Blueprint Appreciation Post

Technical drawings are the thing that made this Hogwarts project possible, full stop. I don’t remember which of these was the correct order of events:

  1. I stumbled upon some blueprints online and thought, Wow, I could actually do a 3D model investigating the changes!
  2. I thought, Wow, I’d really like to do a 3D model investigating the changes! and subsequently found some blueprints online.

But either way, I don’t think I ever would have started this thing without some floor plans to guide me.


For the first film, I’ve got two different scans of a single plan of the miniature. One is a high-res B&W scan; the other has much lower resolution and a tighter crop, but it’s in color. Interestingly, their perspectives don’t match, suggesting that one or both of them may have actually originated as photos, not scans. But regardless, here I’ve tried to align them together, applying the low-res color data to the high-res scan. I’ve also rotated it (to match the plans for the other films) and corrected the perspective.

I have a few observations. First of all, this is evidently the fourth revision, dated January 14th, 2001, but there were likely other revisions after this. I say that because this plan is not completely accurate. Flaws I’ve noticed:

  • The Great Hall balcony has the wrong shape – the corners are square and it doesn’t wrap around the north side of the structure.
  • The training grounds tower doesn’t indicate the circle tower where it meets the Durham courtyard structures.
  • The quad interior has the wrong dimensions.
  • The walkway along the east side of the quad exterior appears to have a single level, and the elevation is marked as (I believe) 220′. This is the same level as the adjacent stone bridge. The final design for the first film moves the walkway lower down, with the part nearest the bridge even lower still. This also calls into question the accuracy of the area north of the quad, for which I sadly have no adequate photo reference.

Still, this is an absolutely invaluable look at the original castle.


Sadly, I have no floor plans for the miniature in the second or third films. I very much appreciate Warner Bros. posting these Prisoner of Azkaban elevations at the Studio Tour in London, though:

These cover many of the main changes to the castle in that film, and they were the reason I started my project with the Azkaban castle.


Goblet of Fire is an interesting one. I do have one partial floor plan, but the whole Great Hall/boathouse area is all wrong, as is the quad interior. I suspect that one wasn’t the final revision either.

As you can see, this consists of two scans or photos overlaid on top of each other. This composite I did not do – this is how the image was posted by user “decat” at the RPF.

This drawing provides evidence for the quad cloisters still existing in POA. Presumably, they were still part of that version, and at the time this drawing was created, they simply hadn’t yet decided to raise the quad, add the new arch, remove the cloister and fountain, etc. This is also the only plan I have of the training grounds tower from the COS redesign, and of the adjacent pathway that would eventually change in HBP.


I have no drawings of the miniature from OOTP. Fortunately, not much changed, and the changes that did occur will be easy enough to replicate with help from photogrammetry measurements.


The final HBP floor plan was actually released by Warner Bros. in the book Harry Potter: Page to Screen. It’s a two-page spread, which is wonderful for being able to read all the writing, but it does put an unfortunate seam right in the middle:

Still, it’s a fabulously detailed view of a critical production document and I’m grateful for it. I’m not aware of any inaccuracies here.

The same can almost be said of the earlier version on display at the Studio Tour:

The odd tapering crop is the result of perspective correction, since the original photo was taken at an angle. Note the lack of even the small HBP training grounds tower, the dotted outline of the old DADA tower to be removed, and the more detailed plan of the new astronomy tower.

If that’s not enough for you, though, don’t worry – when it comes to the astronomy tower, MTV News has your back! (Of all sites!)

I haven’t built the astronomy tower yet as of this writing, but this drawing is going to make it a cinch.


The main DH floor plan has also been officially released, albeit with some photo overlays that obscure some of the writing:

That film’s substantial changes are on full display here. The Fantastic Beasts castle is virtually identical; if they did create any drawings for that one, I haven’t seen them.


The real danger in studying these closely is that they refer to all the countless detail drawings that have not surfaced, and likely never will. Always leaves me feeling like the proverbial mouse for whom that cookie was simply not enough.

