Rescaled Bricks & Greenhouse Dragons

I promise we’re going to get to sculpting the decorative dragons from the tops of the greenhouses, but first I wanted to share a “before and after”. A reader who goes by kronkolweg pointed out that my castle’s bricks were a little big. It had already been starting to bug me a bit, and this was just the kick I needed to get off my butt and fix it.

For the original castle miniature, one or more brick textures were hand-sculpted, molded, mass-produced in FastCast resin, and glued to the miniature’s wooden understructure before being hand-painted. There was a transition to more detailed plaster-based textures starting in Chamber of Secrets – I’m not sure if any of the original resin brick textures ultimately survived through to the final Half-Blood Prince iteration of the miniature. In any case, the overall effect is the same, and my procedural brick material mimics it without requiring me to individually texture each wall. The thing is, when I created this material (as documented here, here, and here), I had much less of the castle built, which meant I had fewer points of comparison for the scale of the bricks. Frankly, I don’t remember how much actual measurement there was, as opposed to simple eyeballing, but it’s become clear that the results are a little oversized.

So, being the Excel nut that I am, I sat down and made a spreadsheet. I took horizontal and vertical brick counts for various areas of the castle, comparing my model to the miniature. There’s a certain margin of error in the scale of my castle, and the bricks of the miniature are not necessarily of completely uniform scale, so I averaged the different measurements and arrived at my brick adjustments: a 34% reduction in width and a 21% reduction in height.

The interactive sliders below compare the old larger bricks (left) to the new smaller bricks (right):

The difference is subtle from any real distance, but it’s more accurate now, which always feels good.

With this tweak completed, I shifted my attention to those greenhouse dragons! Fortunately, they’re all identical, so I only had to sculpt one. I did so in a separate file, and – well, if you’re interested, just watch part 1 of the video.

Frankly, I can’t get enough of these sliders, so let’s compare the base mesh to the full-resolution sculpt…

…and now comparing the full-resolution sculpt to the retopologized version with normal mapped details:

If the differences seem really minor…good! The point of retopo is to vastly simplify the geometry, which makes the asset a lot more manageable. The sculpt on the left has over 1.3 million faces; the retopologized version on the right only has around 1,500. Much easier on the computer! Of course, that eliminates a lot of details; baking and applying a normal map is a way of faking those back in, hopefully with an end result that’s nearly indistinguishable from the original sculpt. (In this particular case, there are a few small artifacts in the shading, but these are not noticeable when color is applied and we move the camera away a little.)

You can watch this whole process in part 2 of the video:

The retopology process is still a lot slower, harder, and more frustrating for me than I’d like, but in the end I was satisfied with the result, so I created an appropriate material, brought the mesh over into the main castle model, and duplicated it to the appropriate spots on the single greenhouse I’d already created. Voilà!

That’s a wrap for the dragon, and for this greenhouse overall! The next steps will be to duplicate this greenhouse and create the other two design variations on it. Then I’ll be able to move on to the domed conservatory, the curtain walls surrounding the greenhouses, and hopefully some ground cover and footpaths. Be sure to subscribe to this blog and the YouTube channel for updates as they come!

SS/COS Moving Stairs, Continued

Let’s take a detour back to the moving staircases of Hogwarts! Thus far, as seen in this post, the environment has been very generic – just a tall rectangular space of the correct dimensions. Let’s fix that.

The biggest problem – we’re talking physically biggest – is that there’s supposed to be an extra chamber in the bottom section where the big window goes. Even if I’m not going to add the window yet, I can at least add that chamber:

Notice also the addition of a blue screen floor. This sits at the floor level of the actual set and also corresponds roughly to its footprint. Below that, I’ve lowered the main floor to reflect the slightly greater depth of the miniature. This is important because I won’t have room for the whole window if I leave the floor at set level. (The window only existed in the miniature, as far as I’m aware – though that changed in the redesigned Prisoner of Azkaban set.)

Next step is to hide the blue screen floor and add the lamps that help light the space:

(None of this is intended to look as realistic as the main castle model…the materials are very basic and these are just quick renders with Blender’s Eevee engine, which specializes in speed at the cost of physical accuracy.)

With lamps in place, let’s start adding the passageway that leads to this room from the Great Hall/Chamber of Reception area. (This was not part of the miniature as far as I’m aware, but it most definitely was part of the set.) This area is interesting because the production design draws very heavily on the real world – specifically, the steps at Christ Church Cathedral at Oxford, where the Chamber of Reception interior scenes were shot. You can see this most clearly with the large stone arches, which were built to match the ones at Christ Church, tying the sets and location shoots together into one shared imaginary space. The doors to the Great Hall set use the same arch design as well…a fact I’m grateful for, since the Warner Bros. Studio Tour was kind enough to post detailed drawings of those doors. You can see the same design on the castle exterior model as well, though I haven’t built those parts yet.

As always, things start with a confusing mess of intersecting curves that gradually coalesce into something more recognizable:

One of these arches is used as the entryway to the main room with the moving stairs:

Nice to be able to duplicate the design as needed:

Those rather ghostly outlines are caused by the same “backface culling” feature that allows us to see into the rooms from outside.

With more walls, details, and openings coming together, this area is starting to look quite a bit like the set…

…minus all the paintings, of course. As I see it, I have three basic options with those. In order of increasing difficulty:

  1. Pull a Filch and omit them entirely.
  2. Scatter the walls with a variety of paintings that look right overall.
  3. Try to match the paintings seen in the films, frame by frame, painting by painting (and fill in the gaps with option 2).

I’m currently sticking with option 1, but who knows?

In any case, there’s still more work to be done here. I need to add the rest of those smaller arched openings throughout the room, and I need to add the large, ornate window on the opposite side. Look for those in a future post! I also still hope to do some videos and scale comparisons and whatnot once this side project is complete. I might need to invest in a new GPU before then, since my current equipment is crashing if I try to render any more lamps with Eevee…

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!