A step-by-step guide to modeling the base mesh of a low-poly game character Part 1
Learn from an industry professional and have a go at creating your own portfolio-worthy game character with this free chapter from The Swordmaster in 3ds Max and ZBrush!
In this portion of the series we are going to cover creating a base mesh model. A base mesh is the model intended for sculpting and ultimately is the beginning of what our high poly model will be. For this project, the base mesh will include organic sections such as the face and body, which will then be sculpted and used as a basis for armor design in future sections. Using this workflow is a great way to increase speed and really get your ideas into 3D quickly, worrying about overall aesthetics first and clean topology second.
Modeling the base mesh
We begin by gathering references. In this case concept art has been provided for us in the form of an action pose and a standard model sheet showing the front, side and back of our Swordmaster character. Different projects will require a different level of accuracy; once you become comfortable with your craft it is perfectly fine to model in perspective view or freestyle details. On most commercial projects, there will already be character rigs used within the game, which will require you to build your model to those guidelines. This helps on a wider scale as you can then share animations between characters with similar body types (Fig.01 - 02).
To begin, I split up the character based on the views that I will need. For me this is just going to be a rough
guide to help ensure the accuracy of proportions. When it comes to detailing, I tend to switch to a freestyle workflow. In Photoshop, select the area that includes the front view of the character. Press Ctrl + C to copy the information, open a new document and save it as a new image. Repeat the process for the side view, making sure to take note of the height and width of each image (Fig.03).
Next, open up 3ds Max and create a box by going to the Create panel and then navigating to Geometry > Standard Primitives. Click and drag in the Perspective viewport to create the box primitive. In the Width and Height rollout menus, enter the dimensions of your front view image. In my case, the image is 1686 x 1878 units (Fig.04).
The box now needs a material as a perfectly black box makes it very hard to pick out edge details. We also
need this material to begin setting up our reference images. Press M on your keyboard; this will bring up the Material Editor. You'll notice a nice collection of blank shader balls. Click on the first shader ball and rename it "Front”. This will be the material used to display our front view reference image. Move over the object, right-click and select Convert to Editable Poly from the menu that appears (Fig.05).
Click on the Diffuse button and then click on Bitmap. This will allow a 2D image to drive the basic color information within your material. Navigate to your front reference image and click OK. Select your front view box and click the Assign Material to Selection icon or, alternatively, click and drag the shader ball onto your model (Fig.06).
Create another box and give it the dimensions of your side view image in the Length and Height coordinates. To make sure that both boxes align perfectly, you can select each box and enter the sizes into the XYZ coordinates at the bottom of the screen (Fig.07).
Create a new material in the Material Editor and enter the name "Side”. This will help keep things organized as you move along in the project or if you need to change anything. Apply this material to the new object you created (Fig.08).
Next create a new box and enter Edge mode by pressing 2. Split the box down the middle by selecting a ring of edges in the XZ plane and pressing Connect in the Edit Edges panel. By simply clicking the Connect button, it will use whatever value was previously entered. By default the value is 1. By clicking the details box next to Connect, an options menu appears that allows you to adjust this value. This rule can be applied for most functions in Max (Fig.09).
Enter Face mode by pressing 4 and delete all of the faces of the box except for the left side on the XZ plane. This grid will be used as the basis for the rest of our character's face. Enter Object mode and move this new grid so that the bottom right corner roughly lines up with the mid-point between both of the character's eyes (Fig.10 - 11).
The main modeling technique I use is edge extrusion. This means that rather than taking a primitive and cutting away at it until it resembles the shape needed, I duplicate edges along paths and fill in the remaining areas. After some practice, I find that this technique allows me to quickly block out forms, requires less clean-up work and gives more control over edge flow. This style of modeling also requires you to constantly check your model from all angles. Since it is mostly used in the perspective view, it is easy to move away from the concept's proportions, so be sure to check your work often.
Begin by selecting the bottom-most edge, holding Shift and moving the edge down in the Z axis. This essentially creates a new face and you immediately begin controlling the connecting edges. Repeat this process until you reach the tip of the nose, making the faces more or less as squares for better subdividing during sculpting.
At this point I also begin working with symmetry, which can be accomplished in various ways. I prefer to instance the model, mirrored on the X axis. This doesn't require us to depend on a modifier and allows us to make duplicates of the original object that will carry changes over to the new objects. With the object selected, navigate to the top of your screen and click the Mirror icon. When the options menu appears, select Instance and the X axis. An instance means the new object will copy future changes made to the original object (Fig.12).
From here on out, we will basically be using the same technique to mark key landmarks of our base mesh. The key to a good base mesh is evenly distributed polygons, meaning that all of the faces are roughly square and that no area is denser than the others. However, if the model is broken into different sections (e.g., a head and a body) the head could be denser than the body depending on what you need. Another important thing to keep in mind is that ZBrush does not play kindly with triangles, so the model should be mostly made of quads with triangles reserved for areas that won't need sculpting attention.
Continue to extrude edges to mark the extreme angles of the character's face, outlining the brow, bridge of the nose and the chin. Try not to go into too much detail when creating the base mesh as a large portion of the high resolution work will be done in ZBrush. Also, the more dense a mesh is the more complicated it becomes to work with as there are more vertices to manage (Fig.13).
