Seams and Walls

UCLA and Oregon fans on their way to Autzen Stadium to cheer on their respective teams, Saturday, October 10, 2026 (all photos by me).
 

On home game Saturdays, I park in the lot at Eugene City Hall (the former EWEB headquarters), cross the Willamette on the Peter DeFazio pedestrian bridge, and follow the path through Alton Baker Park to Autzen Stadium. Somewhere past the bridge, scattered pedestrians turn into a procession: fans clad in green and yellow(1), all moving in one direction, with the giant Oregon “O” on the stadium’s south elevation in prominent view.
 
Christian Norberg-Schulz wrote that meaningful places arise from concrete things and from the ways we move among them. Paths and destinations, routes and goals, help give a place its character. My gameday trek to Autzen offers both quite literally: a route, a destination, and a shared sense of arrival. Yesterday, I joined a temporary alignment of strangers headed toward the same concrete bowl to cheer for our team and root against the visiting UCLA Bruins.
 
I’ve held season tickets for many years. My seat is in Section 17, Row 14, low and near the east end zone. Many of the people around me have likewise been longtime season‑ticket holders. A section of season‑ticket holders like us forms a tribe within the tribe, assembled by nothing more than where each of us landed when we chose our seats.
 
On paper, UCLA’s visit should have tugged at my loyalties. I attended graduate school there but never became a Bruin the way I was, and remain, a Duck. I was older, I lived off campus, and the team played its home games at the Rose Bowl in Pasadena, a long drive from Westwood. So, the Bruin tribe never stood much of a chance. Oregon claimed me as an undergraduate, during the formative, coming‑of‑age years when such affiliations are set. Which tribe claims us turns on place and on timing, often both at once.
 
Every tribe cultivates its rituals, and one of Autzen’s best grew out of a rule. Before each home game, public address announcer Don Essig, the voice of Ducks football for more than half a century, delivers the weather report and closes with a line the crowd now shouts with him: It never rains in Autzen Stadium. In a 2014 oral history interview, Don traced the line to athletic director Bill Byrne’s 1990 decision to ban smoking and umbrellas in the stands. An umbrella suits whoever sits beneath it; the fans behind catch the runoff. Announcing the ban each week, he gradually turned it into the claim that no one needed an umbrella anyway, because it never rains here. A long run of dry home games made the joke seem prophetic. Years later, Don considered retiring the line. He was told it had nothing to do with the weather anymore. By then the phrase belonged to the crowd rather than its author. A rule about the building created a ritual, and the ritual created a fiction everyone inside the bowl agrees to share for an afternoon. Visitors hear an inaccurate weather report. Ducks fans hear a password.
 

The Ducks take the field before the start of the contest. UCLA fans, identifiable by their powder blue garb, occupy the visitors' section.

Why does this kind of tribalism strike me as healthy when so much of what goes by that name does not? I see four conditions. It is voluntary. It stays bounded in space and time, gathering in a vessel built for the purpose and dispersing when the clock runs out. The game operates under rules that both sides agree to play by, however loudly we dispute their application. And its loyalties nest. Don, an Oregon State graduate and one-time Beaver rally king, put it plainly in the same interview: “When the Beavers are playing the Ducks, I’m a Duck.” Otherwise, he roots for the Beavers.
 
Christopher Alexander made the case for something close to healthy tribalism, though he would have bristled at the word; in A Pattern Language, he wanted the city’s subcultures distinct but not “tribal or closed” (Pattern 8: Mosaic of Subcultures). He envisioned a city that accommodates varied ways of life, each with room to flourish, separated by boundaries that also serve as places where neighbors meet. He explicitly rejected ghettos and enforced segregation. Yet the distinction between a boundary that protects a community and one that excludes others depends on more than design. His mosaic presumes that people can choose their affiliations and that the boundaries between them remain permeable. As I’ll come to, Eugene's history reminds us that neither condition can be taken for granted. A boundary may give a community room to be itself, or it may enforce a separation that those on the outside never chose.
 
