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:

The photogrammetry isn’t precise down to the millimeter – depending on the source images, the model can end up a little skewed.
The technical drawings aren’t super precise either – for most areas, I don’t have detail drawings, only the overall floor plan.
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.

The Boathouse Steps Are Stupid

Ugh. I’ve indeed proceeded to the boathouse steps, and it turns out that they’re evil.

It all started out innocently enough. There are super detailed drawings available for the Deathly Hallows version, so I started there. I figured I’d work backward to the GOF/OOTP/HBP version, and then finally to the SS/COS/POA version. Above is the DH version in the process of being built, along with a newly wavy lake surface. Below is what they looked like when I was done:

Okay, so far, so good. It looks weird, but that’s just because they’re untextured, they don’t have any walls, and they don’t match up with the POA castle around it. The technical drawings were very explicit and internally consistent, so I felt very confident in this setup. Next up: the version from the middle three films! Should be easy, right? Just follow the floor plans, and then adjust the height to match the exact vertical distance between the boathouse floor and the viaduct courtyard floor, right?

Wrong.

It all went askew when I compared my steps to this angle of the HBP model at Warner Bros*:

See how the steps come right up to the bottom of the boathouse roof? Yeah…mine didn’t do that. They stopped noticeably lower. Something was off with the vertical scale. Presumably, some of the flights were supposed to be steeper than others. But it also occurred to me that my vertical measurements for the boathouse weren’t particularly precise either, so it was risky to try to get these disparate approximations to match up with each other.

No problem! Fortunately, this version of the castle has better photographic documentation than any other, since it’s open to the camera-wielding public. I was particularly enthused when I found this video – I knew Meshroom would like the camera motion, coverage, and image quality. So I fed a bunch of frames into the photogrammetry software and let it run. Actually, I let it run multiple times on different subsets of images – running everything all together resulted in some errors. Then I plopped all the different scans together into the same physical space:

Not exactly pretty, because this is a half-dozen scans with different lighting poking through each other haphazardly due to the limited precision of this method – plus lots of junk data floating around. (A lot of the stuff up top is the lighting fixtures from the Warner Bros. Studio Tour, haha.) Still, I figured this should provide some good reference, right?

Well…it turns out that the floor plans don’t quite match up with any of the scans. So that’s annoying. Again, it’s probably the result of the limited precision of this photogrammetry, but it makes it tough to trust this information.

And that’s really where I’m at right now…still trying to figure out the boathouse steps. I may end up needing to adjust the boathouse’s vertical scale, too. Oy…wish me luck.

* Apologies to the photographer for not giving credit. I’ve somehow lost wherever I found that image. If you recognize it as yours, please don’t hesitate to let me know!

Great Hall Balconies, Pepperpot, & Pre-DH Boathouse

Work continues on the Prisoner of Azkaban iteration of Hogwarts! I guess my return to the project might have legs.

(Forgive the exposed interior glow panels on the right again.)

With the Chamber of Reception complete, I moved on to the terraces or balconies surrounding the Great Hall, plus the foundations below. Good lord, the geometry of these corbels gave me a headache as I tried to reconcile a variety of imprecise measurements and calculations. I’m pretty happy with how they turned out, though. And I sure was thrilled when the spacings of the corbels and the torches lined up! I added the finishing touches to the pepperpot as well.

This also afforded the opportunity to check out some angles not seen in the films, such as this nighttime view looking toward the head of the Great Hall from the balcony outside:

Soon I was faced once again with that perennial question: what next? At first I considered doing the crenelations outside the Chamber of Reception and the steps down to the boathouse, but as I assembled reference images, I found myself drawn to the boathouse itself.

It’s a simple structure with a lot of good reference out there, since it never changed till the digital rebuild of the castle for Deathly Hallows (when it was completely redesigned), and visitors to the Warner Bros. Studio Tour can get quite close to that part of the model. As a result, it came together pretty quickly. Here it is in complete form:

I really like that last one. I wanted the boathouse to “pop” in front of the similarly-colored castle behind it, so I went with a shallow depth of field and ended up with this render that kinda looks like a miniature itself. You can even see the witch-and-black-cat weather vane at the top. And, as I mentioned last time, I finally got a decent stone floor texture going, though I’ll probably still tweak that some more.

