Sculpting A Detailed Body Anatomy At CGMA

Introduction

Hi, my name is Kristian Weinand. I'm currently working as a 3D-Artist for XR-Experiences at the Leibniz Supercomputing Centre and as a 3D-Modelling teacher at the LMU Munich, where I also graduated from Fine Arts and Multimedia program a little over a year ago. During my studies there I specialized in 3D-Modelling and created a short animation for my graduation project. I wasn't entirely satisfied with my skill level at the time and realized I still had a tremendous amount to learn, right down to the very basics of artistic creation. And I also knew I had to specialize further to become really good in a specific field. The main focus of my art has always been characters, so this is definitely where I want to go, but I had never really sufficiently studied anatomy. So I decided to enroll in Anatomy for Production class with Christian Bull at CGMA.

CGMA Workflow

First of all, I have to say that it was an amazing course with an excellent instructor. Christian's always very calm and took his time to properly explain all the areas of the human body in detail. Of course, the topic is ultimately complex and there's always something that will not be covered but overall I'm very satisfied with the class and what I got from it.

For the class we were supposed to create at least one entire human model in an anatomical pose in ZBrush, building it up from a basic proportion blockout over the skeletal system, muscles, fat, and skin over the course of ten weeks. Each week we focused on a different body part, creating first the bones and then the muscles on top for each body part. There were also some special weeks with different topics at the beginning and end of the class.

If we wanted, we could create another model with different gender and/or pose. I wanted to make the best of the class and decided to create four human models, male and female both in anatomical poses and another more dynamic pose. I consider my male posed model to be my main project from the class as I picked a really dynamic pose for him that was definitely the hardest one to do. But it was also the most fun project and I loved the tension and expression in the pose right from the beginning when I found the reference for it.

The techniques used in the course were pretty simple. We worked in ZBrush all the time and used basic sculpting techniques, simple shapes for the blockouts, then mostly working on separate pieces, adding muscle masses where needed. I DynaMeshed my models a lot, Christian doesn't like DynaMesh too much, so he used more of a ZRemesh and Subdivide approach, but that was all up to us how we wanted to approach that. A problem I had with my DynaMeshing was that areas that were very close together (like the arms right next to the torso) were always merged. But that didn't bother me too much as the models were supposed to just stay in that one pose. But a different workflow might have avoided that. Also, ZBrush gets a bit slow when DynaMeshing at high resolutions and my PC isn't the best. I know lots of people just DynaMesh on lower resolutions and then subdivide, but it's just something that I like to do as long as I'm still adding limbs and such.

First Week

The first week's exercise was very fun and liberating. Christian provided some models of made-up skeletal structures, nothing that reflects actual existing anatomy. We were supposed to think about functional anatomy and place muscles on the bones accordingly. We learned about antagonistic muscle groups and basic organic design principles. The results among the students were very diverse and it was interesting to see what everyone came up with. I also noticed that I wasn't entirely able to forget what I already knew about human anatomy and stuck a bit too close to normal human musculature in areas that I knew about. Christian used this week to give us some basic understanding of how anatomical shape language works and how we make our sculpts look natural. He gave us tips like avoiding completely parallel lines, losing and finding lines, all things that I didn't really do sufficiently in these sculpts but it helped loosen up a bit and get in the sculpting mood.

Second Week

The second week was about a simple proportion blockout to test the poses and get the overall proportions about right. So we already had to pick our poses at this stage. Proportions are something that I usually just eyeball, so although being rather basic this part was very valuable for me. I also used the second week to sculpt faces for my models. Of course, the figures needed some kind of head but we didn't have to go too far with the details here. Faces aren't part of the course (there's a different class for that at CGMA) and they are definitely so complex that they deserve at least another ten weeks of extra study. Still, I would have liked to go over that a bit more in this class. The calm face for the anatomical pose didn't fit the posed male sculpt anymore at a later stage to the point that it got almost comical, so I made another head for him later.