Of course, the tribe falters at times. Against UCLA, as Oregon turned the ball over seven times and saw its running game stuffed again and again, the crowd booed, and I can’t say the frustration was unearned. After the loss to Oklahoma State earlier this season, online message boards turned on head coach Dan Lanning. Perhaps we shouldn’t be surprised that the worst behavior surfaces outside the stadium. Booing is frustration voiced inside the bowl, and it ends with the game. The tribe sours when it slips its bounds and follows its animosities home.
 
My walk to Autzen passes near the site of a community that lived under very different, far harsher terms. In the 1940s, five Black families (the Reynolds, Mims, Nettles, Washington, and Johnson families) built homes on the north bank of the Willamette, just outside Eugene’s city limits, because they were not allowed to live within them. The settlement became known as Ferry Street Village, or Across the Bridge. In 1949, Lane County razed it to make way for the Ferry Street Bridge. At least 65 Black residents and 36 white residents had to relocate. Most moved to the West 11th Avenue area, which was largely undeveloped and lacked access to sewers or running water. Others moved to Glenwood and the base of Skinner Butte.
 
Racially restrictive covenants were one instrument of the exclusion that helped force Black families to live beyond Eugene's city limits. The deed to the house Lynne and I bought in 1989 had one, restricting its sale to "Caucasians." Our real estate agent brought the covenant to our attention, assuring us a 1948 Supreme Court decision rendered such exclusionary restrictions unenforceable. But that didn’t erase the words on our deed; they reminded us that people once built a wall meant to keep me out of their neighborhood.

Ducks and Bruins leave Autzen together after the game.

 
My other alma mater won, 17–15. After the game, as I walked back through Alton Baker Park, I watched a group of UCLA fans pause on the DeFazio Bridge to take photos against the backdrop of the Willamette River and autumn leaves. A pair of Oregon fans, fresh from a deflating loss, offered to snap their picture. For a moment, the boundaries between the tribes seemed to disappear. I wish the lesson here translated to neighborhoods, but it doesn’t easily. Neighborhoods don’t end at a final whistle. Perhaps the question for those who design and govern cities is not whether to make room for tribes, since people will form them regardless, but whether the edges we draw function as seams or walls, and who gets to decide. 

 
(1)  Oregon is notorious for its sartorial diversity. For the game against UCLA, the UO directed fans to wear black, decidedly not an official school color, but whatever.

Eugene's Proposed Home Energy Score Ordinance

Our house, built in 1952: roughly 1,000 square feet, all-electric, and still without insulation in its exterior walls.
 

Lynne and I bought our house in 1989. It's a modest one-story, three-bedroom ranch, built in 1952, with roughly 1,000 square feet of conditioned space. Soon after we moved in, we replaced the windows, blew insulation into the attic, and laid batts between the floor joists above the crawlspace. More recently, we installed a ductless mini-split heat pump and an electric-resistance water heater. The house is all-electric. The one thing we never did was insulate the exterior walls, which remain as they were in 1952: wood frame, siding, and empty cavities.
 
The City of Eugene is considering an ordinance requiring sellers to disclose their home's energy score. A seller would hire a licensed assessor to determine the U.S. Department of Energy Home Energy Score—a rating from 1 to 10 with estimated energy costs and recommended improvements—and include it in the listing. The proposed ordinance would not require those improvements, nor would it mandate a minimum score. According to the city's project page, a typical assessment might cost $150 to $300. Portland, Hillsboro, Milwaukie, and Bend have similar requirements. The council voted 5–3 in March to begin drafting an ordinance, heard testimony on September 21, and is tentatively scheduled to act on October 28.
 

Image: U.S. Department of Energy, Home Energy Score Scoring Methodology (2021).

 
The score is what DOE calls an asset rating. It rates the house itself rather than how the people inside it live, so houses can be compared on an equal basis. There's a hitch. The model assumes the number of occupants equals the number of bedrooms plus one, so it estimates hot-water use for our three-bedroom house as if four people lived here rather than two. DOE's methodology also fixes the proportions of every detached house at a 5:3 rectangle. That simplification ignores the many houses that are long, narrow, or irregular. A house with more exterior envelope per unit of enclosed volume loses more heat than a compact one of the same floor area, yet the model treats them the same if they have the same number of stories.
 

