simulating knob input. With no options, it will display the current values for the knobs.

## Synopsis

`knob` [-e -i -m -v] [[-o] | [v] | [m] | [e] | [k]] [[zap] | [zero] | [`id` [`val`]]]

## DESCRIPTION

The knob command is used internally by MGED in the processing of knob input devices and is not recommended for users. The knob command provides a method for simulating knob input. With no options, it will display the current values for the knobs. With the zap or zero command provided, all the knob values will be reset to zero. If an id and valueare provided, the specified knob setting will be simulated. If the -i option is specified, then the value provided will be used as an increment to be applied to the indicated knob. The knobs have different functions depending on the current mode. For example, if in primitive or matrix edit mode and a rotation or translation function is selected, the knob effects are applied to the edited object by default. However, the -v (view coordinates) and -m (model coordinates) options may be used to adjust the view without modifying primitives or matrices. The -e option allows the knob effects to be applied to the edited object when they would normally be applied to the view. The -o option allows the origin of rotation to be specified with v, m, e, and k, indicating view, model, eye, and keypoint, respectively. The units for value are degrees for rotation and local units for translation. The available knob ids are:

- x -- rate-based rotation about horizontal axis.

- y -- rate-based rotation about vertical axis.

- z -- rate-based rotation about axis normal to screen.

- X -- rate-based translation in horizontal direction.

- Y -- rate-based translation in vertical direction.

- Z -- rate-based translation in direction normal to screen.

- S -- rate-based Scale or Zoom.

- ax -- absolute rotation about horizontal axis.

- ay -- absolute rotation about vertical axis.

- az -- absolute rotation about axis normal to screen.

- aX -- absolute translation in horizontal direction.

- aY -- absolute translation in vertical direction.

- aZ -- absolute translation in direction normal to screen.

- aS -- absolute Scale or Zoom.

- xadc -- absolute translation of adc in horizontal direction (screen coordinates -2048 to +2048).

- yadc -- absolute translation of adc in vertical direction (screen coordinates -2048 to +2048).

- ang1 -- absolute rotation of adc angle1 (degrees).

- ang2 -- absolute rotation of adc angle2 (degrees).

- distadc -- distance setting of the adc (screen coordinates -2048 to +2048).

## EXAMPLES

The example shows the use of the knob command with the y option to rotate a view about the vertical axis.

Example 1. Rotate a view about the vertical axis.

`mged>` `knob y 1`

  Starts the view rotating about the vertical axis.

## BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to <devs@brlcad.org>, or via the "cadbug.sh" script.