Project 2: Head Modeling
In this project we will create a subdivision surface head using polygon tools. You will be modeling a head from given reference photography or your own head (you will need to take your own reference in this case). For this project we will be working in the Polygons menu set. Create a new Maya file to begin.
You should be familiar with the polygon tools and so the instructions for this assignment will be less explicit than previous projects, however new concepts will be explained. The tutorial below gives you a general idea for how to model a human head such as edge loop placement, but your model will vary in the specifics. You will want to make your head match your reference as closely as possible. Be sure to review the Image Plane prerequisite exercise so you can properly set up your reference images in Maya. Also be sure to go through the Subdivision Modeling exercise as there are important concepts to understand.
Before diving into modeling your head, it is a good idea to get a sense of how a human face is put together. Since we are so naturally attuned to human faces, it can be both daunting and challenging to try to model something that our brains can interpret so flawlessly. We can immediately pick up on little changes that can make or break the believability of your model. Since there is plenty of history to go off of in the arts when it comes to recreating the human figure, it's a good idea to look back and pull from what has already been established. When taking away all the technical and computational aspects, modeling essentially becomes sculpture. And since sculpting is such an old practice, we shall look at what it teaches us.
There are three key aspects to modeling/sculpture that should be taken into account. The first and most important is the notion of gesture. Gesture is defined by the overall arcs and curves that are built into your model as well as the gestural rhythm created by the peaks and valleys in the silhouette of a figure. The images below demonstrate both concepts. In the first image, we see Bernini's David and his impeccable use of gestural lines throughout his model. Notice how they are not straight, but nice curves that somewhat oppose each other. Since you are just modeling a head it may not seem directly relevant, but the next image shows a concept of gesture in the rhythms that are created in the silhouette of the figure. Always pay attention to these concepts in modeling as this is the first thing the eye sees. Our eyes and brains reads this quickly, and much of the character and emotive expression is born out of these concepts. Always check your silhouette as your work. You can do this by pressing 7 on your keyboard. This brings you to lit mode, but since there are no lights in the scene (besides the defaults) it will be black letting you concentrate on the rhythm of your model. Exit lit mode by switching to shaded mode by hitting 5.
The second aspect is what we call form. Form is the inner detail and features of your model. We can see form because of how light plays on a model. A good way to see how this works is to think of a complex organic form like the human face in terms of planes and how plane breaks affect the light hitting the surface. Below are images of a human face broken down into its planar structures. Observe how the light changes where the planes break. Also, the second image points out major plane breaks in the human face that should be more or less universal. Although the image is that of an idealized male form, these highlighted breaks are usually always seen in the human face, but how they are shaped is unique to the face your are modeling. Always look at your reference to see how these apply to your face.
The final key concept of modeling is proportion. Proportion is the least important because it can be exaggerated and changed for stylization purposes. However, even when stylizing, proportions can drastically change the character presented within your model. Since you are trying to model a realistic face, you will want to adhere to realistic human proportions. Use your reference to guide you for attaining the appropriate proportions. In one idealized model for anatomically correct proportions, the face is said to start at the hair line. From there you can divide into even thirds to the bottom of the chin. The eyebrow ridge sits at about a third of the way down from the hairline, the end of the nose sits sits at around two thirds of the way down. Between the bottom of the nose and the bottom of the chin, you can once again divide into even thirds. Down from the first third rests the middle of the lips and down one more third, the chin begins its form. Again, these are for an idealized figure and are merely meant as guide. Use your reference to truly determine the right proportions for your model. The images below visualize the above concept.
NOTE: The above images do not reflect the expected output from following the tutorial. Some of the images were made outside of Maya, but were included to help you understand more about the modeling process. Below, the tutorial within Maya begins, but always keep the above concepts in mind while working. Look at the Hotkeys and Tools above to help you create your head. You can learn more about these tools by reading the Maya Documentation which can be found by hitting F1. Also, be sure you are using reference images of your own head when attempting the tutorial below.
Another great resource to keep in mind when creating a head model is hippydrome.com. This website was created by a facial articulation expert to help modelers create the optimal face model, capable of performing believable and expressive motion. Although the model you create for this exercise will not be animated, good topology is important to keep in mind for future models in the production, which will be rigged and animated. We will be creating a simplified version of the ideal hippydrome model.
Once you've set up your scene with your reference images, you're ready to start building your model.
Remember to SAVE OFTEN, and save iterations as you progress. This will save you a lot of time and effort if Maya crashes on you.
If a tool is not working properly, it might be helpful to freeze transformation (Modify > Freeze Transformations) and delete history (Edit > Delete By Type > History). It might also be helpful to do this often if you work on a Student Version of Maya.
- Using the Create Polygon Tool, draw a outline of your character in the Side camera view (Mesh Tools → Create Polygon). Use as many points as you think would be necessary to create the outline. Press enter to complete the tool.
- Extrude (shift right click on polygon, select Extrude Edge) the outer edge and then delete the extraneous polygons.