Three one-story plans of 1,000 square feet each. The score models every detached house as the 5:3 rectangle at top.

 
How would our house fare? Without paying for an assessment, I'd guess somewhere in the middle of the scale. The model reflects total estimated energy use, not use per square foot, so small houses fare better; Earth Advantage's analysis of Portland scores found that homes of 501 to 1,500 square feet averaged 5.2, while those of 2,501 to 5,000 square feet averaged 3.3.
 
The score uses source energy, which includes the energy lost generating and delivering fuel to the house. DOE's national conversion factor for electricity is 2.44; for natural gas it is 1.05,(1) so electricity counts nearly two and a half times as much as gas. Our heat pump, which delivers several units of heat per unit of electricity, roughly offsets that penalty relative to a gas furnace. Our water heater does not. A 90-percent-efficient electric-resistance tank still scores worse than a mediocre gas water heater once the conversion factor is applied, and the model charges it for four people's hot-water use, not two. By my rough arithmetic, it costs us about as much on the score as our uninsulated walls.
 
A home inspector would note favorably that we installed our water heater last year. A home energy score report would likely still recommend a heat-pump model when it's replaced. A heat-pump water heater needs a large volume of surrounding air, or else louvers or ducting, and the closet our water heater occupies offers neither of those. The model can't see every quirk of a particular house. It wouldn't see the old ductwork still connected to wall registers, now buried in our attic insulation, or our fireplace, whose chimney may leak air despite the fireplace glass doors and a closed damper. Only an optional blower-door test would reveal how much air either one lets escape. An inspection tells a buyer what needs replacing; the home energy score tells the buyer what the house will cost to run. Buyers need both.
 
Does the market pay attention to scores when they're required? A study published in Land Economics this July, covering more than 21,000 Portland sales between 2018 and 2021, found that each additional energy-score point corresponded with a price increase of roughly 0.8 percent (about $4,200 on the average home in the sample). The city's staff report states flatly that low-scoring homes do not see reduced sale prices. That goes further than the evidence. If higher scores command a premium, lower scores sell at a relative discount compared with otherwise similar homes. Low-scoring homes sell for modestly less, broadly consistent with their higher expected energy costs, though the largest single step falls between a score of 1 and 2. The market appears to be pricing energy rather than stigmatizing older houses.
 

In Portland, homes sold for more as their scores rose, but the gains came unevenly: a large step from 1 to 2, little change from 2 to 5, then steadier gains above that. It belongs right after the paragraph on the Land Economics study.

 
Enforcement matters as well. Portland, which suspended the requirement during the pandemic and has since favored education over fines, saw early compliance of roughly 55 to 64 percent; Bend, which enforces its requirement, reports 83 percent. Research on Portland finds that sellers of low-scoring homes are less likely to post their scores, so an unenforced ordinance mostly informs buyers about the better houses.
 
Some of the ordinance’s critics raise points worth weighing. At a meeting with staff, one Eugene realtor distinguished between consumer protection and consumer choice. I'm agnostic about this: we accept other mandated disclosures without complaint, lead-based paint being the obvious example, but lead is a health hazard, while energy inefficiency is perceived mainly as a cost. The case for disclosing a cost is weaker, though not negligible, and home sales already carry so many requirements that one more costing a few hundred dollars will not move the needle much.
 
Four local architects who met with staff suggested the score was redundant because architects already explain energy codes to their clients. Energy codes govern new construction and alterations requiring permits. They also noted that a policy triggered by sales never reaches homes that aren't on the market.
 
Councilor Mike Clark, who voted against drafting the ordinance in March but in June voted to send it to a public hearing, has told the Eugene Weekly he wants to keep housing "as affordable as humanly possible" without duplicating efforts. His concern is a redesigned national appraisal form, required for mortgages sold to Fannie Mae and Freddie Mac beginning November 2, which adds a section on energy-efficient and green features. The overlap is genuine. Still, an appraisal comes after an offer is accepted, too late for comparing houses; it goes to the lender, not a public listing; and it describes features without modeling energy use. Cash purchases involve no appraisal at all, and the city's consultant, citing local market data, puts them at roughly a fifth of recent Eugene sales. The two may even work together: DOE's score report includes a reference energy-cost figure intended for appraisers.
 