Next up…the boathouse steps, I suppose? Speaking of which, it just occurred to me that the first-years have to climb the height of a 14-story building to get from the boathouse to the Great Hall for their Sorting. Between that and the nerves, it’s amazing they all manage to stay on their feet.

Chamber of Reception

For the first three Potter films, a large antechamber or entrance hall sat in front of the Great Hall. Its interior – the very first interior of Hogwarts seen on film – was shot on location at Christ Church Cathedral’s Great Staircase at Oxford. Stuart Craig and his team didn’t attempt to recreate the exterior of this structure in the visual effects miniature of Hogwarts, but the design they came up with does draw some details from that real-world location. Although this room is never explicitly named in the film, Harry’s prop acceptance letter instructs him to report to the “Chamber of Reception”, and the name (seen only briefly onscreen) seems to have stuck with the fan communities. The closest equivalent in the books is the entrance hall.

For Goblet of Fire, Hogwarts received a new courtyard and tower in front of the Great Hall, and the Chamber of Reception went the way of the dodo, never to return. In its place was an entrance hall with a smaller footprint and very different appearance. It’s a great look, but I’m very fond of the Chamber of Reception, due to my particular nostalgia for the first film. Fortunately, since I’m working on the Azkaban version of the castle, I get to include it in my model!

Getting the vertical dimensions of the Chamber of Reception required some use of photogrammetry and inference from known elevations of adjacent areas. Soon, I had a basic shape roughed in:

That chimney that protrudes from the corner on the right is a detail taken from the real thing at Oxford, by the way. Thanks, Google Maps:

The miniature also incorporates the exterior steps and the light fixture above the arch, even though there are no location shots of those in the film, leading me to believe that they at least considered shooting some stuff just outside this building at Oxford.

Anyway, I kept the same camera angle for the renders that followed. I began to block in the so-called pepperpot building on the left and added more details to Chamber of Reception:

The last round of details really brought it all together, completing the Chamber of Reception (other than some windows I may add to the far side). The tracery on the windows was tough, since reference for those is quite limited. I think what I came up with is pretty decent, even if it’s not 100% accurate. I also had to refer to the hammerbeam roof interior miniature from the first film for the rose window on the front of the Great Hall – I can’t find any closeup shots of the exterior, but there’s a corresponding rose window in the interior miniature.

I even included that real-world lamp above the arch, plus another Hogwarts-style sconce next it that’s visible on the effects miniature. They’re hard to see in the daylight, so…Nox!

There’s still more to be done here with the interior lighting, but I do like the way this is turning out. You’re actually seeing into the lit interior of the Chamber of Reception and Great Hall; most of the other windows in my model just have flat panels behind them that give off a splotchy orange glow for night shots, a cheat that’s very obvious in the exposed interiors seen to the right side of this render. But the Great Hall and Chamber of Reception have large windows into large spaces with known interior architecture, so I didn’t want to fake it with these.

I think I next need to add details to the pepperpot, and then either the link building or the terraces around the Great Hall. We’ll see what order I end up springing for. I’m also going to need to create a new texture for the paved horizontal surfaces like those terraces – so far I haven’t done anything like that.

We’re Back! …at Least for Now!

Well, it only took a pandemic to get me back into this project! After the better part of a year working on other stuff, I’ve reopened my Hogwarts 3D model and begun adding onto it again. I still have some other big projects I’m working on, so I don’t know how much further I’ll get or at what speed, but it’s nice to at least have an update!

