Fixed Vertical Scale, POA Training Ground Entrance, & Hogwarts Torch Sconces

Okay, I might have overreacted a little bit. The vertical scale issue didn’t take that much work to remedy; I forgot how relatively little I’ve modeled so far. A 5% increase in height got everything back on track, although I had to be careful with a few shapes that needed to stay perfectly circular or perfectly square. Here’s how the results look:

…yeah, pretty much the same as before. Hey, it’s only 5%. But this small fix will help ensure that all the different structures line up correctly as I continue to build.

Hippogriff-eyed viewers might notice the addition of the so-called training grounds entrance, just to the right of the DADA tower. I say “so-called” because it stopped being an actual entrance after Chamber of Secrets. Originally, this small cubical building connected to the suspension bridge on one side and the training grounds on the other. But then the suspension bridge moved in Azkaban, turning this building into a dead end that could only be accessed from inside the training grounds. It never changed back. Still, this seems to be the name that the fan communities are using, so I’ll roll with it. (Except for in the internal layer organization of the model, where I stubbornly refer to it as “small cubical building.”)

While you’re taking a peek at this modest addition to the model, you might also notice the torches burning on either side of the archway. I’d been meaning to model the black wrought iron sconces seen in numerous exterior shots, and this was the perfect chance. As always, I started without texturing:

As I worked on this, I noticed that the bowl of the sconce was always empty in daytime shots, but always full of visible firewood (?) when the fires are lit at night. I’m taking a similar approach. Here’s a classic day-for-night shot of the torch by Sirius’s cell atop the dark tower, created by significantly reducing the brightness of the daytime background HDRI:

I’m rather proud of the simple little fire material I created, too. It’s a volumetric shader applied to a roughly conical shape, with black firewood shapes down in the base. The 3D texture that simulates the characteristic shapes of the flames is tied to the world coordinates, not the local coordinates of the individual fire object, which means I can duplicate the exact same torch and fire objects but still get a unique pattern of flames on each one – very important in areas where multiple torches are in close proximity. Then, when switching back to daytime renders, all I have to do is rewire a couple of nodes to hide all the firewood and flames across the entire model.

The one thing I didn’t like about this render was that some areas of the stone bricks are just too smooth, though. So I went back in and beefed up the normal maps that simulate the rough, bumpy surface texture. If you look closely, you can see a bit of it in this last render of the training grounds entrance, though I’ll probably keep tweaking it as I continue. (Also, I forgot to un-hide the lake surface below for this render, so you’re just seeing the photographic bottom of the HDRI background. Whoops.)

One last thing I keep forgetting to mention: If some of these buildings in this model look like they start too low or are too tall, that’s just because the surrounding terrain will cover most of the base areas. Because the terrain is so uneven, there are lower areas that get exposed here and there, and my model already includes those lower areas. Once I’ve got the ground and the hills and the ravines in there, it’ll look a lot more…Hogwartsy.

Measure Twice, Build Hogwarts Once

Crap.

One of the first things I do on a project like this is set up all my technical drawings and references to scale in 3D space. No sense in starting a model if the different elements aren’t even to the same scale. So when I started this project, sure enough, I was careful to set up all my reference images to scale.

Or so I thought. I just discovered an issue with the vertical scale: it’s around 3-4% too short. I don’t think the issue extends to the horizontal dimensions; I just need to stretch some of the elevations vertically. (The elevations in question are Prisoner of Azkaban drawings; I’m using perspective-corrected photos of blueprints at the Warner Bros. Studio Tour in London, so there was always the potential for the vertical scale to be wrong, but I thought I’d already fixed that.)

I know that a few pieces of very useful height data can be found in a drawing in Harry Potter: Page to Screen, which I really should have picked up a long time ago anyway, so I’m off to Barnes & Noble later today. Then I can start the arduous process of figuring out which elements of the model need to be fixed…

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.

Complete in 3D: Gryffindor Tower (POA Version) and the Dark Tower!

The rest of the work on the Prisoner of Azkaban version of Gryffindor Tower proved pretty easy. The remaining windows came together quickly.

I even added this mysterious pipe-like thing that juts out directly over Harry’s window (near the top middle of this render). No idea what it is…it’s been there at least since Goblet of Fire, probably since Azkaban or earlier, and it’s still visible to this day in the main VFX miniature at the Warner Bros. Studio Tour in London. If you happen to have any idea what it is, be sure to leave a comment!

You also can see I removed the suspension bridge at the lower left. It’s not completely deleted, just moved to a hidden layer; it needed some reworking that I just don’t want to deal with at the moment. It’ll come back eventually.