Advocates tie the ordinance to Eugene's goal of halving community fossil-fuel use by 2030, but the city's own report concedes that disclosure alone is unlikely to deliver significant greenhouse-gas reductions. Three-quarters of Eugene households heat with electricity, most of it hydroelectric, so improving an all-electric house like ours saves money but comparatively little carbon. The carbon is in natural gas, and a fuel-neutral disclosure does little to move anyone off it. The national source-energy factor also treats Eugene's largely hydroelectric power as if it came from the average national grid.
 
Where does that leave me? Mildly in favor of the requirement, with conditions. The ordinance is a modest, relatively inexpensive disclosure measure. Its justification is consumer information, not public health and not, in any meaningful sense, climate. It is worth adopting if the city enforces it as Bend does, and if Eugene's reports reflect local power and rates. It will not pay for a single upgrade, and it will not reach renters or long-tenured owners like Lynne and me.
 
Would seeing the energy score for the house we bought in 1989 and still occupy have changed our decision to buy it? Probably not. More important to us were location, condition, whether it suited our needs, and price. After a long search, our realtor urged us to act quickly, and we did. EWEB's incentives later persuaded us to replace the windows and insulate the attic and floor, projects that were expensive and disruptive. The incentives for insulating the walls were insufficient, and we did not act. We were not awash in money, and I didn't want a home-equity loan on top of our mortgage. Neither cost nor disruption should have stopped us, but they did. The ordinance assumes that information leads to action. We've had the necessary information for thirty-seven years, yet our walls remain uninsulated.
 

*    *    *    *    *    *

If you have strong feelings, one way or the other, about the proposed ordinance, submit your written comments to the city before October 14. You can email them to mayorcouncilandcitymanager@eugene-or.gov or send them via snail mail to the Mayor and City Council at 500 East 4th Avenue, Suite 302, Eugene, OR 97401.
 
(1) DOE's 2021 methodology paper lists 2.56; its current online documentation lists 2.44. Either way, the factor is a national average and does not reflect Eugene's largely hydroelectric power supply.

The Eugene in My Head

Ferry Street Bridge viaduct, looking south (Google Streetview)

 

My parents drove me down to Eugene to drop me off for my first year at the University of Oregon in September of 1980. I remember crossing the Ferry Street Bridge, then the viaduct, and seeing Eugene’s modest downtown skyline ahead of us. As we crested the viaduct at the end of our eight-hour drive, my hungry father spotted Hoots (the old 24-hour diner at 8th and Mill) and decided that was where we would have a late lunch. Nothing about that moment was dramatic or postcard-worthy; its ordinariness is exactly what fixed it in my memory.
 
At the time, I had no reason to think that Hoots would eventually disappear, or that a massive student housing development would occupy its site decades later. I sometimes wonder what my 20-year-old self would think if I could somehow put him back in the same place today. He might be surprised by the new luxury student housing towers that now punctuate the vista, or by the downtown riverfront transformation (once EWEB’s utility operations yard, now becoming an active and accessible new neighborhood and park). Still, I suspect he would recognize Eugene immediately. If anything, he would be surprised that, years later, the city would become his permanent home.
 
My first Eugene was actually a very small place. I didn't have a car, so I got around by bicycle. I lived at the University Inn (now Barnhart Hall) on Patterson Street and spent most of my time on campus or in the West University neighborhood. The pedestrian-scaled stretch of 13th Avenue was part of that early orbit, although it has since been razed twice, first for Sacred Heart Hospital and more recently for a new student housing development. I considered anything beyond that vicinity relatively remote. Once classes began, I had few reasons to leave the immediate area. Visiting far corners of the city, or even downtown, felt like traveling to another planet.
 
I left in 1983 following graduation and eventually returned in 1988. By then I had been back to Vancouver, gone to UCLA, worked in Los Angeles, returned to Canada, married, and accumulated enough intervening life that I might reasonably have expected Eugene to feel like a place I only had once known. Instead, I felt like I'd never left. I went back to work, settled into a house, and resumed spending time around the University. It felt less like returning to a former home than continuing something that had merely been interrupted.
 
