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Mastering the Sculpt: Unveiling the Secrets of Torso and Back Muscles for a Perfect Physique


💪🏻Learn about the anatomy of the human torso and back muscles, including chest, abs, obliques, and sculpting techniques for different body types.




💪🏻Learn how to sculpt the anatomy of a body mesh by merging subtools, refining muscle groups like abs, chest, obliques, and back, and adding clay buildup for realistic details.








Torso and Back Theory


  • In today's class, we’ll be sculpting the torso muscles, chest, abs, and obliques as well as the back muscles.

  • First, we’ll look at the Anatomy of the upper body muscles to have a better understanding of how we can sculpt them.

  • The book we’ll be looking at is called Anatomy for Sculptors and not a biological anatomy book. We highly recommend taking the time to read through the book to have a better understanding of how you should sculpt muscles.

  • We’ll look at the front muscles first and see how they’re all layered on top of each other.


  • The image we want to focus on is the second image with the skeleton and the Saw Muscles.

  • These muscles are located on the sides of our ribcage and are most noticeable below the chest area.

  • On top of the Saw Muscles are the Chest Muscles.

  • They have a sideways water drop shape and cover most of the chest.

  • Not everyone has the same shape of chest muscles depending on how their anatomy is.

  • The Baraudest Back Muscle is located on the back but it also can be seen from the front and it covers most of the Saw Muscles from the sides.

  • This muscle is most noticeable in bodybuilders and more bulky characters.

  • The Trapezius Muscle is located behind the neck and covers parts of the back. It is mostly known for its diamond shape when you look at it from the backside.

  • We got to see this when we were doing the 3D Reference Blockout of the male anatomy.

  • The Deltoids are the shoulder muscles, we’re not going to talk about them too much in this class and will work on them more in the next one when it's time to sculpt in the arms.

  • The Obliques are the side muscles in between the Abb muscles.

  • The Abb and Oblique muscles are the most noticeable upper body muscles when you sculpt a character especially if they are relatively buff and fit.

  • The Abb muscles are also the hardest ones they get right.

  • From the back, we can see the Saw and Oblique Muscles since they wrap around the rib cage and peek onto the back.

  • There are a lot of small muscles on the back that connect with the bones in our arms.

  • They’re not that big but still important to keep in mind when sculpting the more braud muscles located on the back.

  • One of the broadest back muscles is the Trapezius.

  • It covers most of the top part of the back and the entire back of the neck. Its diamond shape makes it easy to get the shape of it down fairly easy.

  • Another distinct feature of the Trapezius is the line that goes through the middle of it.

  • The Braudest Back Muscle wraps around the lower part of our back, covering most of it.

  • It is a bit tighter and firmer than the other back muscles we have since it helps us a lot to do most of the labor intense movement.

  • The Buttocks are also part of the back muscles but we’re going to discuss more of it in another class.

  • The Clavicle bone gives a lot of character to the body.

  • They extend out from the middle bone stretching out towards the shoulders.

  • They are not straight bones but in fact, have a curve that gives it a sort of an “S” shape.

  • The shape of the Clavicle also resembles that of a bow.

  • Just like the book says, the collar bones are less noticeable the more muscle the body has.

  • But there is still that gap between the Clavicle bone and the Trapezius muscle.

  • It’s important to keep in mind that the Chest muscles go inside the shoulder muscles.

  • In female anatomy, there are two fat tissues hanging on top of the chest muscles that form the breasts.

  • This means that the chest muscles and breasts are two separate things and are not one of the same.

  • The shape of the breast can vary from small to extra large.

  • The theory behind sculpting any size of the breast is still the same, the beginning of the breast or the top part will always be leaner while the bottom will be rounder.


  • The Trapezius Muscle is most noticeable when it’s being flexed and when there is more muscle mass

  • The Saw Muscles are also very much noticeable from the front even though they are mostly covered by the chest muscle and the braud back muscle.

  • Most people mistake the lower parts of the Saw Muscle for ribs.

  • The Saw Muscles are also connected with the Obliques just like in this image.

  • Going back to the Obliques, we can see that on males these muscles have a rounder shape while on females they rest nicely on the hip bones.

  • As we mentioned previously these muscles can give a lot of personality to your character.

  • From the side, we can see that the Obliques separate the upper torso from the rest of the body.


















Fat Pads

  • Fat pads are areas of the body where there is a storage of fat.

  • On the male body we can see in the image these fat pads are located under the Buttocks, behind the legs, behind the knee, below the armpit, around the crotch, and right below the Oblique muscle.

  • In The female anatomy, there are a lot more fat pads.

  • The breast themselves are a large tissue of fat that hangs from the chest muscles.

  • We can see more of these fat pads on the crotch, in the inner thighs, on the hips, above the hips, a lot more around the knee, directly on the Abbs or on the stomach, on the buttocks, below the buttocks, and around the hips area.


Sculpting Torso Anatomy


  • We’ll be working on the male block out we did for the 3D Reference Blockout.

  • Before we merge everything we need to hide the 3D Reference so it doesn’t merge itself with the blockout.

  • Another thing we can do is fix up the torso a bit.

  • The Torso shouldn’t be just a flat square but it needs to have a diagonal from to it.

  • Use the ClayBuild up brush to add and remove clay away from the model.

  • When we click on the merge visible option a new PolyMesh3D will appear above our Subtool.

  • That’s where all our merged parts are.

  • Before we DynaMesh we can use the Move Topology Brush (BMT - shortcut) to move the arms a bit away from the body so when we DynaMesh it, the arms won’t accidentally stick to the torso.