Work then moved on to the Dark Tower. Whereas Gryffindor Tower was just revised a bit for the third film (mainly making it taller), the Dark Tower was an entirely new addition. Its purpose was to provide a visually dramatic location for Sirius Black’s cell at the end of the film. It sits roughly where the real-world Durham Cathedral chapter house structure sat in the first two films.

The basic structure of the tower is super simple – just a slightly tapered cylinder with an off-center pyramidal base. Sirius’s cell is perched right on top; the render above shows the front wall of the cell beginning to take shape. I kept going and eventually finished all the detail on the top of the tower.

The most interesting challenge ended up being those four stone gargoyles near the top of the tower. These are never seen up close in the films…they pretty much just look like vague oblong shapes with a skinnier protrusion at the end. But I started doing some digging in the various video games released around this time, and I found some much closer shots. To my surprise, the games reveal a design that looks more like a vulture than anything. Now, the games obviously use 3D assets built specifically for the games, and the design can totally change in the process of translation from film to game. But these closer shots seemed consistent with the blurry shapes visible in the films, so I decided to just go for it. They gave me some fun practice with sculpting and retopologizing.

The rest of the tower really doesn’t have much more detail on it, so I’m calling it finished! Here’s a render showing the completed tower with the rest of the model so far. ~~Fun fact – Harry’s window actually looks pretty much straight at the tower where his godfather ends up being briefly held. That’s kinda sweet.~~ Whoops, this isn’t true – the Defense Against the Dark Arts tower totally blocks the view of the Dark Tower from his window. Never mind!

I’m planning on starting what fans have been calling the Defense Against the Dark Arts tower next. See you soon!

3D Gryffindor Tower; or, Harry Potter and the Cursed Corbels

In the last week, I got fed up with some parts of the Prisoner of AzkabanHogwarts exterior near the suspension bridge that I really can’t find much information on. So I decided to switch gears and add more detail to Gryffindor Tower – in particular, I wanted to create the corbels that support the top part of the tower, where the boys’ dormitory is.

It turns out this is tougher than I expected, and it turns out explaining why is pretty tough as well. It has to do with the way the corbels shrink inward (or don’t) toward the center of the tower, and the way they extend all the way out to become part of the circular shape of the tower, and the way they have semicircular notches carved out between them. You can see a few examples of these designs in this shot from Sorcerer’s Stone, although Gryffindor Tower itself isn’t visible here.

This became quite a roadblock. Every time I thought I had it, Blender would spit out results that looked wildly wrong. So damn frustrating. So I did what any responsible adult would do: I threw up my hands and switched over to something completely different, a music project I’d been working on prior to the Hogwarts project.

As a result, I spent the last few days not thinking about polygons or Array modifiers or enchanted Scottish castles, and it turned out that this did a world of good…when a piece of missing hardware stalled my music project, I reluctantly decided to give the corbels another shot. And whaddaya know? I figured them out pretty quickly!

It took a mixture of Array and Screw modifiers on different objects combined with Boolean operations in a specific order. The results aren’t anything insanely spectacular to look at, but they’re decently accurate, and I should be able to use similar techniques elsewhere on the castle. (Ignore the vertical banding on the tower, by the way; you’ll sometimes see this in curved areas I haven’t yet bothered to smooth out.)

One interesting challenge with this tower is that some of the details actually change from shot to shot in a given film. The reason is simple: some of the visual effects shots in the films are actually composites of multiple miniatures on different scales. The main castle miniature was built at 1:24 scale, which is great from a distance. But for closeup shots, the team built larger versions of specific sections of the castle and composited them in with the main model. For instance, this VFX shot of Gryffindor Tower from Goblet of Fire is nicely broken down in a video at the Warner Bros. Studio Tour in London. The first image here shows a smaller model with part of the tower removed; the second image shows what it looks like when the larger, more detailed miniature of the tower is composited in, allowing for quite a close shot.

This wouldn’t pose any issues for my model, except that it turns out there are actual design differences between the different miniatures in some cases. For Gryffindor Tower, I was specifically noticing the cornice around the base of the conical roof. It has a decorative sort of double curve to it here, right? Well, compare it to the main miniature in this photo from the aforementioned Studio Tour:

The cornice is much simpler and flatter. I’ve spotted a few other spots that change like this. So that raises the question…which version do I create? So far, I’m mostly opting for the most detailed versions I can find; notice that my render above includes the more detailed version of the cornice. But I’ve got to admit, it feels weird to built something that doesn’t fit with the design of the main model. (That’s another reason the suspension bridge is tricky, incidentally…its design actually changes depending on whether we’re looking at the main model or a closeup.)

