RE: 30mm vs 30.4mm Wheels & Tires
2025-12-26, 5:50 (This post was last modified: 2025-12-26, 5:52 by tom alphin.)
2025-12-26, 5:50 (This post was last modified: 2025-12-26, 5:52 by tom alphin.)
I just wanted to provide a quick update because it is my desire to leverage my experience creating the online and now print versions of The LEGO Parts Guide to feed back to this community and (hopefully) help make LDraw better too.
As you will find, I attached a draft of the chapter for my upcoming book that describes the wheel elements. Of particular interest to this group is the illustration on the bottom of page 84. The additional digit (30.4 vs 30) is actually relevant to the narrative of the book because this is the precision needed to reinforce that most wheels are an even multiple of LEGO units in width. (I define 1 'unit' as the width of a wall, which is 4 LDU. I prefer to use this unit system since it reinforces the core geometry of the brick, plate, and stud.)
LDraw Suggestion: Since the decimal is actually useful in correctly defining the measurements, and since the decimal is often used on other online LEGO resources (bricklink & rebrickable) - my suggestion is to use the decimal on LDraw part names as well. I suspect this would require an official change to the naming conventions for parts.
Please let me know if you have thoughts on my approach in the book, the chapter text itself, or on my proposal to allow one decimal of additional precision for part names.
Sincerely,
—Tom Alphin
As you will find, I attached a draft of the chapter for my upcoming book that describes the wheel elements. Of particular interest to this group is the illustration on the bottom of page 84. The additional digit (30.4 vs 30) is actually relevant to the narrative of the book because this is the precision needed to reinforce that most wheels are an even multiple of LEGO units in width. (I define 1 'unit' as the width of a wall, which is 4 LDU. I prefer to use this unit system since it reinforces the core geometry of the brick, plate, and stud.)
LDraw Suggestion: Since the decimal is actually useful in correctly defining the measurements, and since the decimal is often used on other online LEGO resources (bricklink & rebrickable) - my suggestion is to use the decimal on LDraw part names as well. I suspect this would require an official change to the naming conventions for parts.
Please let me know if you have thoughts on my approach in the book, the chapter text itself, or on my proposal to allow one decimal of additional precision for part names.
Sincerely,
—Tom Alphin