Vertex coordinates bug

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phobos
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Joined: Tue Mar 09, 2004 5:38 pm

Vertex coordinates bug

Post by phobos »

I'm not sure if there's a solution to this, or if it's the way Blender was designed.
Why are vertex coordinates relative to the object's "center"(and not the world origin)?
Why is the center the same as the pivot (for translation)?.

Here's an example file showing what I mean:

http://webpages.charter.net/phobos/coord-bug.blend

Note the numeric entry dialog (n).

The first surface has its "center" at the center of the object and all vertices' positions are called up relative to that center.

But, if you position the object "center" at the scene origin, (0,0,0), the coordinates will be proper (their true position in XYZ space).

Why is this?

However... by positioning the "center" at the world origin, you effectively negate any way to precisely position the whole object (in object mode, not edit) by it's "pivot" (which is the same as the center apparently).

Shouldn't any given object have both a pivot point and origin point? (WCS -- world coordinate system).

Alternatively, is the numeric input dialog wrong? Can it only display positions relative to a center?

Image
Figure 1 -- Second object has center positioned at world origin).

This is strange, as it's the only way of precisely controlling the position of a given vertex other than snapping (but snapping cannot display its actual position, only relative movement).

Is this by design?

So far I've been able to understand that transforms in object mode alter the relative coordinates of geometry in edit mode (i.e. you scale it in object mode and the vertices show the same positions in edit), but this doesn't idea of the center and numeric entry doesn't seem to make much sense.

Also, is there a way to set the major grid subdivision to be something other than 10?

SirDude
Posts: 233
Joined: Sun Oct 13, 2002 7:37 pm
Location: University of Minnesota (USA)
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Post by SirDude »

It is by design. That way you do not need to move
an object to the origin to "play with it"

It would probably be a nice feature to also have the
world cords in the info window. For animations it makes
sense to do things this way, and fits with the parenting
method very well.

phobos
Posts: 0
Joined: Tue Mar 09, 2004 5:38 pm

Post by phobos »

Are there any plans to support alternate coordinate systems in a future build? Like a WCS/UCS in Autocad. This way, you could have a "BCS - Blender Coord Space", and a user definable or global world space for translations.

zaz
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Joined: Mon Dec 01, 2003 5:44 am

Post by zaz »

The "Center" of a blender object is sort of a misnomer as its really the coordinate origin. You can set it any place you like, so if you want to work in world coordinates, place the 3D cursor (that little red and white ring) at the origin of the world coordinate system and in the Editing (F9) panel, click the Centre Cursor button.

If you move your object, you wil need to reset this to keep the coordinates. If you move the vertices in edit mode (TAKBEY), the object's origin will stay at the world origin.

BTW, you can scale and rotate around the 3D cursor if you didn't know that, just press the . (period key) or select the 3D cursor from the menu in the 3D View header.

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