How to move an object a fixed distance along one of its axis

A newbie question: In my Update function I want to move a gameObject along one of its axis, by a fixed distance (its own width), irrespective of its World rotation transform.

The value against which I check the gameObject’s width to stop the translate should be the object’s own transform.position.x but this value varies depending on the gameObject’s World rotation transform.

Is there a way to extract the object’s local transform.position.x ie: relative to itself?
Or is there a better way to stop the translate loop at a given value?

This script is dynamically attached to game objects of various dimensions and positions, so the given value has to be from the object’s own transform.

I’m not entirely sure this answers your question, but hitting the low hanging fruit first: You can access an entity’s local relative data by using

transform.localPosition

Some additional notes that may help you: You can also get your object’s relative axes by using the following:

transform.forward; //local Z Axis
transform.right; //local X Axis
transform.up; //local Y Axis