Sign in to follow this  
Alundra

Translation and Position terms

Recommended Posts

Alundra    2316

Hi,

I actually use "Translation" for all related to matrix (matrix,transform,decomp) and "Position" for all other things.

Sometimes I think about change all "Translation" to "Position" to have a consistent name everywhere.

What do you think about that ?

Edited by Alundra

Share this post


Link to post
Share on other sites
alvaro    21263
I geometry "translation" means a transformation that maps point P to point P + T. I don't think "position" has a formal definition, but I think I would normally use it for the point in space where an object is placed and the object's attitude. Edited by Álvaro

Share this post


Link to post
Share on other sites
Norman Barrows    7179

translation: movement in the x,y,z directions. the translation portion of a transformation matrix.

 

position/location: technically a point in 3-space. In caveman 3.0 a "location" includes a setting (outdoors, cavern, etc), map square coordinates, a 3D point in the map square, and an orientation.

 

orientation: a 3D direction vector and roll, possibly described by eulers or a quat or other means.

 

to be precise, you should think in terms of scales, combined with orientations and positions/locations, to create transforms.

 

it would be nice if there was a term for location + orientation, but there isn't really - at least that i'm aware of. "attitude" comes to mind, but that's usually just considered to be an aviation term for "orientation".

Share this post


Link to post
Share on other sites
Norman Barrows    7179

it actually really gets fuzzy.

 

i've heard "orientation" used to refer to translation plus rotation as Alvaro says.

 

i've also heard of "location" as translation + rotation.

 

and of course "position" as translation.

 

but there's little confusion about the terms transform, translation, rotation, and scale.

 

that's what makes those terms ( used correctly ) a pretty safe bet.

Share this post


Link to post
Share on other sites
LorenzoGatti    4449

There's a fundamental difference between positions (which might or might not include an orientation) and transformations which can be applied to a position to get another position. Transformations have a group structure (they can be composed with one another to get another transformation), in common cases even a vector space structure (e.g. typical 4*4 matrices) while positions don't have useful operations giving other positions (finding the transform which maps one to the other or finding their distance give values of other types).

Even if you represent positions and transformations in an apparently similar way (for example x,y and z coordinates for points in a 3D space and displacement along three coordinate axes for translations) pretending they are the same thing causes only confusion.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this