Hi makeit simple,
Thanks for your feed-back, but we miscommunicated. My method is to draw the wall layout on a floor plan. This grid snap allows door openings and window openings in the wall floor plan, such that no blocks have to be cut to fit that door or window opening.
In other words, if I want a doorway opening about 15-feet from a wall corner, then the snap will tell me that the nearest half block increment between the corner and that doorway is 15'-1 1/8", and wont require any blocks cut to fit. In other words, the house floor plan dimensions are adjusted to half-block increments, for the convenience of construction.
Hope this clears the air.