But ultimately, there’s a real beauty in all these drawings, even if I always find myself wanting more. I’m grateful to the deeply skilled drafters who brought these to life, and to the folks who’ve made them available to us fans!

Starting the Back Cliffs & Ravine

We’ve now got four chunks of Hogwarts’s original terrain finished. In my model, they’re divided as follows:

The blue chunk below the viaduct entrance is separate from the purple chunk below the Long Gallery because the blue chunk was redone in Goblet of Fire. The gold and green chunks on the other side could have been combined with each other and/or the blue chunk, but separating them improves sculpting performance.

The next chunk I added was a small patch that’s exclusive to Prisoner of Azkaban. They slightly built up the area just beneath the corner of the Great Hall, giving it a slightly different profile. (All of this terrain had to be redone when the Great Hall was shifted in Goblet of Fire, but the redesign was more similar to the POA version than to the original.)

Sorcerer’s Stone on the left, Prisoner of Azkaban on the right:

Another view:

But there were bigger changes in POA, of course. When they added the clock tower, wooden bridge, and so on, the surrounding terrain was totally redone. So in creating the bluffs that originally led down to the lake back there, I have to be able to swap them out with the POA version without affecting the adjacent terrain (shown in green above).

Techniques here are the same as what we’ve already seen, although it’s interesting to see the updated rock textures (sans moss) on the base mesh…

This is where photogrammetry stops being useful and I just have to closely study the few available reference images. (Blueprints aren’t super helpful either, since the terrain only follows them very, very roughly.) Another complication is that some VFX shots actually cut off parts of the miniature, particularly in this area; in those cases, I’m trying to treat the complete miniature itself as canon.

More base mesh:

No, you’re not crazy – the mesh protrudes right through the walls of the terrace in some spots. That’ll be fixed soon enough; it’s not hard to shave off excess landscape.

What’s going to be harder is the ravine between the two halves of the castle. That’s where even photo reference starts to dry up, at least for this original version of the castle. Photogrammetry from the big overhead shot in Chamber of Secrets will help me with the north side of the ravine, so I decided to work on that before trying to tackle the south side:

Meanwhile, around the front side, I’ve finally added the tiny lower walkway that seems to curve through the base of the stone bridge:

Sadly, I still can’t find any clear, reliable, pre-POA information on where exactly that walkway goes on the other side of the bridge. I’m starting to think that the one available SS-era floor plan of this area isn’t accurate.

This post is getting long…I’ll save further progress for the next one!

Hogwarts Landscape Strategizing

Today’s post is mostly a big block of text, so let’s at least start with a few random renders of the project so far:

The viaduct area in Prisoner of Azkaban
The Transfiguration courtyard in Prisoner of Azkaban
The Alnwick Castle-based training grounds in the first two films

Now for some words! Lots of them!

So up till now, my castle models have been floating in the air, hundreds of feet above the lake. But I’ve hit a major milestone in the project: I’ve begun creating the rocky landscape the castle sits on!

Here are some factors informing my approach:

  • Many of the films have shots that repurpose views from previous films. These create significant inconsistencies within individual films. I’m disregarding them altogether.
  • At least for the first six films, the environment really has to be treated as two distinct entities:
    • The terrain that surrounds and supports the main 1:24-scale castle miniature.
      • This terrain was carved out of polystyrene, with rocky outcroppings of plaster molded from slabs of coal.
      • This terrain is quite consistent within each film and changes incrementally between films.
    • The lake and mountains that surround the miniature in the films.
      • Typically, the visual effects team integrated photography of Scotland into digital matte paintings and layered those onto 3D geometry.
      • Unlike the miniature, these CG environments change drastically from one scene to the next, not to mention from one film to the next. (The second film contains a particularly dramatic example: there are two establishing shots that use similar or identical plates of the castle miniature, but the surrounding terrain is totally different.)

