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Join Date: Nov 2007
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Chapter 3: Modeling the Human Head
Part 1: Techniques
There are multiple techniques to modeling the heads of human beings.
The "Form Down" technique
This technique is achieved by blocking in the base shape of the head and then using the tools to model in details. There is a good tutorial on this technique by David Maas (a.k.a. Stickman) at
http://www.the123d.com/tutorial/ligh...m-down01.shtml
This is a good technique for character works, but you have to keep Edge Loops in mind while subdivide sections of the mesh. This is the first technique most modelers learn because it is simplest. We will cover this briefly in the tutorial.
The "Build Up" technique
This technique is achieved by modeling the fine details of the head and then using the tools to merge sections into a usable mesh. This is a good technique but can be troublesome. It consumes more polygons and Edge Looping is not always good. This is the technique often promoted in Lightwave “how-to-do-it” books, but it doesn’t teach you Edge Looping.
The “Edge Loop” technique
This technique is achieved by modeling the basic facial Edge Loops, and then modeling details into each area. This is where you lay out the primary masses first: Eye Loop, Mouth Loop, Nose-to-mouth Loop, and Face Loop. It’s likely that you will tweak and change them later on, but laying them out from the start will help you get it right the first time from the start. This is the one we will be learning in this tutorial.
Part 2: Edge Looping
When modeling a humanoid face that you intend to animate, one extremely important concept you must understand is the concept of Edge Looping. Even if the face isn't going to be animated, it is still easier to get a more realistic shape if you follow the basic idea of edge loops. If the face is going to be animated, proper edge loops will make the face deformations work without distorting the mesh or causing mesh tearing.
So what is an edge loop? The technical definition of Edge Loops is "a 3-D modeling concept that allows relatively little geometry to convey relatively large amounts of spatial information in a given mesh object. This determines the “flow” of geometry over a surface, and usually has an influence over the placement of surface detail and direction of the object’s contours."
The basic concept is to put loops of edges and polygon chains around specific areas of the face that deform or move. The eyes and mouth are the most common locations for edge loops. This concept is carried through in nature. Muscle groups in the face form loops as well. When you open the mouth, having several concentric loops will help with the deformation of the mouth. Growing those loops to include an area around the nose and nostrils will allow for better distortion when you do smiles or sneers. The poly flow should go from just over the nostrils down to the corners of the mouth.
As I pointed out before Edge Loops are basically designed to follow the flow of the muscles of your face so that the geometry of the mesh will deform in a way that us similar to a real human face.
When starting your Edge Loops, you should identify the primary areas of importance FIRST.
There are loops starting around the following locations
· EYES – This Loop is important for getting correct deformation when the eyes open and close.
· MOUTH –This loop is very important in getting proper deformations of the mouth for talking and emotions.
· NOSE–This loop is very important in getting proper deformations of the nose.
· NOSE AND MOUTH –This loop is very important in getting proper deformations with emotions.
· AROUND THE ENTIRE FACE–This loop is very important in getting proper deformations of the jaw and cheeks when the mouth opens and closes.
One of the toughest areas to get Edge Loops to correctly meet is where the loops from the mouth and nose collide with the loops from the eyes. This is an example of good poly flow. He has entirely avoided triangles, but he has also lost some deformation smoothness, because the mesh is missing the nose-to-mouth Edge Loop.
Take a look at Jullia’s mesh. She has all the proper looping.
Part 3: Mesh Geometry
N-Gons & TrianglesWhen building an organic shape like a face which contains many areas which will deform or morph, it is important to control how edges meet and how polygons interact. Try not to have too many of the following:
· N-gons: (polygons with more than 4 points) This is because N-gons do not work in standard SubPatch. They also tend to render oddly.
· Triangles: 3-sided polygons will be in some areas, but the fewer you have the better. They should be placed in areas that are nearly flat or that will not be visible as they can cause mesh dimpling and smoothing errors.
· Vertices with more than 4 edges: Avoid points where more then 4 edges come together. 5 Edges coming together on single vertices will happen in some areas, but you should try to keep this area away from the primary morphing areas and Edge Loops. If you find that you've got 6 or more edges connecting at a single point, then you will need to clean up the mesh and changed the poly-flow.
· Areas where the mesh has too much Poly Density: It is good to have polygon density increase in areas where you intend to have a high level of detail or have detailed morphing, but DON’T GO OVERBOARD! Many beginners, myself included, have made this fatal mistake.
Grid Mesh vs. Areas of Detail
Grid Mesh refers to the area of your mesh with the least amount of detail. On a human head this is typically the top, sides and back of the head. On the other hand, the mesh you build for a human face should have extra detail in certain areas. These are called Areas of Detail; so remember to be MEEN (Mouth, Ears, Eyes, Nose). These areas are not only detailed but can be the toughest to model. So it is important to add detail to them, but keep that detail from interfering with your Edge Loops and poly-flow.