The first order of business was to finish up the main window of the Great Hall. The exterior version of it, that is – in interior scenes, the top of the window has a pointed arch shape, whereas the miniatures (and, for Deathly Hallows, computer models) used for exterior shots had a rectangular shape. Here’s a render of the end product, using a familiar camera angle from last year:

Felt good to have that finally finished! Next I began the central spire above the Great Hall, as well as the dormer windows along the roof. That spire is notable because of how steep it is. The castle originally had a lot of short spires, most of which became much steeper in POA, but this one was steep like this from the beginning:

Just like olden times, I got to wrestle with different references (film frames, production photos, photos of the model from the Warner Bros. exhibit, technical drawings, photogrammetry from the films, etc.) and try to reconcile them all into consistent dimensions. This can be surprisingly difficult at times, although it got easier when I remembered that the Great Hall got widened after POA – that explained some of the biggest discrepancies.

With the addition of more detail, the Great Hall itself is now finished, more or less:

I say “more or less” because the other side of the Great Hall is where it interfaces with the chamber of reception/entrance hall, depending on your preferred verbiage. That side is currently a featureless wall:

The next steps will be to start adding the entrance hall, which will cover most of that blank wall. Then we can add some of the terraces around these structures and the small building that connects the Great Hall to the marble staircase tower next to it. More to come, I hope!

On a more serious note, if you’re reading this during the COVID-19 pandemic, I hope you and your loved ones are safe and well-isolated, as dictated by the severity of the situation in your area. These are crazy times and (he reminded himself) it is more important than ever to be forgiving and patient with each other – and ourselves. Sending lots of love!

Also Introducing…My 3D Star Wars Blog!

If you’ve been enjoying this blog so far, you might want to follow this new one I’ve started as well. Even as I track the changes to the design of Hogwarts, I’m also recreating the sets of the original Star Wars trilogy, including their real-world location within Elstree Studios.

If you’re not a Star Wars fan, don’t worry – the Hogwarts project isn’t dead. As promised, I’ve moved on to the Great Hall exterior. More on that coming soon, I hope. In the meantime, here’s a teaser…

Marble Staircase Tower, AKA Dumbledore’s Tower, AKA Turris Magnus

All right…as promised, it’s time for one of Hogwarts’ most recognizable exterior design features to go from simple block-in to fully detailed model. I’m talking, of course, about the marble staircase tower, also referred to as the turris magnus (on the Marauder’s Map) or Dumbledore’s tower. You can go all the way back to Stuart Craig’s original concept sketch for the Hogwarts exterior, and this tower is already there. It’s the biggest tower, the one on the left. A few of the details are slightly different than the final design, but it’s pretty close:

This thing is massive. To give you a sense of scale, in the real-world environment envisioned by the design team, the top is over 600 feet above lake level. The main body of the tower is 92 feet wide. The spire alone is over 200 feet tall, with somewhere around 50 feet of that being the enormous copper finial at the top. For my fellow Disneyland fans…the entire freakin’ Matterhorn would fit inside the spire. Near the top, that smaller triple turret on the left is Dumbledore’s office; the castle’s moving staircases sit below, inside the cylindrical body of the tower. Mr. Craig has readily acknowledged in interviews that there are design choices here that simply couldn’t be built in real life. Fortunately, magic covers many architectural sins, and personally, I think the films are all the better for it. The turris magnus is featured prominently in the very first shots of Hogwarts and it’s part of what made such an impression on me in the early 2000s.

The first detail I wanted to capture was the dormers sitting along the sides of the spire. This is where the ridiculous, over-the-top dragon chase in Goblet of Fire really came in handy, because Harry and the Hungarian Horntail end up on these rooftops, providing closeup miniature shots and even closer shots of a partial set for Daniel Radcliffe to interact with. I decided to incorporate all these details into the dormers, even though the main 1:24 scale miniature probably wasn’t quite this detailed. (The closeup shots were accomplished with other bespoke miniatures on larger scales.)

Let’s also pull back for a wider shot, including some detail work on the finial and the beginnings of work on Dumbledore’s office:

(By the way, sorry for that other spire near the bottom middle, the one that has the copper patina discoloration near the top but no finial. Keeps showing up in renders. Eventually I’ll add the finial, I promise!)