The upshot is that you can’t create one single environment that will be 100% consistent with every shot in a given film. You can do it with the miniature, but beyond its borders, it’s literally impossible. So my approach there will be impressionistic. Still, I gathered reference images from each film. I carefully took note of common features between films and annotated them with color coding. I even had fun unrolling some of the panning shots into rough simulacra of the original matte paintings.

But you can only do so much researching and strategizing. Eventually you’ve just got to get started! So I hit the major milestone of starting to model the landscape a few days ago…but I’m going to save the renders for the next post. I should have a video for you as well. Doesn’t look like much yet, but the work has started; I’m just having to pace myself right now because of my repetitive strain injuries. But I didn’t want to go too long without at least posting something.

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Continuing the Curtain Walls

Relatively short post today. We’ll start off with some orthographic views of the POA model, by request. This is the state of the model before the progress you’ll see later in this post.

I always enjoy these blueprint-style perspective-less views.

Anyway, onward to today’s update. Let’s start fleshing out the remaining walls surrounding the training grounds! I’m kinda doing the COS version, since most of this is covered by a new hillside from POA onward, but that’s okay.

I hadn’t touched this area since late March 2019…crazy to think that it’s now been over 2 years since I started this whole project!

There’s not a lot of reference for this area of the miniature, but I have found some shots. Between those and photos of the real thing at Alnwick Castle, I think my results are pretty accurate. Interestingly, that guerite (small lookout tower) closest to the camera seems to have been slightly redesigned partway through the construction of the model. I’ve gone with the final design that was glimpsed – if only barely – in the films.

The next structure along the walls is Alnwick Castle’s barbican and gatehouse. (This is the building from which Neville falls and breaks his wrist in the first film.) I had already done a bit of work on this structure as part of an early attempt at recreating Alnwick itself – here’s an old render from this post:

I built this to the same scale as the main Hogwarts model, so it was easy enough to drop that into place and add brick textures:

As we’ve seen with other areas, I’ve built the walls so they go quite a ways down. From this view inside the training grounds, the lowest parts will eventually be covered up by grassy lawns. But on the outside, the terrain is rocky and uneven, and in some areas it slopes downward to reveal the lower areas of the wall. It’s easiest to just make the walls really deep and then cover a lot of it up with the terrain later on.

Fortunately, there are some nice orthographic drawings of the barbican/gatehouse structure on a placard at the location. These provide some very helpful reference. As always, my goal is to capture at least one of these, in roughly descending order of importance:

  1. The onscreen appearance and imagined reality of the castle in the films (which is achieved through a mixture of location shoots, miniatures, CGI, etc.)
  2. The main 1:24 scale VFX miniature of the whole castle
  3. The corresponding real-life filming location

These do not always agree, and there are significant gaps in the reference for the first two, so finding the right compromises can be tricky. For instance, this shot in Sorcerer’s Stone shows Neville’s POV as he nearly impales himself on a statue:

I’m not sure about the background, but the foreground architecture is all CG, and it matches neither the real-life location nor the miniature…although the corresponding spots at the location and on the miniature are never shown onscreen. To make matters worse, in the live-action location shots that follow, the statue (which I believe was installed just for the film) has moved to a different corner of the structure. So there is no single coherent reality for me to replicate.

In this particular case, my approach will be to ignore this quick shot altogether and aim instead for the real location with the added statues and other set dressings. But I’ll save that for the next post.

COS-OOTP Training Grounds Tower, Cont’d

Whew, sorry for the long delay…the months of sitting at my home desk have taken their toll on my arms, and I’ve had to significantly limit my computer use. This will be a shorter post as a result. I’m starting physical therapy soon…if you’re feeling particularly generous and you want to help support my recovery, my Venmo handle is @Joe-Cardello, for what it’s worth. 🙂

Anyway, let’s continue with the version of the training grounds tower that was seen throughout the middle of the Potter series, including Prisoner of Azkaban. As we work our way around to the west facade, my reference material becomes even scarcer, but I’ve got just enough to piece it together in a reasonably accurate way. I started with plain walls, deciding to add the windows and so forth later:

