Finishing the COS Whomping Willow

Before we get into today’s post, I was asked to share a plan view of the original quad in my model, so…voila! Can’t make any guarantee of its absolute accuracy, but it should be close. (Still missing the terrace along the north side…I don’t have any good references for that.)

Anyway, in our last installment, I’d finished a rough sculpt of the Chamber of Secrets Whomping Willow’s trunk, roots, and major branches. But I decided it would be better to let Blender grow the newer, denser growth on top. I created a particle system to generate paths leading away from the tree’s knuckles. Negative gravity pulled those paths upward to create the right shape. Here’s an early attempt:

After adjusting the parameters some more:

It was at this point that I spontaneously made a work-in-progress video tour of the SS castle, which then morphed into a tour of the COS castle too. This has been up on YouTube for a bit but I’ll include it here in case you’re crazy enough to not have already subscribed there.

But anyway, back to the Whomping Willow. The next step was to add smaller twigs. I created a handful of different shapes and used another particle system to distribute them over the shoots on top. To keep the distribution from being unnaturally even, I painted a “weight map” to control the density. Looks kinda cool on its own:

But of course, the point isn’t to have the weight map look pretty. The point is to get the twigs in place:

Then I went back to the trunk and main branches to sculpt the final levels of detail, giving them a texture that hopefully resembles tree bark. This took a while. Lots of virtual scraping with my Wacom tablet. (For fellow Blender users – I did most of my rough sculpting with the wonderful Clay Strips brush, and then I adjusted the falloff of the Scrape brush to dig all the grooves into the bark.) In the next render, you can also see me starting to experimenting with procedural normal maps to add another level of detail:

Then it was just a matter of refining the coloration of the tree and texturing the rocks at the base!

That flat lawn texture doesn’t look horrible from a distance, but it’s pretty obvious that there’s no actual grass here when you get close like this. So I did something I’ve been meaning to do for a while: I used Blender’s relatively new geometry nodes feature to create actual blades of grass.

This was my first foray into geometry nodes. Initially, I just wanted to add blades where the lawn approached other objects (like the Willow). That way I could at least get rid of the hard edges but still keep my computer from blowing a gasket. But the performance seems to be better than with the existing particle tools, which is really exciting. I’d been worried about how to tackle the surrounding landscape if my computer couldn’t handle that many blades of grass, but this has me more optimistic. I went ahead and just covered the whole lawn with actual blades, and it seems to be working fine!

Anyway, here are some views of the complete COS Whomping Willow!

More updates to come!


22 thoughts on “Finishing the COS Whomping Willow

    1. Haha no, I’m excited too! Thank you! I was able to get results like that before, but it wasn’t very practical because of how much it hurt my computer’s performance. It definitely makes a difference to have the actual blades in there!


  1. Beautiful! Those shots are gorgeous. Makes me want a next gen video game with a movie-accurate castle. I appreciate Hogwarts Legacy’s creative liberties, but this gets me so nostalgic.

    I really liked the simple Flash-esque orthographic view of the training grounds from the last post (the one with the circle marking the site of the willow). I’d love more pics of that style in the future. The simple shading and textures help me really appreciate the layout of the designs. 🙂

    Looking forward to the next post. I wonder what’s next…


  2. It’s freaky how organic the tree is!

    How come the plan view’s background is so dark? And what’s that line going through the corner of the Quad and courtyard?


  3. Ya know, seeing the Whomping Willow where it is, it really makes sense why they moved it in POA. All those windows facing down on the lawn would really make it hard for four animagi to sneak around once a month.


      1. Right?? That thing is smack in the middle of what would be a pretty commonly trafficked area. But then considering the school’s history, student safety is never exactly a priority. 🙄


  4. Btw, since you’ve said you might do the landscaping down to the PS/CoS Quidditch pitch, have you thought about doing the PoA-onwards hillside past the stone circle that has Hagrid’s hut and the new home of the willow?


    1. I think I will most likely include that area, yeah. Even though it goes off the edge of the miniature, the steps down to Hagrid’s were obviously built to match the location. (Including his original hut will be harder, but I’d like to do that too.)


  5. I apologise for starting most of the comment threads on this one but more keeps occuring to me.

    You say more updates to come, which is very coy – any idea what’s next on the menu?


  6. You did a fantastic job on the tree. The grass looks super realistic, the geometry nodes are becoming really powerful. I look forward to using it myself.


  7. General question that doesn’t have anything to do with the Whomping Willow.

    I found a photo from a deleted scene from GOF where Dumbledore and Harry talk after being rescued from Mad-Eye (Barty Crouch JR.), which takes place in some roof of the castle, does anyone know in which part of the castle this could be? Or is it a similar situation to the Gray Lady scene in DH?

    Here is the link of the photo:

    Also, does anyone know in which tower is the Spiral Staircase/Divination Clasroom located?


    1. Most of the sets were built with no regard for the model, so they don’t really fit in neatly anywhere. The spiral staircase leading to the Divination classroom is actually the Dean’s Stair in St Paul’s Cathedral in London; it fits neatly into the Durham Cathedral towers, but there’s nothing in the films to suggest that’s where it’s meant to be. It’s just a coincidence of architecture. However, those two towers are on the north side of the castle so it would sort of jive with the book-canon where Divination is in North Tower.


    2. I believe the the deleted scene balcony was intended to be the DADA tower. It takes place right after Dumbledore and Harry walk away from Rita in the DADA classroom, then they go on this balcony. But the balcony itself is not part of the miniature at all.


    1. Haha just because I haven’t posted in a week? Don’t worry…I’ve hit a major milestone today, and I’m working on a post AND a video about it. Just not ready yet. 🙂


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