I don't remember a particular moment when Eugene began to feel like where I truly belonged. It happened gradually, and I think I first noticed it after one of my visits to Vancouver: I remember returning to Eugene and being struck by how calm the traffic seemed. What counted as rush hour in Eugene would barely have registered in Vancouver, where driving could often be a white-knuckle exercise. At some point, without thinking about it consciously, I had come to appreciate Eugene's relative quiet and smallness. What had initially seemed somewhat underwhelming had become familiar, and familiarity had gradually become attachment.
 
Lynne and I have lived in the same house since 1989, and the street we’re on has changed very little. The most obvious change is the maple tree in our front yard that was barely more than a sapling when we moved in. Today it is a substantial tree with a broad canopy. The house and the street have remained almost unchanged while the tree has recorded the passage of time. Obviously, the city has changed. Buildings have come and gone, the population has grown, and places that were part of my early Eugene have disappeared while others have been altered beyond recognition. Traffic is heavier, and some of the city’s problems are more visible than they once were. Yet, to me, the city doesn't feel fundamentally different.
 
I think that has something to do with the mental map I formed in 1980. It has never really been replaced; it has simply been added to. New buildings and businesses have become new layers on top of the old map. Streets have acquired different buildings, businesses have disappeared, neighborhoods have changed, and new places have become familiar, but the underlying sense of where things are has remained remarkably persistent. Willamette Street, for example, still feels central to me, much as it did when it was the “Gut” back in the day. That doesn't mean I know every corner of the city. After all these years, Lynne and I recently found ourselves driving Goodpasture Loop for the first time simply because we'd never bothered to see where it went. It turned out to be a pleasant discovery.
 
Vancouver has taught me something similar, although in a somewhat stranger way. I have been away from it since 1988, and the city has changed enormously since then, yet whenever I return, I still experience the odd sensation of being home. In recent years, Lynne hasn't accompanied me on my trips north, which makes the sensation even more pronounced. For a few days, I seem to slip back into another version of my life, one in which Vancouver is where I live and Eugene is somewhere else. Then I return to Eugene and the arrangement reverses itself. It is almost as though I occupy two alternate universes, each of which feels completely real while I'm in it.
 
That may be part of what makes a place familiar. The Eugene I first met at twenty is not the Eugene that exists today, nor am I exactly the person I was then. But neither feels entirely separate from what I remember. The years have accumulated, the city has changed, and the earlier Eugene is still there in the way I experience the place. Maybe that's why, after all these years, the Eugene in my head still feels so much like the place I first saw from the Ferry Street Bridge.

S Tier Sewers, F Tier Feelings

I spent plenty of time during my working years sitting in hearing rooms where citizens stood at a microphone to explain at length why a project should not be built. Eventually, their objections fell into recognizable patterns, which I now realize I can sort into tiers, not unlike the ranking meme teenagers use for video game characters. I offer this metric half-jokingly and half-earnestly; I think I’ve earned the right to use it here to highlight an issue endemic to public hearing processes.

 
Tier lists run from S ("Superior") down to F ("Worst"). I’m ranking the objections neighbors raise against urban infill not by how sympathetic they sound but by how much they reveal about real issues. A B‑tier objection can be perfectly valid and still serve as cover for something further down the list.
 
Here are the tiers:
 
S Tier: Infrastructure Capacity
Sanitary sewer, water mains, stormwater management. When someone says the existing line can't handle the load, that's a testable engineering claim, not a feeling dressed up as a fact. These arguments can kill projects, and sometimes they should. Real historic preservation belongs here too, but only if there's a documented resource at stake, not simply something old.
 
A Tier: Documented Safety
Traffic conflicts, pedestrian risk, and genuine scale transitions at zone edges. These objections point to intersections with actual crash histories or to proposals that drop five stories onto a block of single-story houses with no buffer. They warrant real debate; neighbors are often in the right.
 
B Tier: Real Issues, Routinely Misapplied
Parking, shadow studies, tree canopy loss. These are legitimate design considerations, but detractors deploy them as categorical vetoes regardless of whether the specific project deserves rejection. The concern is real in the abstract and often misapplied in practice.
 