Here’s a view from overhead once I’d roughed in the main shape of the building. At this point, I wasn’t worried too much about cleaning up the intersections between walls and objects…I just wanted to make sure the layout made sense three-dimensionally:

You can see just a bit of the tiny courtyard in the middle. That’s one area for which I truly have zero reference (other than the basic floor plan). It roughly corresponds to the cobbled inner courtyard at Alnwick Castle, which was actually used in the location shoots for the first film, but the version in the miniature is much smaller and it has a different shape because of the way the Alnwick floor plan was reconfigured around it. So the layout of any doors, windows, or other decorative elements on that part of the miniature sadly remains a mystery.

As I said, I have less progress to share because of my ergonomic issues, not to mention the simple fact that this is a tricky structure to figure out. But I’ll at least fill out the rest of this post with an aerial overview of my POA castle so far:

Take care of your body, take care of your mind, and don’t be an ass to people who identify as transgender. See you soon!

Starting the Training Grounds Tower

Holy crap! I can’t believe we’ve arrived at the final major tower of Hogwarts! I’ve been eager and afraid to tackle it because of its complex geometry and the limited reference available. Let’s jump in!

The training grounds tower was added to the original castle out of sheer necessity. Alnwick Castle was used as a major filming location so they needed it to be present in the miniature. Stuart Craig’s team tweaked its footprint a bit and built it up into a much taller complex of towers; the bottom floors just looked like Alnwick while the upper floors took their stylistic cues from the original castle’s other conical turrets. Evidently Mr. Craig didn’t like the vertical extensions, because they were totally redone for the second film in a style that slightly foreshadowed the more Gothic look that would take over in the third film. (Interestingly, some COS shots still feature the SS version.) That revision stuck around till Half-Blood Prince, when it was replaced with a single tower echoing the bell towers’ design.

Since I’m working on the Azkaban castle right now, it’s that second iteration of the tower that I’m focusing on. And “focus” is indeed the right word, because I’ve spent a lot of time just staring at reference images and…thinking. Trying to piece it all together. Eventually, I started working on the facade toward the right:

This is the project’s first render with the OptiX denoiser, which wasn’t compatible with my GPU till Blender 2.90. Denoising is critical with path tracers like the Cycles render engine, where speeding up the render introduces more noise. I was using Open Image Denoise before, but OptiX is faster and it’s retaining more detail, so I’m pretty stoked!

Anyway, training grounds tower. It’s proving as challenging as I feared/hoped it would be. The modeling itself is not particularly difficult, but the paucity of high-quality reference images makes it difficult to piece together all the details, especially since I want to get the scale right.

I’m keeping an eye on the original version too, since the lower section is identical and I want to make sure I can reuse it without any issues.

In a twist that will shock precisely zero longtime readers, I’m finding lots of small discrepancies between shots of miniatures, location shoots at Alnwick Castle, CG long shots, etc. As usual, I’m striving for something of a happy medium, but weighted toward the main 1/24th-scale miniature.

There’s still a lot more to do on this structure, but it’s been 10 days since I last shared my progress and I think I’ll save further progress for my next post.

The Long Gallery & Starting the Bell Towers

Work on my 3D model of the Prisoner of Azkaban castle continues! The area that corresponds to Durham Cathedral’s north transept is now complete:

I shifted my way attention to the adjacent walls that correspond to the cathedral’s nave and north aisle, otherwise known at Hogwarts as the Long Gallery. I was surprised to notice that the windows and buttresses are not evenly spaced. In fact, the upper windows don’t even align with the lower windows. I fought this briefly, thinking I must be mistaken, but nope, I’m pretty positive none of this stuff lines up in the miniature – and not in ways that match the imperfections of Durham!

I wanted to match the miniature as closely as I could, so I started by adding placeholders for the bell towers at the other end of the Long Gallery to help me lock in my spacing:

The stand-ins are shorter than the talent, and their faces are kinda blank, but hey, what are you gonna do.