Next came the stepped corbelling at the base of the turrets of Dumbledore’s office, and their own much smaller spires began to take shape as well. This was all slightly complicated by the fact that what few technical drawings I could find were not quite accurate, but I think I got pretty close in the end.

Here’s where I ran into a conundrum, though. As I mentioned, the closeup shots in GOF were accomplished with larger miniatures built just for those shots. As I looked more closely, I realized that the design of these turrets is a little different in these miniatures than in the main miniature – mainly in the design and placement of the windows. I couldn’t decide at first whether to go with the more detailed alternate design seen in GOF (and the theme park versions) or just go off of the main 1:24 model. The former was tempting at first, since the changes were clearly done to help the exterior match the interior sets designed for Chamber of Secrets. Speaking of which, as massive as this whole tower is, Dumbledore’s office is actually still smaller than the actual set. I thought that was pretty interesting. Below is a very simplified version of the interior set (in white) next to the exterior, using the real-world scale of the set and the intended imaginary scale of the exterior. (The vertical protrusions on the right are where the windows are; they didn’t build the sets with full-thickness walls, so they look like they’re sticking out.)

Anyway, the main model’s design won out in the end, and you can see the corresponding simple window designs have been added here. I’m technically still working on the POA version, and the redesigned exterior wasn’t created till GOF; when I get to GOF, I’m sure I’ll build the redesigned version too.

That makes the spire more or less complete, although I may go back in and add in details like roof flashing where Dumbledore’s turrets meet the main spire. For now, I moved on to the main body of the tower, adding corbels and windows:

From there, it was just a matter of building the larger windows that cover the rest of the tower below! In studying my 16,000-pixel-tall collage of reference images for this tower, I noticed that the spire has actually been mounted on the tower at a variety of angles over time, and there were again some discrepancies between the actual model and the technical drawings. This made it harder to figure out the radial spacing of the windows, but in the end, I did some measurements on my old photogrammetry of the castle and settled on there being 18 windows on each floor. Hopefully that’s correct, haha. In any case, here’s the complete tower!

As I continue around this corner of the castle, we’ll next be proceeding to the only other feature that’s as visually important as the marble staircase tower: the Great Hall!

Night Falls on Hogwarts

I liked that fire material from the last post so much that I kept finding myself virtually lighting the torches and switching to that day-for-night setup. Eventually, I got wise and decided to create a dedicated “night mode” for the model. It has a different HDRI for the background (a cloudy daytime scene from HDRIhaven.com that I made much darker and bluer), stylized blue lighting to match the moonlit shots in the first couple films, and interior lights behind some of the windows. Compare:

Best of all, I realized I could use Blender’s node group functionality to create a single slider that would allow me to change all the different settings between day and night simultaneously. I also did the same for the two color modes (the warmer look of the first two films, and the desaturated look of the later films, seen above).

Both tasks were made easier by some behind-the-scenes organizing I’d been doing. The procedural (algorithmic) brick texture on all the walls had gotten really complicated, because I was layering so many different elements together in the pursuit of a realistic and visually pleasing result. For kicks, I thought I’d share what the brick material’s node tree looked like before:

Each of those little gray boxes (nodes) is a set of calculations, receiving inputs and sending outputs via those light gray lines that connect them to other nodes. I’d organized them into those colorful groups, each of which has a descriptive label, but it was still a pretty ugly setup and not that easy to use or “read.” Here’s the same material after visually organizing the node tree a little better:

Not only does this look cooler, but it’s a lot easier for me to just jump in and make changes or additions where needed. (Which I’ve already done repeatedly since taking that screenshot…the setup is even more complicated now, but still nicely organized.)