Reference is massively important for anatomy (as for any other topic to be precise). I had a huge PureRef-File that contained everything Christian provided for us as well as other drawings, sculpts from other artists and photos for various body parts. I just extended a file that I had already previously filled with anatomy references and I just threw everything else in there. I would definitely advise everyone to not do that and get some proper order in their reference files. PureRef can handle a lot but if there are too many images in there it'll start lagging. Also, you probably won't even use everything you throw in the file. 

Weeks 3-4

The next two weeks were about different aspects of the torso, the chest, abdominal area, back, and neck. It was again up to us how far we wanted to go with the detailing of the bones. You usually don't get to sculpt too many skeletons, so I wanted to at least use this chance to learn a bit more about the shapes of the vertebrae and such. Even if it doesn't really help the overall shape later it's still super fascinating to study how complex our body structures actually are. Hips have a crazy difficult shape, so they gave me some trouble but again it's just fascinating to understand a bit more about how these shapes work. 

The video lectures on this and the following weeks were massively detailed and valuable. Christian was able to point out details that I very likely wouldn't have spotted on my own. Things like at what angle the muscles are arranged on the limbs, what structures give shape to the back, which shapes will actually be visible, and which will in most cases be covered by fat or will just be very thin.

Especially the back was something that I never really understood before. For example, the latissimus dorsi is this very flat but large muscle that you will always see in anatomical drawings but it's very thin so that it actually doesn't show by itself but will let you see the underlying structures like the lumbar muscles. Another structure that gets easily overseen because it lies underneath is the rhomboids. They attach to the spine and the shoulder blades and lie underneath the trapezius but they are very visible in certain poses when pulling the arms backward and the shoulder blades together. Those things are super important but a bit hard to learn without good guidance with an experienced eye. In the assignments for each week, he repeated what to especially look out for while working on the specific areas, which helped focus on certain important parts.  

Weeks 5-8

The next four weeks were about arms, hands, legs, and feet. Again with the same approach, first refining the bones, then adding the muscles afterward. The arms and legs are areas that I still struggle with, especially the lower regions. There are just so many small muscles that it's hard to memorize and when the forearms are twisted it gets crazy. But it's manageable with good reference and some time to wrap your head around what's going on where. You might think that those many little muscles aren't visible anyway but it's the small details that might still be seen, like the ridge of the ulna, or where the triceps turns into the tendon, that adds so much realism to the model. A thing I learned here was the importance of a good silhouette and how the muscles form it. Which muscles have more volume, which turns into tendons at what point and where the specific muscle starts on the bones.

It was very helpful to the learning process to sculpt everything four times. It also took a very long time, so it was quite busy ten weeks. And I really noticed how I got better and faster with every iteration. Some parts I could recycle, like the bones which always keep the same shape of course and I also just copied and slightly modified limbs that were in roughly the same pose.

One thing I learned and had always overlooked somewhat in my prior anatomy studies was the influence of bone on the shape of about every structure on the human body. Of course, bone shapes the entire body and holds everything where it's supposed to be but I completely neglected that some parts of the body are almost entirely a bony mass. Hands and feet are always parts that people seem to struggle with. For me, it was especially the feet, because I hadn't really studied those properly before. You usually need to give a character hands when drawing or sculpting, but feet are just hidden in shoes most of the time. But with the workflow we used here, bones first, then muscles on top, I realized that hands and feet are both very bony structures, so once you got the bones about right, you were about 80% there and it was actually almost easy. The same thing for the rib cage, it shapes the entire upper body. The hips are somewhat different though. You see some bony parts poking through to the skin, like the iliac crest and the ASIS (anterior superior iliac spine) and PSIS (posterior superior iliac spine) but overall the bone is pretty much hidden with large muscle and fat masses on top. But it was still super interesting to study how hip bones are shaped. Humans have crazy complicated hip bones and that was definitely one of the more difficult areas to sculpt.

It's also funny how you start to look at people differently and marvel at the wonders of human anatomy in your daily life while studying anatomy intensely.

