8 March 2011
mineralogical notes
and making stereoscopic drawings
image above : non-crystalline tetrahedral network model, from "a simple method for making stereoscopic drawings" by fred ordway, the american mineralogist, vol 50, september 1965. this image pair is made for viewing with a stereoscope.
a 3-page scanned article is included below. in this 1965 article, a molecular-scaled geological representation technique is explored - stereoscopic drawing. it is a fascinating, technical account of an experimental drawing method, which aims to overcome the otherwise slow process a crystallographer must endure to produce such a stereo-pair image.
article : "a simple method for making stereoscopic drawings" by fred ordway, the american mineralogist, vol 50, september 1965
stereos - stereós, meaning solid
the particular things, from this article, which i'd like to do something with are:
the necessary 4 coordinates and stereo pairs,
parallax mining - to find atomic/molecular structure,
parall-axis - the problem of vertical vs horizontal parallax with regards to human visual perception and interocular distances.
the necessary 4 coordinates and stereo pairs,
parallax mining - to find atomic/molecular structure,
parall-axis - the problem of vertical vs horizontal parallax with regards to human visual perception and interocular distances.
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article : "a simple method for making stereoscopic drawings" by fred ordway, the american mineralogist, vol 50, september 1965
stereos - stereós, meaning solid
-scopic - skopion, meaning to look at
the cinema screens in recent times have seen a notable rise in 3d films - the movie-makers are sharing the same basic principles as this crystallograpgher's notes; human stereoscopic vision. simply put, we have one eye about 6cm horiztonally adjacent from another eye. this is called the interocular distance. healthy humans also, crucially, have the phenomenal ability to fuse the two images we experience from each eye - visual-depth perception.
some people are not able to view our world with stereoscopic vision - perhaps the neurophysiology is affected by some disorder, the eyes do not sufficiently look in the same direction or some other issue. recently i found myself reading a fascinating, almost frightening book by oliver sacks entitled the mind's eye. in this book a woman named sue, who, for most of her life had only monocular vision, suddenly is able to see in binocular vision
"i noticed today that the light fixture that hangs down from our kitchen ceiling looks different. it seems to occupy some space between myself and the ceiling...
i noticed the edge of the open door to my office seemed to stick out toward me. now, i always knew that the door was sticking out toward me when it was open because of the shape of the door, perspective and other monocular cues, but i have never seen it in depth"
quote : the mind's eye, p129, oliver sacks, 2010
it is not only likely that we all take for granted the effect of stereoscopic depth, it's wholly improbable that we could even imagine, at will, the world of monocular vision. between ordway's mineralogical representation techniques and sack's patients, quickly questions arise about the limits of our sense of visual-depth, about how we might use this understanding of our eyes and mind to positively inform and create in our "ocular-centric world"
image above : from the above mentioned mineralogical article. i have made an animated gif to simulate the effect of seeing both stereo-pair images at the same time through a stereoscope
[thanks to wales for introducing me to this article. i believe she came across it while panning for diamonds]
[thanks to wales for introducing me to this article. i believe she came across it while panning for diamonds]
Labels: depth, drawing, parallax
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