- Switch to front view, and outline the eye. One of the best ways to do this is to use the Quad Draw tool in the Modeling Toolkit(
). The Modeling Toolkit can be found in the upper right corner of the Maya window next to the Channel Box and Attribute Editor:
Draw two dots in each corner of the eye, then six more above and below the eye, for a total of 14 vertices. (You must select your existing mesh before the tool will let you start drawing verts.) The vertices along the top and bottom of the eye should line up vertically with each other. Then draw another loop of vertices surrounding those 14. It should look something like this:
To create faces from these vertices, shift+left click between them, and the tool will create quads for you.
NOTE: The eye loops need to line up with each other vertically on the upper and lower eyelid. This is a good convention to follow because it makes rigging eyelids much easier.
After this is done, make sure to shape the loop you created a little keeping the angles of the human face in mind. You will also want to switch to either side view or perspective view and line up this shape with the location of the eye on the face. Once it is in approximately the right position, you can begin extruding the outer edge of the eye to connect it to the other part of the model. Make sure that you are creating edge loops that encircle the eye. There should be at least 3. Shape these a little as you go as well, so you don't end up with a bunch of flat loops.
We meed to make sure that the new eye loops are combined with the other mesh. It should already be combined, but if it isn't, follow these steps to combine the two pieces. Make sure you are in object mode, select both polygons, and shift+right click, and select Combine.
To connect vertices or edges, we can use the Target Weld tool, also in the Modeling Toolkit. Click and hold the first edge or vertex you want to connect, and then drag to the second and release.
NOTE: Remember that to exit any tool in the Modeling Toolkit, you may have to press "q" twice.
Make sure you are shaping the mesh as you proceed, otherwise you will end up with a big shapeless blob that is much harder to sculpt.IMPORTANT SCULPTING TOOLS
There are two tools that were introduced in the previous assignment. They will make shaping and sculpting your model much easier as you progress.
- Soft Select → Press "b" to toggle on soft select in the move tool. This will allow you to move big areas of mesh at once. Hold "b" and drag to adjust the size of the tool.
- Sculpt Tool
This tool can be found under the Mesh Tools menu. The above marking menu is accessed by Shift Right-Clicking with the Sculpt Tool active. There are lots of different types of tools for you to choose from within the sculpt tool that allow you to do certain things. Let's outline a few:
Sculpt will allow you to pull out the mesh in various directions (towards the camera, towards an axis, towards the direction of the mesh's normals, etc.)
Knife allows you to push in the surface of the mesh.
Relax is one of the most useful, as it averages the distance between edges and vertices, and cleans up messy geometry. Use relax every so often to keep your mesh evenly spaced so it is easier to work with.
Just like Soft select, you can use "b" to adjust the size of the brush. The default Strength of these tools is usually way too high, so if you're finding that your mesh is doing crazy things when you try to use a tool, try decreasing its strength.
- Begin forming the cheek and nose by extruding, shaping as you go.
- Build the mouth as a series of loops. Reference the hippydrome image again and notice how the mouth is created by a series of loops, but is also connected to the loops coming down from the nose. This is an important feature and should be included. Start by grabbing the edges on your face silhouette geometry and extruding them to the side. Scale them vertically as you go to match the lip shape. For this tutorial, we will do 3 extrusions, you may choose to do more if you feel it necessary.
- In order to join the mouth corners together, pull out the vertices that correspond to the same edge loop along the top and bottom lip, then merge them together. Do this for all of your lip loops.
- Now we're going to create the poles on the edge of the mouth. Poles are intersections of geometry where more or less than four faces intersect. As you know, it's very easy to extrude and merge without paying attention to where poles are being created on your model. We're going to extrude the lip edge in a specific way to ensure that our pole is created.
- Make sure your nose, eye, cheek, and mouth geometry is joined correctly before you move on. These intersections are designed to create optimal facial articulation when the model is rigged.
- Once you have the cheek and chin filled in, you will have something like a grid.
However, all of these edge loops cannot continue down the neck. There just isn't enough room for all that geometry, and if it gets too crowded it causes problems like wrinkling when you smooth the model. So we will have to divert some edge loops under the chin, and around the back of the head.
Here we've diverted two edge loops under the chin instead of letting them run down the neck. There are many different ways to simplify geometry, and the best way really depends on your model and its purpose. But it's ALWAYS important for the model to be composed of only quads.
- Start filling in the top of the head by extruding, keeping in mind that you will have to match the number of edge loops coming up from the eyes.
As you fill in the top and back of the head, it will make it easier to see how best to connect the pieces. You may need to add or subtract edge loops along the back of the head to match the number coming back from the face.
When you're extruding to create the forehead, try to keep the edge loops coming up from the eyes and going across the forehead as straight as possible, forming a sort of forehead grid. We don't want the loops stretching to the side. This makes it much easier to create eyebrow deformation on a rigged face.
The loops from above the eyes continue up and over the head, and down the neck. Extrude down the curve of the skull, adding edge loops as needed.
