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ANIM_OFFSET(nged)	     BRL-CAD User Commands	     ANIM_OFFSET(nged)

       anim_offset - create an animation table for an object rigidly attached
       to another object.

       anim_offset -o #	# # [-r] in.table out.table

       This filter operates on animation tables	of the type used by tabsub and
       anim_script.  Given a table specifying the position and orientation of
       one object at every applicable time, anim_offset	calculates the
       position	of another object which	is rigidly attached to it.

       The columns of the input	table should be	time, three columns of
       position, followed by yaw, pitch, and roll. The output will normally be
       a four-column file specifying time and position.	If the -r option is
       used, the output	is a seven-column file in which	the last three columns
       are copies of the orientation information from the input	file.

       The position of the object relative to the rigid	body should be given
       on the command line in the order	x, y, z, with the -o # # # option.
       These offset values should be as	measured from the centroid of the
       rigid body.

       This filter could be used, for example, to do an	animation where	the
       camera is placed	inside a moving	vehicle.

       Suppose that truck.table	contains the desired position of the center of
       the front axle of the truck as well as its orientation at each time.
       One row of the table might look like this:

	   35.2	12450	  -140 600  90.0      0.0  0.0

       Thus 35.2 seconds into the animation, the center	of the front axle will
       be at (12450, -140, 600), and the truck will be pointed in the positive
       y direction. (yaw = 90).

       Now, suppose we want the	camera to ride along in	the cab, above and
       behind the front	axle and somewhat to the left. To specify this offset,
       we use the coordinate frame of the truck, with the origin at the	center
       of the front axle, the x-axis to	the front, y to	the left, and z
       pointing	up. Let	the exact offset from the axle to the desired camera
       position	in this	case be	(-600, 900, 1200), in units of mm. Now we use
       the routine:

	   anim_offset -o -600 900 1200	< truck.table >	camera.table

       The result is a four-column table giving	the desired position of	the
       virtual camera at each time. The	row corresponding to the sample	row
       above would be:

	   35.2	11550	  -740 1800

       With the	-r option, the output would have been:

	   35.2	11550	  -740 1800 90.0      0.0  0.0

       Now tabsub and/or anim_script can be used to process these two
       animation tables	into an	animation script.

       The program will	only use orientations specified	as yaw,	pitch, and
       roll. You can get around	this using anim_orient,	which converts between
       different orientation representations.

       Carl J. Nuzman

       This software is	Copyright (c) 1993-2019	by the United States
       Government as represented by U.S. Army Research Laboratory.

       Reports of bugs or problems should be submitted via electronic mail to

BRL-CAD				  11/05/2021		     ANIM_OFFSET(nged)


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