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!

The Beginning

All my life, I’ve often found myself tumbling headlong into unusual obsessive hobbies. In January 2019, I tumbled into a new one. I was struck by the realization that Hogwarts Castle underwent a number of design changes over the course of the Harry Potter films, and I wanted to be able to watch a time-lapse of those changes from a stationary vantage point. Any stationary vantage point. The only solution was to create a 3D model…of all 7+ versions of Hogwarts…in my free time.

So I got started.

I have no idea how long this passion project will go for – I do tend to jump between my different interests quite a bit – but it’s been a good time so far, and I thought I’d share my progress with any likeminded fans of the Potter franchise, cool architecture, and/or 3D modeling.

Have fun perusing!