Note that it is not necessary for every edge loop along the top of the head to continue all the way down the neck. In most models, this area will be covered by hair. This is one case where we make an exception to the rule that we only model with quads. **This ONLY applies to the top of the skull.** Everywhere else your edge loops must be complete.
- Extrude down the side of the head, making sure to keep edge loops consistent.
Below is a common way to join different sections of geometry on the head.
- Fill in the neck by extruding down from the side and back of the head, and from the chin. You may end up with geometry like this:
Poles here are impossible to avoid, but they do sometimes cause unwanted artifacts when you smooth the model, so it's best to make sure they occur in flat or hidden places on the model. For instance, under the jaw along the neck.
NOTE: You may also want to divert edge loops on the back of the neck if your geometry is getting too crowded. There are multiple ways to do this. Here is an example:
Make sure you are only using quads.
- Revisit the shape of your model, and make any sculpting adjustments.
- Construct the eyelids.
After you've done some sculpting, we can revisit the eyes. Right now they are relatively flat. Before we create lids, we want to shape them. You can create an eyeball and use that as a guide to shape your eye socket around.
Be sure to work from all angles as you try to match your reference image. It is very easy to work in just front and side view, and forget to work in perspective. The model should look good from all angles.
Now that we've got a better eye shape, we can construct the eyelids. To do this, just select the inner loop of edges, and extrude inwards.
If you want, you can stop here, as long as this edge intersects with the eye when smoothed.
If you want to continue, you can optionally keep extruding the eyelids inside the head to form a sort of eye socket.
- Make any necessary tweaks.
- You can add an ear for extra credit. An online tutorial on ear modeling can be found (tutorial part 1 here and part 2 here). Model it separately then add it to the head. Note that this will most likely introduce a number of triangles into the mesh. Try to hide them behind the ear if possible.
- If you have not done so previously, duplicate the head across.
Select your head geometry, and press Ctrl+D to duplicate. Now, in the Channel Box on the right side of your screen, change the new half of the geometry's Scale X to -1. Make sure your head's pivot is on the Y-axis before duplicating the head across. Now would be a good time to check the curvature of the skull. The head has very few places that are completely flat. You can use the Sculpt Tool to try to smooth out any problems. Also, make a duplicate of your first eye and position it in the empty socket.
- Combine the two halves into one piece of geometry. With both pieces of geometry selected, Shift+Right Click and select Combine. Select all the vertices down the center of the face and merge them to remove the seam. Delete your History and clean up your Outliner. Name your geometry something simple and identifiable. Smooth the model and render out a still of it, but do not turn in the Maya file with the model smoothed. Note that your model doesn't need hair.
We are going to start extruding around the eye socket so that we get the poles we want. Follow the below extrusions to create an optimal topology layout.
At this point, we're going to merge everything together. You should end up with something like the image below. As you can see, we have intersections of 5 quads exactly where we want them around the eye.
Now that we've got what we need around the eye, start filling in the nose by extrusion.
We are going to extrude and merge the mesh so that the edge flows from the top of the nose, back down underneath the nose.
The image below highlights the edge flow we've created. Now the faces from the top of the nose curve and flow underneath.
Fill in the hole we've created by extruding and merging.
It's important to continue the edge loops from the eyes down into the nose. To get a good idea of how the loops on the face should be connecting to each other, hippydrome.com is a good reference. Though our model will not be as complicated, the paths are clearly indicated.
To create nostrils, select faces on the underside of the nose geometry and extrude them inwards. First scale it down, then push it up into the nose. Do this several times.
You may need to adjust the number of edge loops that you have above the upper lip and below the lower so that the numbers match.
Now, when you shift and double-click the faces around your lips, you will see concentric lip loops.
Make sure to merge the center corner vertices. It may be hard to see, hitting '3 for smooth preview can help make it more visible.
Extrude the following edge out sideways:
Extrude the top edge of the face you just created upwards:
Then merge the following two vertices together. Notice you've just created an intersection of 5 faces, or a pole, right where we want it to be on the corner of the lip.
Now do the same thing on the corresponding edge on the bottom lip, to create the same pole below. Now that your poles are in place, you are free to connect the lip geometry with the nose by extruding and merging, and start to create a cheek. Avoid creating any extra poles. You should end up with something like this:
Here we can see an almost completed model, but during the construction of the geometry, some if its shape got lost and it looks a little mushy, especially when smoothed. You can go back in using the sculpt tool and other tools to refine the shape before we move on. Make sure to refer back to your reference as you work, and work on your model from all angles.
You may need to make geometry tweaks as you adjust the shape.
Make sure you are toggling between smoothed mode and unsmoothed as you work to catch any wrinkling or bumps in your geometry.
NOTE: If you see an odd looking crease in your model when you smooth it, it's most likely an issue with Normals. Normals are the direction that a polygon face is pointing. If two faces are joined to each other, but are facing opposite directions, the model will crease when it's smoothed. The direction of faces can easily get flipped during the modeling process, especially when extruding and merging.
To fix this, we can tell Maya to force all the polygon faces to point the same direction. Under the Modeling menu set, go to Mesh Display → Conform. This should erase those creases.
