CAP 201a - Computer Animation I

Lesson 4 - Chapter 7, Character Poly Modeling (Part 1)

Objectives:

Chapter 7 reinforces the modeling skills introduced in chapter 3 by creating a character model. Objectives important to this lesson:

  1. Reference images
  2. Creating a standard primitive
  3. Modifying a primitive into a model
Concepts:

Modeling often starts with a primitive form that is roughly the size and shape of a major component of the model you want to make. You may recall an exercise from CAP 101 in which you were told to sketch objects in terms of the primitive forms that might be used to construct them. Yes, there was a reason for that assignment. We will use that idea in this chapter.

The authors begin the chapter with some observations about making either a high polygon count model or a low polygon count model for a character. In many cases, you may need to make both kinds of model for major characters in your production, because you need them for different kinds of scenes or shots. In a game, for example, you want a low polygon model for long and medium shots when the system has other things to do, like calculate and resolve combat. You want a high polygon model when you see a character in close up shots that require high facial detail.

As this model progresses, remember that it is only a low polygon count model. You may not believe this after a while, but it is true.

Project: the Soldier model 

This project includes a series of exercises to create a character model of a soldier. The text does not say so, but you should begin as before by copying the project file from your download or from the class resource drive to your working area, and setting 3DS Max to use that as the root folder for this project. The folder for this project is called Soldier.


Project Exercise 1: Reference planes 

The exercise starts by telling you to open a new file.

  1. In your new file, start in the Front viewport. The text tells you to create a plane. I would recommend using the Keyboard entry method. Of course, you can't do that until you get the dimensions that are in the next step.
  2. The text gives you parameters for the length and width of your plane. This plane will hold a reference sketch for your character. If the authors had not done so already, you would need to calculate appropriate dimensions for the plane based on properties of the image to be displayed on it.
    Question 1: Three parts: What properties of the image to be displayed would you need to know? What properties of the plane do each of those properties correspond to? How can you determine what the properties of the image are?
  3. The text says to rename a box. It means "rename the plane you just made". Use the name given in the text.
  4. The text says to go to the Modify panel. You should have already been there to carry out step 3. On the Modify panel, set the plane's length segments and width segments to 1.
    Select the Move tool, but don't drag the plane. Use the transform type-ins (located at the bottom of the workspace) as instructed to move the plane to an exact location. After you type each value, press the enter key to lock it in, and to see the plane move a bit.
  5. The text directs you to use the keyboard command for Zoom Extents All (Z). You could also have clicked the appropriate button in the lower right area of the workspace.
    You are about to use the Rotate tool.
    1. Turn on the Angle Snap toggle so you can rotate in 5 degree increments cleanly.
    2. Click the Rotate tool, and if the plane is not selected, select it.
    3. Hold down a shift-key and rotate the plane as instructed.
      Question 2: What is the effect of holding down a shift key while rotating or moving an object?
  6. Set the Clone operation to Copy, name the new object, and complete the operation as instructed.
  7. Click the Move tool, and use the transform type-in boxes again to move the new object as specified. When I did this, the new plane did not go the correct location. Examine the perspective view at the bottom of page 143, and adjust the position of the new plane to resemble this layout.

Project Exercise 2: Adding the Materials 

The exercise is on page 143.

  1. Switch the Left viewport to be a Right viewport. You can use the method in the text, or use the drop down box for the viewport to change its view. Change the shading for this viewport to Smooth + Highlights, if it is available, or to Realistic or Shaded if it is not.
  2. Open Windows Explorer, and find the folder indicated in the text that has the images you will need in it. Drag the named file from Windows Explorer to yours workspace, and drop it on the first plane you made. It is a good idea to drop it on the plane in the Front viewport, because this will apply the image to the correct side of the plane.
  3. Return to Windows Explorer and drag the second image to the second plane, this time dropping it on the plane in the Right viewport.
    A side effect of this operation that I noticed at this point was that the two planes could no longer be seen from any side except the side that the image was placed on.
  4. Save your work at this point. It should go into the Scenes folder under the root you set for the project.

Project Exercise 3: Forming the Torso

The exercise starts on page 144. Modeling begins again here. You should continue with the file you have been making so far. Note the planning section on page 144 that describes what you will be doing in the next several pages. This is a good feature the authors have added, explaining their intentions before starting a series of steps.


By the way, bring a candy bar. This is a long tutorial.

