Creating a Symbiote Character with Tentacles & Damaged Skin in ZBrush

Introduction

Hi, I’m Teemu Hartikainen. I’m currently working as a 3D Character Artist at Krafton Europe Amsterdam. I first discovered Blender around 2008 and learned some basic modeling, but my focus remained more on the traditional art side, like drawing and clay sculpting. In 2014, I began studying industrial design, which brought me back to 3D with software like Rhino and Solidworks. Around that time, I also rediscovered Blender and started exploring it deeper. 

I started freelancing during my studies in graphic design, motion graphics, and photography, and gradually shifted my focus and client work into working with 3D characters and creatures to make an effort to work fully with film/VFX or games. In 2021, I moved from freelancing to full-time game development as a character artist. I remember worrying if working in the other art-related fields was a waste of time, but in hindsight, I think it actually gave me a lot of perspective and helped me to develop as an artist. So for anyone interested in the field, don’t be afraid to take detours!

Inspiration & References

This project is based on artwork made by Santiago Betancur. I was inspired by the movement and composition of it, and thought it would be a fun project to sculpt the surface interactions and dynamic composition.

I began by collecting anatomy references from 3D scans and benchmark creature artworks to establish a clear goal in mind for how I would like to present the character in the end. During the project, I added some LookDev shots with draw-overs to help improve the composition and materials along the way.

Modeling

High poly progress

Before starting the blockout, I thought about the different approaches I would take for this project. I knew I wanted to have a single pose for it, so it made sense to start sculpting in the final pose. While I usually like to sculpt everything from scratch with personal work, this time I started with a simple base mesh, which I used to get the pose roughly right, after which I brought the model to Blender to get the tentacles in early on. 

The reason I wanted to do this part in Blender is the versatility of the curves. Making a mesh with a simple tentacle shape profile and deforming it with the curves, I was quickly able to create a nice base mesh for sculpting. I also generated vertically laid out UVs for each tentacle, which allowed me to add some generic noise and perfectly aligned wrinkles in ZBrush surface noise maker. This gave me a nice base mesh for the tentacles.

Alternatively, with this workflow, I could have saved time and just sculpted one finished tentacle to reuse it for the rest of them, but I wanted to do most of the sculpting individually in ZBrush. For personal work, I like to save time where it matters, but take my time on the fun stuff.

I also sculpted a complementary blending mesh between the head and tentacles. This helped me integrate the tentacles better into the mouth and gave it a more layered look.

I have a weird habit of creating a new eye from scratch for each of my personal projects, and this one was not an exception. While a bit futile, I guess it’s nice to add a more personalized touch to each character.

The rest of the high poly stage was straightforward sculpting, focusing on the interactions between the tentacles and skin. Every now and then, during the high poly phase, I like to bring the model to a rendering engine such as Marmoset to get a better read on how to model works with different lighting conditions. If you haven’t yet, give it a try!

Retopology & Unwrapping

One of the areas I like to save time on personal work is topology. For this one, I ZRemeshed the model when all the bigger important shapes were set in place. One technique I often use to get better control of edgeflow is setting up polygroups and ZRemeshing with the keep groups option on. For tentacles, I got away with using the mesh exported from Blender as the lowest subdivision, but for the rest of the parts, I used this method to create the meshes for sculpting with subdivisions.

After finishing the high poly sculpt, I brought the lowest subdivisions to Blender to create UVs with 5 UDIMs on the body, and 6 for the tentacles to get a nice amount of texel density.

The UV-wrapped meshes can then be imported back to ZBrush, and since the topology is the same, the UVs can be easily transferred from the wrapped mesh to the subdivided mesh with the UV Master plugin. This allows me to export any subdivision level of the mesh, and it will have the same UVs I created for the lowest subdivision.

Usually, I like to use displacement maps to get the detailed silhouette of the mesh in the final image, but this time I decided to do it another way. I took the highest subdivision level of the model, and decimated it from 35 million polys to a much more manageable 400k polys with the keep UVs option on. After this, I baked the remaining details from the non-decimated mesh in Marmoset, and I was ready to move on to texturing.

Texturing

Before starting the texturing process, I always begin with taking a good look at the reference board and start working iteratively by lookdeving the textures in the final rendering engine. For this project, it meant going back and forth between Substance 3D Painter and Marmoset Toolbag 5.

I wanted to help sell the effect of tentacles coming out and going under the skin with the textures. For this, I painted some darker colors around the thinner skin to create a bit of that see-through effect. I emphasized the stretchy areas of skin with some lighter yellow tones and reds and purples for more inflamed and bruised areas. I also painted some fluids coming out of cavities and around the tentacles to integrate them better and get that roughness breakup.

Lighting, Rendering, & Post-Production

For some extra bit of realism, I wanted to take full advantage of Marmoset 5’s new groom support by making a full body groom and long hair in Maya Xgen. It’s a subtle effect, but I think it adds a nice touch to the final image.

I also created transition meshes around the eyes and the tentacles. This technique is usually used to make the eyes look more natural, adding the “tearline.” I applied the same concept to the tentacles. I modeled these meshes in Blender using surface snapping and applied a refraction material to them in Marmoset. To help these blend a bit better in the render, I disabled shadow casting from them in the mesh settings in Marmoset.

For the final touches, I made the shiny floor and blood decals to give it a subtle amount of environment for the final picture. I made multiple different light setups, starting with the main keylight with a subtle environmental HDRI to find what I thought was the best result, then adding complementary spot- and omnilights, trying to direct the eye to the most important areas. Finally, I added some background smoke in Photoshop for the stills and in After Effects for the video.

Conclusion

I think making the final model and sculpting were the biggest challenges in this project. Building the different forms and surface interactions was a good exercise and underlined for me how important proper planning is to avoid getting stuck midway or getting overwhelmed by the complexity of the model.

I think the amount of unique shapes and the goal to have a nice composition with them in the end pushed me to find solutions that made the process as streamlined as possible. Planning almost every step forward at the beginning made the whole process much more enjoyable and easier than I thought. Once the final model was completed, the rest of the process felt straightforward, and mostly adding stuff piece by piece, I felt would enhance the final result.

Teemu Hartikainen, Character Artist