Group Objects

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Group objects enable you to treat a number of axes child objects as one group. For example, you can make the entire group visible or invisible, select all objects when only one is clicked, or apply a transform matrix to reposition the objects by setting only one property on the group object.

There are two group objects:

hggroup Use when you want to create a group of objects and control the visibility or selectability of the group based on what happens to any individual object in the group.
hgtransform Use when you want to transform a group of objects. Transforms include rotation, translation, scaling, etc.

The difference between the hggroup and hgtransform objects is the ability of the hgtransform object to apply a transform matrix (via its Matrix property) to all objects for which it is the parent.


Create hggroup object

Example: group1

An hggroup object can be the parent of any axes children except light objects, as well as other hggroup objects. You can use hggroup objects to form a group of objects that can be treated as a single object.


The function makehgtransform creates 4-by-4 transform matrix



M = makehgtform
M = makehgtform('translate',[tx ty tz])
M = makehgtform('scale',s)
M = makehgtform('scale',[sx,sy,sz])
M = makehgtform('xrotate',t)
M = makehgtform('yrotate',t)
M = makehgtform('zrotate',t)
M = makehgtform('axisrotate',[ax,ay,az],t)


Use makehgtform to create transform matrices for translation, scaling, and rotation of graphics objects. Apply the transform to graphics objects by assigning the transform to the Matrix property of a parent hgtransform object. See Examples for more information.

M = makehgtform returns an identity transform.

M = makehgtform('translate',[tx ty tz]) or M = makehgtform('translate',tx,ty,tz) returns a transform that translates along the x-axis by tx, along the y-axis by ty, and along the z-axis by tz.

M = makehgtform('scale',s) returns a transform that scales uniformly along the x-, y-, and z-axes.

M = makehgtform('scale',[sx,sy,sz]) returns a transform that scales along the x-axis by sx, along the y-axis by sy, and along the z-axis by sz.

M = makehgtform('xrotate',t) returns a transform that rotates around the x-axis by t radians.

M = makehgtform('yrotate',t) returns a transform that rotates around the y-axis by t radians.

M = makehgtform('zrotate',t) returns a transform that rotates around the z-axis by t radians.

M = makehgtform('axisrotate',[ax,ay,az],t) Rotate around axis [ax ay az] by t radians.

Note that you can specify multiple operations in one call to makehgtform and the MATLAB software returns a transform matrix that is the result of concatenating all specified operations. For example,

m = makehgtform('xrotate',pi/2,'yrotate',pi/2);

is the same as

m = makehgtform('xrotate',pi/2)*makehgtform('yrotate',pi/2);


Tomas Moller and Eric Haines, Real-Time Rendering, A K Peters, Ltd., 1999.

Maintained by John Loomis, last updated 13 Jan 2010