Anyway, I gotta go build some more castle windows. More updates soon!

3D Photogrammetry Scans of Universal’s Hogwarts

One of the ideas that struck me fairly early in this project is that it would be cool to compare the theme park versions of the castle to the “real” versions in the films. If you’ve ever walked through the Wizarding World of Harry Potter at Universal Studios in Orlando, Hollywood, or Japan, you know just how overwhelming it is to approach the towering facade of Hogwarts. Very effective theme park design.

Even so, much of the castle has been removed, the remaining sections have been modified, and the scale has been significantly reduced. (The filmmakers built their original Hogwarts miniature with a very specific real-world scale in mind.) The theme park version is highly evocative of the castle seen on the silver screen – specifically in Half-Blood Prince – but it’s still its own thing. (Three things, actually, since there are even slight differences between the versions at the three resorts.)

So…what would it look like to plop the Universal version down next to the cinematic version? That’s a question I intend to answer as the project progresses – hopefully with renders of them side by side! – but for now, you’re going to have to settle for these incomplete and very rough 3D scans of the Hollywood version.

These images are the fruit of photogrammetry, the science of extracting 3D measurements from photos. On a recent visit to Universal Studios Hollywood, I took about 400 photos of the castle. After heavily color-correcting these shots in Photoshop to bring out shadow detail, I threw them all into Meshroom, which dutifully set out to create a textured 3D model from the photos without any need for human assistance.

The first attempt failed. Unfortunate, but not surprising. There were angles I couldn’t capture due to the geography of the park and my own time constraints. (Not to mention the fact that we were trying to, you know, enjoy a day in the park!) Meshroom got confused and couldn’t connect all the disparate parts into one unified 3D model.

Not a problem. When I split the photos into six different sets that focused on smaller sections of the castle, Meshroom handled each set just fine on its own. Then I brought them together in Blender and manually lined them up with each other on top of an aerial photo. An HDRI sky added a bit of visual interest to the environment.

The scans needed a lot of manual cleanup, and even so, you can still see a lot of yucky fringes and artifacts, especially around the edges of each scan. That’s totally fine for my purposes…this is all just a rough guide for when I create my own model from scratch.

Still, interesting to look at, huh?

Hogwarts 4D Progress: “Azkaban” Suspension Bridge Takes Shape

One thing about me is that I don’t like to stick to any one part of a personal project for too long. So sure enough, I’ve put the Alnwick model on hold as I’ve jumped back to the Prisoner of Azkaban version of the castle.

At the moment I’m mainly focusing on an area of the castle that’s not very visible in the films. On a basic level, the castle (not counting any outbuildings, etc.) consists of two separate buildings that are attached by a few bridges over a deep, narrow ravine. The northern building is modeled largely after Durham Cathedral while the southern building includes the rather more unique designs of the Great Hall and Turris Magnus (the tall, steep tower with Dumbledore’s office near the top). It’s the southern building that I’m working on at the moment…but I’m focusing on the northern facade, the one that faces the other building. The filmmakers didn’t have many reasons to send their cameras through that area…but that doesn’t mean I can’t!

Obviously there aren’t any textures here, but this is another example of an area that’s approaching final levels of detail. The last few renders are especially cool to me because they’re from angles that would be impossible in the “real world” – the camera would be underground, or inside the northern block.

Some of my most proud moments since the last post have included sculpting a bas-relief Hogwarts crest (seen on the white square near the top of the last render above) and figuring out the Turris Magnus spire, whose shape smoothly blends from a hexadecagon (16 sides) to a circle near the base. I also like the suspension bridge, one of three footpaths between the two blocks of the castle. (Its biggest moment in the films is in Goblet of Fire, when the dragon chases Harry right through/past it…but that shot is over in, like, a second.)

Ooh, as an added bonus, here’s a fully navigable version of the model via Sketchfab. There are some numbered annotations that point out landmarks. I don’t plan on uploading one of these for every single future post, but I’ll try to do it from time to time so you can go exploring.

Have fun!

Hogwarts Gets HDRIs in Blender 2.8

I’ve been eagerly tracking the progress of Blender 2.8, the upcoming version of the free 3D software I’m using for this project. It’s still in beta, so it’s not recommended for use in production. There’s always that small chance that it will crash and eat all your data. And unfortunately, I don’t know any spells that will uncorrupt a .blend file.

Nevertheless, yesterday I made the switch! 2.8 has some truly incredible new features that will be really helpful for this project, and I just couldn’t resist any longer. It’s not worth getting into the technical side of things here, but suffice it to say that for me, this is an upgrade that’s worth the minor inconvenience of performing manual daily backups.