Christian's lecture videos were fantastic. He first explained the bones and muscles using color-coded drawings, then he proceeded to show the just mentioned skeletal and muscle structures on very patient and professional live models, which was very valuable. He had a male and a female model and later even some more models for different body types. On the models, he could also show how muscles change in motion and how they behave in different positions, which was fantastic.

After that demonstration he proceeded to sculpt the bones and muscles, exactly explaining what he was doing. I was very impressed that Christian didn't use symmetry at all while sculpting. It definitely adds to the practicing effect but I didn't do that, my sculpts are entirely symmetrical (except for the posed ones).

The lectures were very long each week, something around three hours but packed with knowledge and providing that in three different forms. This is not the only class I've taken at CGMA but it was definitely the one with the longest video lectures and the most effort going into producing them I would say.

His feedback was also very valuable, probably the most important part of every CGMA class. Christian really took the time to look at the models and sculpted over them quite a bit. My male-posed model with the raised arms gave him some trouble because it's just an extremely difficult pose with the arms raised and turned backward. But he looked over it each week and helped me a great deal finishing it, which I'm super thankful for. I almost feel a bit sorry for giving him so much work but I have to say he's an amazingly invested teacher and I highly recommend taking his class if you're thinking about doing so.

Week Nine

Week number nine was very interesting. We took our finished sculpts from the last week and changed the body types by varying the amounts of body fat and muscle mass. It was actually faster and easier to do than I expected because all the groundwork had already been done. I just had to add fat in the right areas, add muscle mass or carve away a bit of it. We did this with layers and morph targets, so we could use the sliders to see the before and after and everything in between. I made four more body types for the male anatomical pose and one for the female. And of course, this doesn't cover the extent of variation in human body shapes, the bone structure and overall proportions stayed the same for all of these models. And here it was also quite interesting to see how drastically a body can change while keeping the same skeleton. It's practically the same people under very different living conditions.

The Last Week

Week number 10 was the last week of the class and we were supposed to finish all our sculpted figures. But this week wasn't any less challenging than the rest. Our second assignment was to take everything we had learned over the class and apply it to yet another new human figure in a speed sculpt. Christian said it shouldn't be more than three hours if I remember correctly but I didn't like my result after three hours enough to present it, so I took another one to two hours to get it to a level that I was satisfied enough with to show. I actually planned to finish it properly after the class but haven't done so until now. It was yet another dynamic pose with a lot of tension, I guess I just like those the best.

After the class, I took some time to properly finish the sculpts, give them some accessories like the sword (he was holding a simple cylinder for a long time), cover them up where necessary, and give them a proper presentation setting with lighting and simple materials. I did the first iteration of renderings in Arnold in 3ds Max and the second (which you can see here) was done in Blender, which has gotten really fantastic over the last months.

I've also taken the Animal Anatomy class at CGMA a few months after this class and it was especially interesting to see how basically the same anatomical structures vary on humans and other animals. We all share the same anatomy, it's just a bit different on every animal. It was a very enriching experience to study these things thoroughly in both of these classes.

Recommendation for Beginners

As I already mentioned I would absolutely recommend taking the class if you're thinking about it. It's definitely intense, so you should be able to make room for it in your schedule. It's not something that can easily be done over the weekend if you want to really take something from it (but you also don't need to sculpt four characters at once of course). Something that I really like about the CGMA classes is that you get assignments with strict deadlines every week, so you have to get things done on time. I'm never as productive as when I'm taking a class. So it's also exhausting, but it's definitely worth it.

Something very important that I learned from the class and maybe also over the course of my former studies was that no matter how good you get at using any kind of specific software, it is still the most important thing to know your solid fundamentals. Software changes over time and you'll always have to adapt to an ever-changing environment. But what will always stay with you is your fundamentals. If you properly studied human proportions, bone structures, and musculature you'll always be able to reference that and use this knowledge no matter what you do. People will probably not be able to tell whether you sculpted in ZBrush or Blender but they will immediately be able to tell when just a tiny bit of the proportions are off. And this is also what will empower you as an artist, it's not knowing every single function of a software package but the solid design foundations of nature that will ultimately help you to create whatever you want to.

Kristian Weinand, 3D Character Artist