C Tier: Dressed-Up Preference
"Neighborhood character." Unlike parking, character rarely gets defined before someone invokes it. In my experience, the definition shifts depending on who proposes what: a duplex threatens character; a McMansion, somehow, does not.
 
D Tier: Coded Objections
The "wrong kind of people," phrased as politely as possible. These objections are rarely said outright. More often, it’s cloaked by whatever euphemism fits the day.
 
F Tier: Property Values, Undisguised
No argument attached. Just fear. Occasionally someone outright admits this is the sole basis for their objection; more often it rides inside one of the tiers above.
 
The tier list is neat on paper. In practice, the tiers converge. I learned that firsthand on one of my projects.
 
Back in 2013–2014, I worked on a developer’s proposal for nearly fifty student-housing buildings across a steep, tree-covered hillside under the city's discretionary PUD process. My firm's assignment was narrow: design the buildings and testify on visual impact, scale, and compatibility with the property’s hillside setting. It's easy to prosecute NIMBYs from the outside; it's harder to admit that I sometimes served as counsel for the defense. My role put me at the microphone to answer the neighborhood's strongest objections. They argued the project violated hillside protection goals, encroached on a protected ridgeline, and required clear-cutting century-old oaks and Douglas firs. I testified that our team arrayed the buildings sensitively, mitigated visual impact, and respected the ridgeline.
 
Did I believe every word of my testimony? Yes, on that day, I thought it was defensible. Whether I offered the most candid answers, I'm less sure now. The neighbors did bring substantive concerns about geology and canopy loss. I remember feeling a mix of professional obligation and faint unease as I listened, unsure whether I was hearing genuine alarm or simply the familiar cadence of public opposition. The Hearings Official weighed every voice against the PUD criteria and ultimately denied the project. On the merits that really mattered, the neighbors were right, and the process worked.
 
But alongside those legitimate arguments, a more specious complaint surfaced about the kind of residents the project would bring: fewer families, more students. That coded objection belongs squarely in D tier. It wouldn't have survived scrutiny on its own. The reality is it didn't need to because it traveled beside arguments backed by real science and policy, and nobody in the room—me included—separated it from those valid concerns.
 
Public hearings compress every argument into the same few minutes at the same microphone. A Hearings Official can weigh a claim about slope stability against the record and rule on it. The hillside objections deserved and received a full hearing. Should anyone in that room have separated the coded objection from the legitimate ones? I didn’t, and I’m not sure the structure of a public hearing allows it.
 

A Diagram's Work

The Vancouver House by Bjarke Ingels Group (BIG), a diagrammatic form rendered at full scale and in real life (my photo).

I participated in a review of student work this past Wednesday at the University of Oregon, one of several summer studio reviews I've sat in on this year. A faculty member and I reviewed a pair of projects—an admittedly small sample—that between them captured two versions of the same issue. One student's presentation had no site analysis or parti diagrams of any kind. The other's did, but they read as an afterthought, drawings that explained the finished design rather than ones that had helped generate it. I've noticed the same in previous reviews; even when an instructor explicitly requires process diagrams, what is pinned up still looks reverse-engineered. The problem lies in the diagrams' provenance—a reality that holds true whether they are the work of students or some of today's most celebrated firms.

Stan Allen, the architect, theorist, and former dean of Princeton's architecture program, drew a useful distinction in a 1998 essay: a diagram's job isn't to depict a building. It's to work out relationships—between program and form, between one space and another—before the building exists to depict. As Allen puts it, diagrams are "architecture's best means to engage the complexity of the real." Much of what gets called a diagram does the opposite: it reverse-engineers a graphic summary after a decision has been made, rather than helping to discover it. A generative diagram precedes the decision. It doesn't explain the building afterward; it's part of the process by which the architect finds the building's basic idea in the first place.

There's a simple test for telling the difference. Point to a particular move in the finished design and ask the student to trace it back to the diagram. Not necessarily to an identical mark, but to something in the diagram that participated in the sequence of decisions that produced it. If they can do that, the diagram probably played a generative role. If they instead begin explaining the diagram in terms of the finished building, the odds are good that the diagram came later. A generative diagram doesn't have to predict the finished design, only to have been capable of changing its direction.

