Line Weights, Stochasticity, Logs(√2) and Natural perception
A few weeks ago I was listening to Stochasticity | Radio lab (https://radiolab.org/podcast/91684-stochasticity) podcast. Stochasticity is a mathematical term that refers to a variable process that is characterized by some randomness and uncertainty and the podcast went into what humans think is random really isn't. Forensic accountants can tell when someone is cooking books by how many times 0 through 9 appears in the numbers and how many times adjacent numbers appear. I won't spoil it but it isn't what you think.
In this podcast they mentioned Lisa Pollack in the Financial Times of 23 December, where studies have been performed on babies perceptions of numbers. https://mathsmartinthomas.wordpress.com/2014/12/25/babies-number-sense-is-logarithmic/
Apparently before we are forced to learn 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 we innately understand doubling as a spike in activity in the parietal lobe of our brain.
I started looking at my company standards for line weights and was looking to mesh all our groups into a common standards and I looked back to the ISO standards and ran across Paul Munford's CAD Setter Out - particularly for the TECHNICAL DRAWING STANDARDS: LINE WEIGHTS section. In there he mentioned
...the ratio between Line weights is 1:√2 (≈ 1:1.4)
and it clicked- mind blown. There may be a trick or a mind hack to good line weights and discernibility in drawings. Something they never taught us in Mississippi State School of Architecture back in the 1990s - and what feels and looks 'natural' with those pen weights and pulling those KohINoor pen sets.
The ISO standard is based on using 3-4 pen weights for a particular drawing at a given scale. Narrow(0.13mm), Graphical (annotation 0.18mm) and Wide(0.25mm) followed by a skip to the next "Extra Wide"(0.500mm) value.
Ching describes pure line drafting weights as a means to discern depth:
An in my experiences and what I have learned, We have the need for heaviest to lightest relative line weights for
6 Section cut ground plane
4 Outline of the envelope
3 Elements cut within the envelope
2 Elements beyond the cut plane
1 Pattern work
2 "Beyond" line work - which is typically a very thin line or a Half Tone fine line representing far away elements.
2 or 1 for annotations and 4, 3 or 2 for leaders depending on how heavy you want your leaders attaching text to information is read (Is it dominant or is is subdued to allow the graphics to the forefront)
The ISO standards align with those old mechanical pen sets and the NCS standards which BTW is Revit Out Of The Box (OOTB)
Then the scales shift the applied line weights up or down to give the lines more presence in the finer details (As we approach 1"=1" or 001xp) out to the coarser plans and sections (1"=20' or 240xp).
As long as the 'bank' of line weights is proportional between each pen weight the relative maps can be applied accordingly. Revit allows for these mappings to be adjusted depending on which defined scale is closed in the lineweights and the entire block can be shifted up or down compared to the relative pen number.
Can't wait to see this applied to see if it turns out well or not!