Next, using the front reference image as a guide, begin marking the character's cheekbones by connecting the outer brow to the top corner of the lip. This mimics the muscles underneath the skin that allow our faces to squash and stretch during extreme poses. Begin to define the shape of the lips and give depth to the eye sockets by defining the brow more (Fig.14).
Now you can begin to fill out the face by defining the eye sockets more by extruding edges inward to give them some depth. You can also fill in the lips by connecting the top lip edges and bottom lip edges and filling in the nose. Don't bother detailing the nostrils as you can add these details in ZBrush (Fig.15).
With the brow and cheeks defined, begin filling in the eye sockets by grabbing the boundary of edges and extruding them inwards, connecting the top and bottom edges together with a connecting edge dividing them. This will help place our eyes when we sculpt, and by using simple geometry it allows us to experiment with different eye shapes and details without everything becoming too messy (Fig.16).
If you find these edges too sharp and you would like to soften the area, select the vertices in that area and in the Modify panel, scroll to Relax. This will add a Relax modifier that averages out the position of the vertices without adding any geometry, which is good for smoothing out tight areas like eyes and mouth corners. Once this modifier is added you can increase the intensity, with 0 being your original model and 100 being fully relaxed, and the amount of iterations, which more or less repeats the function. So a Relax modifier of 0.5 with 2 iterations is the same as a modifier with the strength of 1 with 1 iteration. Once you are done with the modifier, right-click over it in the stack and click Collapse To. This will bake any changes down to your model and allow you to continue modeling (Fig.17).
The last step you need to take is to fill out the character's cheeks and jaw, connecting the edges of the chin to the ring of edges creating the forehead. For this character you just need to create the face as the rest of the head will be covered by armor. However, using this same technique you can easily see how the shape of the cranium could be completed (Fig.18).
With half of the face complete, you need to connect both sides. In the Modify panel, right-click Editable Poly and select Make Unique. This causes the object to no longer affect its instance. It also allows us to attach one model to the other (Fig.19).
With either side of the model selected, scroll down in the modifier and select Attach. This will change your cursor to a crosshair type object, which means that Attach mode is active. This means any object that you select will become part of your original model. Select the other side of your character's head and right-click to end the operation (Fig.20).
After you attach the halves of the face together, there will still be a seam running down the middle. To fix this select the boundary edges, and click the Weld action in the Modify panel. If the edges do not weld together right away, you can open the options menu and raise the Tolerance amount. This will cause edges or vertices within that distance to become fused together (Fig.21).
With the head complete, it is time to move on to the character's body. Here is where you can start to stray from the model sheet and I believe this process comes down to personal preference and what your project requires. A rig pose may be predefined, which restricts you to modeling your character a certain way, so you may need to model to a rig rather than rig to a model. Modeling a character in the standard T pose – that is with the character's arms raised to be parallel with the floor – can cause stress on the mesh and end up giving your character a box torso when the arms are lowered, but it is also incredibly easy to work with as you are dealing with straight edges. Modeling at a perfect 45 degree angle can be easier to rig, but can be a touch awkward to look at. When not dealing with one of these standardized rigs, I like to relax the arms a bit from a 45 degree pose, basically dropping the hands inward a touch with the back of the hands facing outwards. To me, this leaves the character looking natural and takes away any stiffness from the usual poses.
With the granted freedom of a personal project, I will sometimes change my character's base pose as I work.
Essentially, I block out a more standard pose – like the relaxed 45 degree pose – and go from there, maybe bending the spine more, changing the character's posture to reflect attitude, bending the arms, etc. Really, if there are no limits, it all comes down to what works best for you and what is the easiest way to sculpt (Fig.22).
Create a box for the neck using the same technique, extruding edges from one edge to follow the length of the neck from the chin to clavicle and working from there horizontally to create the rough shape of the neck. To mark the area, rough out the general length of the trapezius muscle; this helps give an idea of where the deltoids will begin.
The general idea here is that you will be creating a character's under-armor, which will then be sculpted as a basis for the real armor pieces and organic sections in between (Fig.23).
Extrude edges from the base of the clavicle all the way down to the waistline, adding a slight indication of where the chest will protrude. Using the side reference shot as a guide, begin to block in a loop for the entire waist. This quickly helps to show how wide the character will be and will also act as an anchor for connecting edges to the chest and legs (Fig.24).
Next begin widening out the chest and stomach. For the most part, the stomach should be practically cylindrical with loops running horizontally the whole way around. The edges making up the bottom of the pectoral muscles, however, will carry through into the bottom of the deltoids and around the back into the spine. This helps define the armpit area and the mass for the shoulders that is created when the arms are raised or lowered (Fig.25).
From here define the mass of the deltoids. I like to create a loop that circles the upper portion and loops around the arm. This comes mainly from an animation standpoint that has carried over to my base model creation technique, but it also helps to define the valley where the clavicle, trap and deltoid meet (Fig.26).
To complete the body, the rest of the work is really just filling out these major points that we have defined with clean topology, keeping the mesh equally dense and composed of four-sided polygons. Much like the shoulders you should define the hips with a loop that will circle the legs. I also like to continue the edge flow of the shoulders across the entire back (Fig.27).
That concludes part one. Part two continues next week...