Early design diagram for the VA Roseburg Protective Care Unit. The courtyard organization survived; the entry gesture did not.

The old sketch above passes this test, with qualifications. I drew it during my earliest analyses for the design of the VA Roseburg Protective Care Unit, as I attempted to match site, program, and intent. (I covered this project's design process in my "A Case Study" series of posts.) It's clearly rough: hatched masses standing in for building volumes, a loose unhatched void at the center indicating a courtyard, and an arrow driving in from outside the frame toward one corner.

The courtyard organization held. It became the wrapped, mirrored heart of the finished design, anchored by a huge mimosa tree that I likened to the proverbial Tree of Life. The arrow, on the other hand, didn't hold. It was a stand-in for a real, unresolved question: how to control entry into the secure courtyard. What ultimately emerged wasn't a refinement of the arrow's gesture. It became an entry pavilion, akin to the Propylaea at the Acropolis.

Site plan for the VA Roseburg Protective Care Unit.

That's the important distinction. The diagram didn't predict the building. It put a problem into play while the design was still unsettled enough for the problem to matter. One part of the sketch survived almost intact; another led somewhere I hadn't anticipated. Both were useful because they helped determine what came next.

This tension between diagrammatic exploration and graphic presentation persists in contemporary practice. Bjarke Ingels has described how his firm, BIG, uses diagrams to track the reasoning behind design decisions, a practice he developed in part while working under Rem Koolhaas at OMA. MVRDV's Farmax, published around the same period as Allen's essay, made particularly explicit use of diagrams as instruments of form-finding.  

BIG's series of conceptual diagrams for their Vancouver House project (source: htttps://big.dk/projects/vancouver-house-missing-pictures-7130)  

Yet, there remains a persistent ambiguity in architectural representation: a diagram can document a process, or it can be made to look as though a process existed. Critics have sometimes read BIG's diagrams less as records of discovery than as clever post-rationalization of forms arrived at by other means. The distinction matters because a diagram can be perfectly convincing as a graphic artifact while having had no meaningful role in producing the design.

AI makes that distinction more consequential. Current tools can generate massing alternatives, test code and zoning conditions, manipulate models, and produce images that would once have required considerable effort. Those capabilities may become useful parts of conceptual design. The more immediate problem is simpler: AI can also produce polished, diagram-shaped images on demand. It becomes all too easy to manufacture the appearance of a rigorous design process after the fact.

The issue isn't whether an AI-generated diagram is legitimate because a person didn't draw it by hand. A computer-generated diagram can be every bit as generative as a pencil sketch if it helps identify a consequential relationship, tests an idea, or changes the direction of the design. What matters is what the diagram does in the sequence of thought. A diagram that merely gives graphic form to a conclusion reached some other way is still an afterthought, regardless of who, or what, made it.

Generative diagram by MVRDV for The Modernist, a mixed-use project in Rotterdam (image source: https://www.mvrdv.com/projects/308/the-modernist)  

This is also why a diagram's graphic appearance can be misleading. Arrows, bubbles, hatching, color coding, and other conventions can make a drawing look diagrammatic without telling us anything about its role in the design process. Resembling a diagram isn't the same as having done a diagram's work.

The student who left diagrams out of the presentation wasn't hiding anything, and the one whose diagrams read as afterthoughts wasn't trying to pass off invented process as real. Both, I suspect, simply hadn't yet learned the purpose of diagramming during the early phase of project conceptualization. That's a lesson AI tools may make easier to skip, in a studio or in a firm, because they can cleanly simulate the appearance of analysis without requiring the heavy cognitive lift of the analysis itself.

The afterthought diagram is the more instructive case because it looks like it's doing a job it isn't. Whatever insight it might have delivered—what relationship was worth testing, which constraint should organize the plan—was available only while the design was still unsettled enough to need testing. It can still look flawless on a presentation board, but what it ultimately lacks is a place in the sequence where it still had the power to change the outcome.