At this point I discovered that my entire Long Gallery area was about a foot too far east, so I took a few minutes to shift it over and swivel the viaduct accordingly (a whopping 0.25°). A foot’s not a lot – at 1:24 scale, that comes out to half an inch in the miniature – but it helps to line things up as closely as I can.

With that done, I blocked in the walls and roofs of the long gallery:

Then came the details, with all their subtly variable spacing. Here’s an orthographic view from the side – a perspective-less elevation view, in other words. All the misalignment is totally intentional, and it should be pretty accurate (although I made further tweaks after this render).

Of course, it’ll look better once the far side is enclosed as well; I’m not working on that courtyard side yet.

In the meantime, my next task was to create the 15-foot-wide octagonal tower on the roof of the Long Gallery. This was added in Chamber of Secrets; my guess is that it was a purely aesthetic decision, perhaps motivated by the fact that the establishing shot of the greenhouses shows that area more clearly than we had seen in the first film.

Pretty quick add, and it never changed in any of the later films. Just gotta make sure I exclude it from the eventual Sorcerer’s Stone version of the model!

Next up? The bell towers! While the central tower isn’t very similar to the one at Durham Cathedral, the bell towers have a lot more in common with their Durham counterparts, the North and South Galilee Towers. In fact, the basic impression of the original design in the first two films is that they’ve simply knocked a few of the pinnacles off and added a conical roof to each tower. (Closer inspection does reveal some subtle differences in the details, as with all the Durham areas.) In Prisoner of Azkaban, the conical roofs were replaced with taller belfries and octagonal spires that echo the redesigned central tower, but the lower sections still bear a striking resemblance to Durham Cathedral. They also get a lot more intricate than the central tower, which makes them a little intimidating. I decided to start with the bottom portion, which is all based off stuff I’ve already made:

Now for the hard stuff! Okay, it’s not exactly hard…it’s just…a lot.

Halfway there:

The openings are tricky. In some shots in the early films, you can very unambiguously see straight through from one side to another, but in some photos of the miniature from the Warner Bros. Studio Tour, it looks like there are interior walls. After finding other photos that seem to show straight through in the Studio Tour as well, I decided to keep mine hollow, as you see above. Hopefully that’s still accurate to the later films.

Next time we’ll finish the bell towers, add the wall between them, and continue around this northern part of the castle!

(Abandoned?) Side Project: The Literary Hogwarts

Thus far, this project has focused entirely on the versions of Hogwarts seen in the films (and theme parks). But I’ve been re-reading the entire book series as well, taking notes anytime some aspect of the castle or its environs is described – after all, if you pay attention, you’ll notice that it’s a completely different castle. For a long while I had this idea that it would be cool to create a model, illustrations, and/or floor plans for the book version of Hogwarts, but I wanted to make sure I had all the information first. In the meantime, I messed around with possible overall looks in 2D, though I didn’t arrive at anything I particularly liked:

Then I finished my notes on Deathly Hallows and compiled them according to different areas of the castle and grounds. I wrote out the following guiding principles for myself:

  • The goal is to depict in 2D and/or 3D what Hogwarts and its surroundings look like in my head, factoring in all the details given in the books.
  • Where details conflict between books, priority is generally given to descriptions that occur later in the series and/or more often.
  • The word “castle” is used to describe Hogwarts, but it’s evident from the descriptions that its features don’t always line up with what one would find in a real Scottish castle from the time period. At the same time, there’s nothing to hint at the Gothic cathedral architecture we see in the films. Here, we assume that this is a thousand-year-old boarding school built by magical people, sharing a lot of architectural similarities with contemporary Muggle castles.
  • We know the layout of Hogwarts is not 100% fixed; its magical properties do cause it to behave in some unusual ways. That being said, its overall layout doesn’t seem to change, based on the details given and on the fact that students can find their way around without a map. The approach here generally assumes a fixed layout with no fudging of the available space.
  • J. K. Rowling’s two hand-drawn maps of the book layout are taken as a general guide. Where details in the maps conflict with those in the books, the latter take priority.
  • The language in the books is not always particularly precise, so there is a little room for flexibility in the interpretation.

