ALT + O

Support Basics & Interface
1

What alt+o(clear origin) is it for?

2

It helps in parenting relations.

Stefano

3

Stefano, please say something more, I know it takes time to explain but I hate to do things without understanding what I’m doing. And it happens all the time not to finish a modeling procedure because of some missing tips.

Stamatis

4

When you do a path animation and you parent the child to the Path the center of the cild is usually off the path. By using ALT-O you ‘clear the origin’ and the center of your Child goes to the Path!

Stefano

P.S. Sorry for being that laconic on first answer, more on this in the DOC!
http://download.blender.org/documentation/html/x7757.html

5

FTFM (from the fabulous manual)

ALT-O
Clear Origin. The ‘Origin’ is erased for all Child Objects, which causes the Child Objects to move to the exact location of the Parent Objects.

CTRL-P
Make Parent. The active Object becomes the Parent of the selected Objects. All transformations of the Parent are now passed on to the Children. This allows you to create complex hierarchies. As part of the ‘Make Parent’ operation, an inverse of the Parent transformation is calculated and stored in the Child Object. This inverse may make it seem as if all transformations remained unchanged after Make Parent was executed. Depending on the type of Object, special Parent relationships can be selected.

ALT-P
Clear Parent. All selected Child Objects are unlinked from the Parents. A PopupMenu asks you to make a selection:

“Clear Parent”: the selected Child Objects are unlinked from the Parent. since the transformation of the Parent disappears, this can appear as if the former Children themselves are transformed.

“… and keep transform”: the Child Objects are unlinked from the Parent, and an attempt is made to assign the current transformation, which was determined in part by the Parent, to the (former Child) Objects.

“Clear Parent inverse”: The inverse matrix of the Parent of the selected Objects is erased. The Child Objects remain linked to the Objects. This gives the user complete control over the hierarchy.

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6

You guys are great!!!
Thank you very much.

Stamatis

p.s Stefano you have help me alot of times without even know it.
But I don’t always have the oportunity and/or the time to say thank you.

7

It might be useful to add that, when using alt+Okey, there are two cases :
in the case of an animation path, it is the child’s center that will move to the beginning of the path
while in any other parenting case the child’s center will move to overlap the center of the parent.

8

It will only move to the start of the path if you are on the frame corresponding to the start of the path. Otherwise, it will move to the point corresponding to the current frame.

In clear, it clears the location offset of the child.

Martin

9

Thank you all of you. Now its clear for ever.

Stamatis

10

Is there a way to precisely center (or re-center) the child on the CENTER of an animation path? I use circular paths for rotating planets while controlling their orientation by controlling the orientation of the path and their rotation speed with the path speed IPO curve. The only way I’ve found to avoid wobbling is to make the path very very tiny, which then means I have to put it the path in a new layer so I can select it (and I’m close to running out of layers) when I need to adjust it or need to temporarily unparent it. Some advanced advice on how to use right-click to select the object I want on the first try would help (OOPS window doesn’t seem to allow me to really select objects in the usual sense, for example if you select an object in OOPS and then hit materials button F5 you get materials for the object that was previously selected). Thanks.

11

I think you would get better results with keyframing and an armature, the root of which should be at the gravitational center. Rotate the planet 360 degree cycle using 4 keyframes, set the animation mode to linear, and cyclic, Then do the same thing to the armature over a longer cycle. Should work like clockwork, and if something wobbles, just delete the ipos along the offending axis.

12

First select the path and send the 3D cursor at it’s center using shift+Skey and selecting curs -> sel. Then select the child alone and use shift+Skey followed by selecting sel -> curs in the dialog that pops up.

I use circular paths for rotating planets while controlling their orientation by controlling the orientation of the path and their rotation speed with the path speed IPO curve. The only way I’ve found to avoid wobbling is to make the path very very tiny, which then means I have to put it the path in a new layer so I can select it (and I’m close to running out of layers) when I need to adjust it or need to temporarily unparent it. Some advanced advice on how to use right-click to select the object I want on the first try would help (OOPS window doesn’t seem to allow me to really select objects in the usual sense, for example if you select an object in OOPS and then hit materials button F5 you get materials for the object that was previously selected). Thanks.

There is such a thing as a data select window in Blender and it is perfect to select tiny objects or objects lost in a mess of others. The shortcut to open it is shift+F4. The selection occurs when LMBing (or RMBing for that matter, which seems to work just the same) on the name of the object with the mouse. The last object selected will be the active one, as usual, and the Akey can be used to select all, as usual again.

Jean

13

Thanks! The DataView Window makes my life 1000% easier. Don’t know why I didn’t see it in the Manual :expressionless: .
This forum has the most helpful responses of any on the web, bar none.