Comprehensive Tutorial on Modeling & Texturing a Dragon in Houdini

Introduction

Hi! I'm happy to be back with a little project breakdown. A few words about me: I live and work in Vancouver at DNEG as a Texture and LookDev Artist. I also work as a surfacing mentor at PIXL VISN in Germany and as a teacher and mentor for texturing at VIA University in Denmark. For me, surfacing is about telling a story and breathing life into an asset. 

About the Sorindar the Gray Rock Dragon Project 

The project started with the intention of making learning materials for my students, and I came across the very cool kite model by Clément Béziers on ArtStation. For me, it was the perfect asset, as it has hard body and soft body materials and is not too complex but still interesting. I messaged Clément Béziers on Instagram, and he didn't hesitate for a second and agreed to send me the model. This shows once again how incredibly supportive the 3D community is! 

The Model 

The first thing I did was adjust the UVs a bit and spread them over a few UDIMs to give my textures more resolution. Then, I projected the high-poly details back onto the newly UV-mapped model in ZBrush and exported it as a Displacement Map. I really liked the topology. Clément Béziers did a very good job here.

Surfacing

The first thing I did in Mari was to import the ZBrush displacement and make all the geometry bakes with the high poly. The new baker in Mari 7 is extremely fast and delivers very good results. I much prefer it to Substance 3D bakers.

I always start creatures and characters by painting the Displacement Map first. Many details in the color can be derived from it later, and the surface texture plays a big role in organic assets. For this, I use Channel-Packed Maps from Texturing XYZ. After I create the displacement details, I export them and start with the lookdev in Houdini and RenderMan. 

I like to use a mid-gray to set the displacement details. This helps to not get distracted by color and reflection details. 

Then, I start with the big color regions and place them on my asset. Then, I use the geometry bakes to make color breakups and also support the asset shape with them. This also has the advantage that it is procedural, and in case of notes in production, it would be easy to adjust or if there was a model update. 

Then, I use high-resolution tileables to bring the small details into the textures. Here, I also like to use geometry bake sum to define where there is more or less of it. Of course, the whole thing is rounded off with some hand painting. 

I also create various masks to have in the lookdev, which I set up in parallel and thus have a back-and-forth between Mari and RenderMan. After the colors are made to look good in the lookdev, I take care of the other Maps, like Roughness and Specular Weight, and so on. This brings a bit more complexity to the whole material.

After the asset's base material is defined, I create a second set of textures—the so-called dirt layer. This layer contains a new Diffuse, Roughness, and Displacement Map. It is then overlaid in the shader with a new material and masks. This gives me the flexibility to customize the dirt material the way I want it without affecting the underlying materials.  

I use the LAMA material system in RenderMan for shading. I really like the flexibility it offers. I also think RenderMan is a very good engine that produces very nice results, and the Displacement Layer nodes are my personal favorites. 

Lighting

The lighting setup is rather simpler and consists of just two area lights and an HDRI dome light. I wanted a somewhat harsher light to emphasize and support the shape of the asset. So, I made a rather strong rim light and made the key light somewhat narrow to get hard shadows. The HDRI functions more as a fill light. 

Compositing

I did the compositing in Photoshop. I have been using this tool for over 10 years and know exactly how to achieve my desired result. But for an animation sequence, I would use Nuke. The compositing wasn't really much work, as the result from RenderMan was already very good. It was just a bit of exposure and contrast and adding a background to the image and a super slight color grading.

Johnny Fehr, Texture & LookDev Artist

Interview conducted by Gloria Levine