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.