The process I had in mind was to start with the interiors, exploring spatial relationships between the castle’s various rooms, corridors, staircases, and so on. I figured if I could figure out how Dumbledore’s office relates to Gryffindor Tower, and how Gryffindor Tower relates to the Room of Requirement, and how the Room of Requirement relates the marble staircase, etc., etc., eventually I’d have a good idea of how to bring it all together.

With this in mind, I started my first layout experiments with the ground floor, since the entrance hall, Great Hall, and marble staircase are among the most frequently (and consistently) described areas of the castle. I took a bubble diagram approach and allowed myself to get really, really messy:

The areas closest to the entrance hall and Great Hall (GH on the right) were already feeling fairly locked in, but as you move further and further away, things get less and less certain.

Moving from the castle’s ground floor to its highest peaks, I started playing around with tower size and placement, since these will greatly impact the overall look and layout of the castle. I experimented in both 2D and 3D, again allowing for extreme roughness:

The existence of a bell tower is speculative; it’s never referred to as a tower in the book, but the bell seems to boom from somewhere above, perhaps especially close to the courtyard and classroom eleven. Considering how Hogwarts is a “vast” “towering mass” of “many turrets and towers”, I don’t think I necessarily have to limit myself just to the six towers that are explicitly described.

I next looked at the seventh floor. Here’s our first (and biggest) instance of the books not agreeing with each other. In the first three books, the corridor with the portrait hole to Gryffindor Tower seems to be on the third floor, but starting in Goblet of Fire, it’s very clearly on the seventh. Here I cleaved to my guiding principles above and accepted the seventh floor as canon. My other main landmarks on this floor were the Room of Requirement (RoR) and Dumbledore’s office, so I tried to work out how they relate to each other.

This is where I started getting a little overwhelmed with this side project and stopped working on it. I was also turned off by Rowling’s misguided comments about transgender people, which didn’t help. So for now, this side project has gone dormant, possibly to be revived someday…possibly not. In the meantime, I hope you enjoy this glimpse of my process. If you’re really interested in this idea, there are some other great attempts online. I’m thinking in particular of this one and this one.

The Boathouse Steps Aren’t THAT Stupid

Okay, after some massaging, I’ve gotten the photogrammetry meshes to line up a little better. This is always tricky because:

  1. The photogrammetry isn’t precise down to the millimeter – depending on the source images, the model can end up a little skewed.
  2. The technical drawings aren’t super precise either – for most areas, I don’t have detail drawings, only the overall floor plan.
  3. When lining up one photogrammetry mesh with another, you might need to adjust any or all of the following:
    • overall scale
    • x translation
    • y translation
    • z translation
    • x rotation
    • y rotation
    • z rotation

So, bottom line…these things aren’t as precise as one could wish, and you have to decide which which sources to trust, and that can vary from area to area.

Anyway, the adjusted photogrammetry confirms that different flights of the Half-Blood Prince boathouse steps (which are the same as in the previous two films) do indeed have different slopes, which is why my vertical dimensions weren’t working very well. In fact, to get everything to fit, I had to give almost every flight a slightly different slope. This seems awfully messy, but it also provides the best fit to the actual miniature.

That’s all being put on hold for now, though – I just discovered more reference photos that are helping me fill in areas that were otherwise difficult to reconstruct. In particular, I finally know what the original “link building” looks like! (That’s the small connection between the Great Hall/Chamber of Reception structure and the marble staircase tower; it changed to a different design after Azkaban.) So while I don’t have any renders to share for this post, I think the next one will cover the link building and the front of the quad building!

P.S. For the record, the boathouse steps themselves are actually a great design, beautifully executed in all three incarnations. I just get frustrated when I can’t get my sources of info to agree with each other, haha.