Mesh Stepping - From Detail to Grid
Mesh Stepping is the process of moving from a detailed area of the mesh to a les detailed are. Thereby maintaining poly-flow, and Edge Looping, but at the same time reducing the amount of triangles and extraneous polygons in the mesh. Typically this can be done by merging points and then merging adjacent polygons.
Part 4: References
Anyone who’s been around on the forum for any length of time will know that I am a reference collector. I proactively seek out new and better reference pictures for anything I’m attempting to model. In the case of a human face, I start with some sort of reference. If I want to create a generic face I will usually start with a drawing, but if I’m trying to model someone specific, I use a photo. I recommend photo references if you plan to make a mesh with accurate details.
I usually don’t layout Edge Loops in advance since I can picture the poly-flow in my head before I even start, but since this is a teaching exercise, I recommend that you get a reference image and plan out your Edge Loops ahead of time. This way you can maintain accuracy and not lose track of your Edge Loops or poly flow.
Part 5: The “Form Down” Technique
Are you ready to get started? Well here we go.
What we will start out with is creating a fairly generic human head. The great thing about a Sub-Patched head with minimal polygons is that you can save it as a base mesh from which you can build many faces (say you have a deadline where you need 100 generic people for a scene). A few tweaks with the Magnet, Bandsaw, and Drag tools, and you can have a hundred different faces from one cage. However, if you are building someone specific, you should always start from scratch.
Now what we build here will be slightly different from the tutorial created by David Maas.
First let’s load a backdrop. Mister Blockhead will do. Use this backdrop config file:
blockhead.cfg
First, create a box with these settings
Make sure the polygons are flipped so they are facing forward. Once that is done, adjust the horizontal edges so they match the following specification: One row blocking out the chin, one row blocking out the mouth, one row blocking out the nose and cheeks, one row blocking out the eye sockets, one row blocking out the forehead, and one row blocking out the top of the head.
The next step is to block out the basic facial features. Remember that you are trying to create loops around the mouth, nose, mouth and nose, eyes, and the entire face. Adjust the vertical edges so they block out these areas.
Next move the object out so the plane of the box lines up with the internal edge of the nostril.
Select the outer edge points along each vertical edge and move them back to the front edge of where the ear begins
Select the next column of points along the vertical spline and move them back to the back edge of where the eye should be.
Now select the center row of polygons. Use the Drag tool and adjust the profile so the polygons follow the basic curvature of the face.
Now select the next row of polygons outwards. Use the Drag tool and adjust the profile so the polygons follow the basic flow of the face.
Now select the outer row of vertical polygons. Use the Drag tool and adjust the profile so the polygons follow the basic flow of the face.
Now the underside of the jaw has no polygons. Use your point selection tool and select the points (four at a time) and create two polygons for the underside of the jaw.
Now select the center column of polygons. Use the Bandsaw Pro tool to cut the polygons like this:
You can now adjust the poly-flow across the forehead and bridge of the nose so that it is smoother.
Now select the row of polygons blocking in the eyes. Use the Bandsaw Pro tool to cut the polygons like this:
You can now adjust the poly-flow across the forehead and bridge of the nose so that it is smoother.
Select the polygons that make up the mouth-nose loop and adjust them to match the flow of the face.
Select the polygon blocking in the nose and use Bevel to create an extruded form. Then use the Drag tool to adjust the points like this
Now select the vertical columns of polygons that contain the eye blocks. Use Bandsaw Pro to create a cut
Now adjust the poly-flow of these polygons to better match the contours of the fast.
You will have to adjust the forehead, eye sockets, cheek bones, and jaw line.
You will also need to narrow the nose-mouth loop area. You can use the Stretch tool to do this easily.
Now select the horizontal row of polygons that contain the mouth block. Use Bandsaw Pro to create a cut
Adjust these points and give a wider area for the mouth.
Select the 6 polygons surrounding the mouth. Use Multishift to extrude them thus
Use the Drag tool to adjust the polygons into this shape.
Repeat this Multishift and Drag process to create this shape
Repeat this Multishift and Drag process to create this shape
Once that is complete, delete inset mouth polygons.
Now move up to the eye polygons. Repeat the Multishift and Drag process to create this shape
Repeat the Multishift and Drag process to create this shape
Repeat the Multishift and Drag process to create this shape
Once that is complete, delete inset eye polygons. Then press the TAB button to activate SubPatching. As you can see you have a basic face. You can continue using Bandsaw and Multishift to continue adding detail to the face, but you might also need to adjust the poly-flow. Especially where the nose loop meets the mouth loop, because the combined nose-mouth loop is not well defined.
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