local space vs. object space

[akewt]

Extract from Maya help.

world space: The coordinate system for the entire scene. Its origin is at the center of the scene. The grid you see in view windows shows the world space axes.

local space: The coordinate system (origin and axes) from the point of view of an object's parent node in the hierarchy of objects.

I believe world coords to be irrespective of an object and local space to be associated with an object.

If you parent/group and object, its coordinates will change according to its offset from the parent/group node. That group node will have world coordinates along with the obect/s within that node. So if I had a group that was 30 units away from the world axis in Y and an object within its hierachy also with a transform of 1 unit in Y. The object within the hierachy would have a local coordinate of 0,1,0 and a world coordinate of 0,31,0.

Hope this makes it clear.

Kev

[learning3D]

ok, thank you very much - i understand the difference...!

BUT...

why i have in the movetoolsettings the option for local?

[akewt]

well if your object has been rotated for instance, you can move it along its axis respective of the rotation. in other words on its local axis. if you were to move the object on world axis it would always align the axis to the world. in other words straight to the grid no matter how you rotated it.

[learning3D]

yes understand - thx ! :-D

but why i have only

- local mode with move & rotate
- object mode only with move
- and scale has NO object & local

???

[Emil3d]

I think the terminology in the options of the translate tools could be quite confusing for an inexperienced user.
First thing to understand is that the orientation options in the tools’ settings affect only the orientation of the manipulator for the different transform tools – the actual axis of the object in its transform node is not affected at all.

To check the actual axes and what can be done with them, look at the transform node of your object in the Attribute Editor. In addition to the Rotate, you will also see the Rotate Axis attribute. The Rotate Axis is simply an additional offset to the Rotate attribute’s values. So that for example instead of let’s say having 90 for the Rotate you can type 30 for the Rotate Axis and 60 for the Rotate (90 = 30 + 60). You can also change that interactively by selecting Local Rotational Axis under the question mark icon from the component celection masks section on the Status bar and then rotate the axis with the Rotate tool.

Now after understanding this, you need to know that Local in the Rotate tool options is equal to Along Rotational Axis in the Move tool options, which in both cases will align the manipulators with the values of the Rotate attribute.
The Local option for the Move Tool, aligns the manipulator with its parent and the confusing part is that it has nothing to do with the Local option for the Rotate Tool which I explained above.

I know its confusing so let’s try to sum it up-

The Move Tool has most orientation options where:
Along Rotational Axis – aligns the manipulator with the values of the Rotate attribute of the object.
Object - aligns it with values that are the total sum of the values for the Rotate and Rotate Axis attributes of the object.
Local – aligns it with the values that are the total sum of the values for the Rotate and Rotate Axis attributes of the object’s parent.

The Rotate Tool has only 2 orientation options, where Local, aligns its manipulator with the values of the Rotate attribute of the object

The Scale Tool has no orientation options and always scales along an orientation aligned with values that are the total sum of the values for the Rotate and Rotate Axis attributes of the object.

I hope may explanation makes sense. As to why one tool has less options than another, I think only Alias/Autodesk can answer this and this is where you can make feature requests.

In this thread (http://www.3dbuzz.com/vbforum/showthread.php?t=133762&highlight=local) I suggested one workaround that can change the orientation of the Scale tool.

[learning3D]

wow !!! emil3d thx! :-))

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