At the same time, I’ve been adding in some HDRIs. HDRI (high dynamic range imaging) refers to a particular type of environment for the model. It allows a lot of possibilities for dynamic, realistic images, and one of the easiest ways get started is to use HDRI photography made available online. (Thanks for the incredible freebies, HDRI Haven!) The results can be pretty cool:

Note that the castle isn’t actually sitting on those pretty mountains; those are just part of the photographic HDRI background that’s also providing lighting for the model. This angle just happens to make it kinda look like it’s sitting on the mountains. (My plan is to model the landscape around the castle later on.) Also note that this was rendered with Blender 2.8’s new EEVEE engine…it’s not nearly as accurate as Blender’s more robust path tracer, Cycles, but it’s insanely fast. The render above was done within 6 seconds. I can move around the model in real-time and it looks almost exactly like that.

You’ll see some blocky shapes in the back of that render, too. Those are just placeholders for some of the structures in the back of the castle; I’m trying to figure out height data by matching camera angles from the films. Compare these two shots:

Pretty close in terms of angle, right? (This was rendered prior to the switch to HDRIs in Blender 2.8, hence the plainer sky.)

Simultaneously, work continues on the separate Alnwick Castle model. On the right, the octagonal towers beginning to take shape, rendered with the slower but more accurate Cycles engine. (This is what Hagrid was dragging the Christmas tree toward in the first film.)

And here’s an EEVEE view from slightly later in the process. They’re a lot taller here than in real life, since Stuart Craig and his team basically took the footprint of this building and stretched it way higher. You’ll also note that I’ve loaded another HDRI sky into this model.

Still soooooooo much more to do…I’m really still just getting started. But the new features in 2.8 are going to be a big help! I’m also making slow but steady progress on a mega-post that will use stills from the films to illustrate some of the major design changes that this blog is all about. Stay tuned!

Getting Caught Up: The Hogwarts Project So Far

All right, let’s take a look at the project so far, since I’ve already been working on it for, like, a month before starting this blog.

First step was to gather as much information as possible: shots from the films, photos of the original Hogwarts miniature from the Warner Bros. Studio Tour, publicly available technical drawings of the miniature, behind-the-scenes footage, tourist photos and drone shots and floor plans of real-world filming locations…you name it.

Then came the important decision of where to start the 3D model – and which version to start with. Rather than jumping right in with super detailed final meshes, I blocked in a few basic shapes from the various films as a proof of concept in Blender. (My biggest concern was whether I had enough “vertical” information about the heights of various elements; I was pretty set on floor plans.)

Satisfied that this thing was actually going to work, I started over from scratch. The Prisoner of Azkaban version of the castle seemed like the best place to start.

Hey cool, it’s starting to look like Hogwarts!

Then something else occurred to me. I thought back to circa 2008, playing around with the now-defunct Photosynth service from Microsoft. You would feed it a series of photos of the same object or setting, taken from lots of different angles, and it would generate a 3D point cloud (with the original photos hanging in the space around it). I wondered if there was anything like that on the market today.

Turns out that photogrammetry freeware is a thing. I installed Meshroom and got my computer to start generating point clouds and meshes from moving shots of the castle. As you can see, these tend to be pretty rough; resolution, motion blur, lossy compression, dynamic range, and choices of angles are all limiting factors in terms of quality. But many shots still yielded data that I could use for reference in building the actual models.

Generating and refining these reference models takes lots of time and computing power, so this easily ate up at least a week in which I was doing no actual modeling. It was really one of my periodic returns to the information-gathering phase. In one Google detour, I stumbled upon some aerial footage of Alnwick Castle (one of the Hogwarts exterior filming locations for the first two films) and realized I could do more photogrammetry for that location, too.

Again, pretty rough. Nothing from these models is ever going to be directly included in the final project. They’re just a good way of collecting vertical measurements when no elevation drawings are available.

After spending so much time looking at shots of Alnwick, I felt compelled to start doing some actual modeling of those areas. I decided to start a separate model of Alnwick Castle itself; the plan is that I’ll eventually copy the appropriate segments over to the main model.

Lots of jumping around here; there are gaps in my references for certain areas, but I’m hoping to have more information soon. That last render – my most recent, from just this morning – gives a good sense for the level of detail I’d like to see in the entire model. (That part of Alnwick, the warder’s tower, was used as an archway leading toward the location of Hagrid’s hut in the first two films.)

Whew…that brings us up to speed on the current state of the project. Hopefully future posts will allow me to focus a little more on specific areas, since I won’t be summarizing a month’s worth of work all at once.

Like what you see? Got a question? Feel free to leave a comment. Otherwise, see you soon, I hope!