You might have noticed that long wall at the bottom right of day/night renders, connected to a small tower. These new additions will barely be seen in the final version of the POA model – they were part of the original model from the first film, but starting in Azkaban, the landscape became much hillier and it literally swallowed up most of the wall and the entirety of that tower. But I decided to build the whole thing now so that it would be easier to create the versions for the first two films when the time comes. Here’s another shot:

There’s also some work happening here on that wall beneath the hospital wing bridge, just to the right of Gryffindor Tower in this image. Here, let’s take a closer look with the clock tower and hospital wing temporarily hidden, and some improved texturing on the roofs and spires:

Windows, dormers, drainpipes, corbels, the whole nine yards. That wall is done now, and you can even see some work happening on the tower on the right. Fast-forward a bit, and here’s a closeup of that tower, now complete as well:

Some of this geometry was definitely tricky to get right, but it was worth it in the end. I also had a lot of fun with the decorative elements near the top – there’s a triquetra near the top of each dormer, plus some sort of decorative plaque just below. I couldn’t quite figure out what is embossed in the plaque, so I just sculpted something that looked similar and baked it as a normal map. [EDIT 4/24/19: I finally found a clear enough photo of the plaque – it’s the Hufflepuff crest! Guess I’ll have to go in and redo it at some point…] You can also see the new diamond-shaped muntins in the windows, which are now in all the windows of the castle so far. (I admit that I didn’t go procedural with these…I briefly tried, but it just seemed more efficient to use a single diamond image that I could tile all over the glass.)

Taking a closer look, though, the roof shingles aren’t supposed to get flattened out in some places like that. Always more to be done!

More POA Hogwarts Texturing

Well, so much for turning the materials off and focusing on the modeling again! The process of creating and tweaking and refining these textures has become a bit addictive.

Here I’ve created a shingle texture for the roofs and spires. The finials have also received a copper patina treatment to match what we see in the films. (Again, no image textures here – all procedural.) Less obvious are some subtle adjustments to the brick texture. Notice how the bricks no longer appear to be all perfectly flush with each other – some stick out slightly further, like you’d see in real medieval construction. There were still more tweaks needed, though. In particular, I wanted more vertical streaks to mimic dirt deposits from years of rain and weather. Those are quite noticeable on the “real thing.” Many hours later…

…that’s more like it! Still not perfect, but I don’t think I’ll be able to convince current versions of Blender to do any more on their own. I could paint the streaks in myself, but I’m still really trying to stay procedural so that when I build the rest of the castle, the brickwork and weathering and dirt patterns will all just magically appear without any further work. (Unrelated, but you can also see a few contour lines down near the shoreline. Once these are completed, they’ll act as a guide for me to sculpt the landscape the castle sits on.)

If it’s been a while since you’ve seen the first couple of Harry Potter films, you might be thinking that this castle looks awful colorful. Were the bricks really that red, the roofs really that bluish? Well…yes, at first. The Hogwarts we see in Sorcerer’s Stone and Chamber of Secrets has pretty saturated colors. Here’s a frame from the latter, for instance:

It was really only once we got to Prisoner of Azkaban that the colors took a turn for the grayish green. At least part of it was just color grading on the film; it’s hard to tell if the miniature itself received a cooler paint job, but if it did, it wasn’t as dramatic a difference as it appears in the film:

That’s more or less the color scheme we see through the rest of the series, and the theme park versions at the various Universal resorts don’t stray far from this look. So despite my original intention to just get the original look of the model, I created an alternate coloration for the model, too:

It’s still not as green as what we often see after the first couple films, but it’s at least closer. I set up the material nodes in Blender so I can quickly switch between color schemes across the whole model; I suppose I’ll probably stick with this coloration while I continue work on the POA version, but the more colorful version will be ready to go when I start working on the castles of the first two films.

I’ll round out this post with kind of a cool, different shot of the castle in silhouette. You can see I’ve finished the windows on the Defense Against the Dark Arts tower, although I discovered a small mistake in the lowest row of windows after this render was made. Unfortunately, this angle also highlights some of the areas where the bricks don’t map quite right onto the forms of the castle. After a lot of experimenting, I’m starting to think this may be as good as the mapping is going to get. But who knows?