  • The Move Topology Brush only moves one polygroup at a time.

  • Since our body isn’t DynaMeshed yet, all of the parts on block out still have their own polygroups.


  • After we move the arms away from the body a bit we can then DynaMesh it on a higher resolution so we don’t lose any of the minor details.

  • We don’t want to have too much Active Points because it will be harder to manipulate and edit the form.

  • We also need to smooth out the body after DynaMeshing but not to the point where we lose the details.

  • We can go back to the 3DMesh where we still have all of our parts from the blockout separated, copy our 3D Reference, and then paste it into the PolyMesh3D where our blockout is fully merged.

  • We can see that our blockout is thinner than the Reference and that is ok since we are going to build up the muscle and it will catch up with the size and mass of our Reference.

  • Now that we have our Reference we can start using the DamStandard Brush to line out some of the main and most noticeable muscles like the Trapezius and the line that goes across the entire back.

  • We also want to add the diagonal lines on the Braud Back muscle since it does kind of fold in on itself.

  • From the front, we can fix up the arms a bit by using the Move Brush and aligning it better with the 3D Reference.

  • We’re going to start off by sculpting the Chest Muscles since they are the most noticeable muscles on the front of the body.

  • Using the DamStandard brush start lining out the muscles.

  • Remember, the chest muscles fold under the shoulder muscle. We mentioned this in the Torso and Back Theory.

  • Using ClayBuild we can start adding clay to the chest muscles to create more volume.

  • The chest muscle is linear on the top and curved on the bottom and sides.

  • This happens because of gravity, it is pulling the muscle down and creates more mass on the bottom of the chest muscle.

  • The Clay Brush is good for sculpting out muscles since it gives us a nice texture at the end but it is also ok if you just work with the ClayBuild up Brush.

  • Use the DamStandard Brush to split the muscles underneath and define the shape a bit.

  • After you’re done with adding in the clay make sure you smooth it out.

  • Moving onto the abbs, we’ll use the DamStandard Brush to draw out the shape and where each abb muscle is located.

  • The last abb muscle needs to be longer than the other ones just like in out Reference.

  • Using the ClayBuild up brush start adding in the clay to form the muscle.

  • The abbs, just like the chest muscles, are bottom-heavy muscles.

  • This means that there will be more volume on the bottom of the muscle and less on the top.

  • This doesn’t apply to the last abb muscle, this one has muscle mass spread out heavenly across it.

  • While we are shaping out the abbs we can start to add in clay and block out the Oblique Muscle, adding 3 strokes on the sides of the abbs and one bigger stroke on the hips.

  • We saw that the male anatomy has a curve at the end of the Oblique muscle where the hips are. Make sure you have that gap where the hip bone is.

  • Make sure that the body isn’t too flat from all sides. If you need to use the Move Brush with a large brush size to fix up the form by dragging out part of the body.

  • With the Dam Standard Brush, we’ll make small holes beneath and around the abb muscles, after which you will use the ClayBuild up to add clay around the lines we made.

  • After we are done with the abbs we can DynaMesh the body and smooth them out.

  • From the side, using the DamStandard brush add in the lines where the Saw muscles are peeking out.

  • Using the Move Topology Brush we can widen up the body below the armpits to make the back a bit wider.

  • After we’re done with the block out of our front torso we can DynaMesh the whole body, smoothing out the front before using the DamStandard brush to define the form.

  • If your abbs or stomach are curved you need to straighten them a bit by using the Move Brush and dragging out the stomach till it isn’t no longer curved.

  • Using the Clay Brush we can make the shape of the muscles look more organic by subtracting and adding clay to our model as well as lightly filling up some of the dents we’ve made.

  • If we fill up the muscle too much and it disappears we can always use the DamStandard brush again to re-define the shape.

  • For the collar bone, we know that it starts from the middle bone and stretches out towards the shoulders.

  • When we look at it from the top it should have an “S” shape.

  • Right behind those bones, we need to have a small hole in front of the Trapezius muscle.

  • With ClayBuild up take away some clay and then smooth it out.

  • After we make the hole we can use the DamStandard to add two lines on the side of the neck then fill the middle with ClayBuild up to make the neck muscles.

  • Here we’re quickly going back to the Obliques to fix up the shape a bit.

  • The muscle was sticking out too much so we fixed it up by taking away some clay, defining the form with DamStandard, and smoothing it out.

  • Going to the back of the body we’ll start adding clay on the Trapezius and on the bottom muscles below the same muscle.

  • We can take this time to add some clay on the shoulders and split them up into 3 pieces by using the DamStandard brush.

  • The shoulder muscle has 3 distinguished muscles making up the entire shoulder muscle.

  • We don’t need to define the form too much since we will make the arms and legs in a different class.

  • For now, we just want the overall shape of the shoulders.

  • If the shoulders are too pointy from the front move them with the Move brush.

  • Add some more clay on the two muscles below the Trapezius before we go back to the collar bones.

  • We can define the shape of the bones a bit more by adding some more volume and giving it a better shape.

  • We want the torso and legs to be a bit more separated from each other, we can do this with the DamStandard brush.

  • From this point, we’ll start to add the last details on the front of the torso using all the various brushes from this class.

  • With the DamStandard we make some lines around each abb to make the form not so perfectly squared.

  • With the Clay brush, we’ll add some clay on the bottom of the abbs and try to make them slightly vanish since they are not bottom-heavy muscles like the other abb muscles.

  • By scrolling through the Undo History we can see the progress we’ve made so far on our blockout.