Projection Study Thoughts
Given the exponential increase in perceived visual compression with each degree of rotation from the central vision axis; structures with equal offsets should present similar proportions throughout various viewing distances, vertically dominant structures should present a moderate loss of height in close proximity and horizontally dominant structures would appear to narrow 
and present the largest proportional shift of the three. The range of viewing distances for perceived compression would be dependent on the range of an individual’s peripheral field and the size of the structure.
Barbara’s pergola is a very reactive shape with 11.5′ to the left, 11.5′ feet to the right and only 6.75′ above the central vision axis. My perceived narrowing reached a surprising 14.1% at approximately 3.75′ away, a 144 degree cone of vision. The structure continued to seem narrow at closer distances but, I no longer experienced the work as a whole…only portions of it.
Other Factors Affecting Reactivity
Context – The pergola is a dominant feature in its landscape, however, it is predominately experienced as a background piece…one lingers in its shade to watch tennis. This contributes to a longer duration of peripheral exposure compared to the acute view experienced during the approach walk. 
This preponderance of peripheral experiential memory may reinforce a belief that the structure actually is narrower.
Texture – The pergola’s open frame has many edges and tonal planes that stimulate a higher than usual level of peripheral field processing. This increased brain activity will reinforce memories of compressed views that we believe to be the ‘true’ experience.
Movement – The tennis deck is built over a reflecting pond. With light waving across the pergola’s beams and foliage moving in the breeze…the pergola can become a distinct and visually active place. Again, this level of visual stimulation likely increases associative memories that support a compressed mental image while any acute vision non-compressed views are of only portions and lack the context to edit the impression of the full structure.
Why did I undertake this study?
The deck was designed to view tennis…the pergola for shade. In design refinement, the wide open space under the pergola seemed perfect for showing off the pendent Wisteria 
flowers…experiencing the narrowing of this space was disappointing.
Projection Tool Application
Given a continuation of the projection tool arcs, the tool can generate proportional shifts beyond the range of my experience pointing towards a viewing distance where the maximum is reached and an easing of compression begins. This was surprising but, makes sense as the pergola apex begins to reach retinal fields with more aggressive compression angles and the compression progression begins to level off at the extreme limits of the retinal curve.
The wall of my den was used in a projection tool test. Actual dimensions of 14′ 8.5″ by 8′ 10.375″ were viewed at distances of 8’9″ and 4’8″ – projecting proportional shifts of 2.6% and 10.2% respectively. So far others have stated their perceived proportions of the wall to be similar to the tools projections…but, find the act of “seeing without looking” to feel a bit odd.