The Defense Against the Dark (3D) Arts Tower – Plus the Textures of Hogwarts

Work continues on the Prisoner of Azkaban version of the castle. My tentative plan at this point is to more or less finish this iteration before fully jumping to any of the other films…but I’ve been known to jump around, so who knows.

The latest structure to take shape is one that other Potter fans seem to refer to as the Defense Against the Dark Arts tower. Apparently the video games place the DADA classroom in this tower, so the community rolled with it. Anyway, this was first seen in Sorcerer’s Stone, and it stuck around through Order of the Phoenix,with a slight relocation from Azkaban onward. (After that, it was replaced by the Astronomy tower, which is basically just a taller and more extravagant repurposing/redesign of the DADA tower.)

There he is, just to the left of the Dark Tower. Basic shape starting to form.

As I continued to work on the top part of the tower, I realized that the DADA->Astronomy transformation (transfiguration?) actually “revealed” some parts of the DADA tower that weren’t visible before. Presumably, these were designed specifically for Astronomy, but I figured it’d be more efficient for me to just create them from the start and conceal them with the remaining DADA structures; then they’ll be ready to go when it comes time to do Half-Blood Prince. Below you can see the Astronomy-ish version on the left, and then on the right we see one of the turrets that conceal some of the geometry on the DADA version.

Then I started adding a few more details on the top part of the tower, resulting in the following render:

…which I liked, but I was starting to get fed up with my plain blue placeholder for the lake surface below. I knew I didn’t want to spend time creating (and rendering) full-on water shaders, but I thought it would at least be cool to try to create some atmospheric perspective (mist) along the horizon. In the process of working that out, I started running into some ways to break up the surface of the water a bit, too, and I couldn’t help myself. Soon enough…

That felt like a good step in the right direction, but it wasn’t enough. I kept going and eventually ended up with this shot, which I gotta admit, I really like.

The reflective water shader has some procedural variation in the roughness to simulate areas with more or less wind. There aren’t any actual waves, though…if I ever decide I need to get in close, it’ll need more work. Then there’s some volumetric fog along the horizon. (It’s literally just a huge torus with some cloudy volumetric shaders on it; I distorted it and put it way out in the distance to help blend the edges of the water with the HDRI background.) I love how my fog blends right in with the photographic clouds just above, particularly from this angle.

Now I was in full-on texturing mode. If I were a wiser man, I’d save all this for after I finish modeling…but where’s the fun in that? I decided I wanted to start experimenting with textures for the castle itself, too. And I decided I wanted to go all procedural.

I mentioned that word before, “procedural.” I’m inevitably going to use more CGI lingo in these posts than I have time to explain for those of you who don’t do 3D art, but this one is worth delving into for just a sec. Basically, anytime you apply a texture to a computer-generated object, the two most common ways to do it are to apply images to the surface or to work procedurally. A procedural texture is one that doesn’t involve any images – instead, you’re telling the computer how to mathematically generate the imagery based on the surfaces it encounters. There are many pros and cons to each, and they each have a lot of uses. One of the pros to going procedural is that if you set it up right, it’ll conform to stuff you build in the future, too. And of course, I still have a lot to build.

Anyway, bottom line, I’m trying to completely avoid using pixel-based images in this main castle texture. After fiddling with dozens of nodes, I came up with this:

We’re starting to get there. It’s beginning to have that stony, bricky, castley look. These color patterns were starting to work for me, but the nodes weren’t behaving quite the way I expected with regards to the way light reflects off the surface (specular, roughness, and normals). I found the problem, did more tweaking, and arrived at this improved version:

The difference is fairly subtle, but to my eye, this looks a lot more realistic and lot more accurate to the films. (Of course, getting a single texture that fits the look of all the films would be impossible, since the color grading changed so much after the first couple of films, making everything kind of greenish-gray. I’m trying to just match the physical miniature as best I can.)

Still, this is very much a work in progress, and it probably won’t be too long before I turn the textures off and just focus on modeling some more.