  1. Configure all viewports to show Smooth + Highlights, and Edged Faces (F3 and F4).
  2. Create the box with the properties in the text. Move the box so that it lines up with the reference images. If you have the same experience I had, you will be wondering at this point how it got so small. If your box is tiny, use the scale tool to increase its size. Why not just add to its height and so on? The proportions are also important, so the scale tool is the better choice. Use the keyboard command to make the box semi-transparent: Alt-X. (Remember this command. You may want to undo it later, as I did several steps down the line.)
    Name the box as instructed.
    This box will become the left side of the torso of the soldier model. The box has a left side and a right side at this time, but its right side will become the center line of the model when the box is mirrored. The left side of the box will continue to be the left side of the model's torso.
  3. If all the properties are assigned, convert the box to an Editable Poly. The properties will not be available after the conversion.
  4. Now that you have an object that has subobjects, go to the Vertex subobject mode for the box. Look at the model in the Right viewport. Move vertices to make the model line up closely with the reference image, like the large illustration on page 145.
  5. On the Graphite panel, Edit tab, enable the Swift Loop tool.
    Change to Edge subobject mode. Examine the top illustration on page 146.
    This is a little tricky, since there are no measurements given. Add the two loops shown in yellow to the model. The loops should divide each polygon on the front, back, top, and bottom of the object into three roughly equal polygons. If you click then decide it is wrong, use the undo function. It seems to work properly here.
  6. Continue using the Swift Loop tool as instructed on page 146 to make the new series of edges shown in the illustration at the bottom of the page. Note that the edges do not need to go around the side that will become the center of the model.
  7. This step begins with an overview: Torsos do not have square edges. The transition from front to side is generally a curve. You want to round off the shape of the torso a bit by moving some edges toward the back of the model.
    1. Start in Edge subobject mode.
    2. Click one vertical edge where the front and left side of the torso meet.
    3. On the Graphite ribbon, find the Modify Selection tab, and click Loop.
    4. Use the Move tool to move the loop toward the back of the model.
      Repeat the process with the next vertical line of edges, making sure not to move these as far back as the first line of edges.
  8. Go to Vertex subobject mode.
    1. Select the vertex shown in red at the top of page 148. Why? It is approximately at the right location for the model's left shoulder joint. The location will change a bit as you go on.
    2. On the Graphite panel, Vertices tab, open the settings for Chamfer.
    3. Set the Vertex Chamfer Amount to 4.808. This setting is on the caddy, not on the tab you opened. Why that number? I will guess that the authors ran the value up and down until it looked about right, then recorded the number for us to use.
    4. Click the Check Mark button (OK).
  9. Go to Polygon subobject mode. You should have a new polygon that replaced the vertex selected in step 8. Select and delete it.
  10. Change to Edge subobject mode. Select all four edges of the hole you just made, and the four upper, outer, edges that are also marked in red in the image at the bottom of page 148. Why? We are going to subdivide all of those edges in the next step. We are gradually adding more polygons and more complexity to the model. Remember, more polygons mean smoother curves.
  11. This is a new method. On the Graphite panel, Modify Selection tab, click Ring. A ring is a set of edges that don't connect, and the ring runs at ninety degrees to a loop. This action will select two sets of rings.

    Consider this example, so you'll get the concept in the next command.
    In the image below, I have selected a loop of edges that run around an Editable Poly that has lots of edges. The selected loop is shown in red.
    loop of edges

    In the next image, I started with the same edge I picked above, but I have expanded it to a ring. The ring is again shown in red. Note that all the edges are parallel in this case, and none connect to each other.
    ring of edges
    In the exercise, you selected two rings of edges to be able to bisect all of them.

    The next command is on the Graphite panel, Loops tab, Flow Connect. Why the Loops tab? We want to run a loop through the rings we just selected. The effect should resemble the image on page 149.
  12. The text continues to be a little cryptic about which edges to select. Look at the first image on page 150 to see the edges they mean by "the two horizontal edges under the arm hole". (Good thing there is a picture. I see about fourteen edges that meet their description.) Once you tell the program to ring those edges, you will see that it did not matter which pair you chose. Your model should resemble the second image on page 150 at this point.
  13. The text advises us that the new edge loops need to connect to the arm hole. We can use the Cut tool to do this. Graphite, Edit tab, Cut tool. Click the tool to engage or disengage it. Follow the instructions and use the picture on page 150 to make sure you cut where you are supposed to cut. Note also that the cut tool assumes you will continue cutting, from the last vertex to yet another, unless you follow the instruction to end a cut: right-click.
  14. Step 14 is pretty straightforward. Carry it out to cap the hole in the model with an NGon (a polygon with many sides).
  15. Step 15 uses the GeoPoly tool to convert our new NGon into a regular NGon: all sides are the same length, and all angles are the same.
  16. Step 16 says to delete the new cap. Why did we need it? To make the shape of the hole regular. This step also says to delete the (single?) polygons at the top and bottom of the model. I don't know where our authors have been, but on my screen there are multiple polygons on both the top and bottom surfaces of the model. If you have multiple polygons in those locations, go ahead and delete all of them. We appear to need gaping holes at the top and bottom of the mesh at this point. (You recall that "mesh" is a generic term that includes Editable Poly objects, right?)
  17. Ignore Backfacing Check BoxThe text says to go to the Graphite panel, Polygon Modeling tab (This is the first tab on the left side of the ribbon), and turn on the Ignore Backfacing feature. Of course, it has no label, and the picture in the text is too small to recognize. Is there some reason we should not just look to the right, on the Modify panel, where there is a check box beside the words Ignore Backfacing? A check box which, by its very nature, tells us immediately whether it is turned on or off? We need only look at it to know. Sometimes, children, the new way to do something is no improvement over the old way to do it. (I will be back in a moment. I need to go hit something with an axe.)
    Now, we are directed to delete the polygons that are on the side of the torso that is really the center line of the figure. See the second image on page 152 to get the idea visually.
    Do this, then save incrementally again.
  18. Step 18 is a bit different in this exercise: the authors assume you have learned something. They tell you to select a loop and move it. They do not specify how to do it.
    Question 3: Since you are in Polygon subobject mode at this time, what should you do to select a loop and move it? Describe three steps that are necessary.

    Continue moving loops of edges as indicated in the text. Note the image at the top of page 153. In that image the authors have selected a loop that runs up the front of the model and down the back. To select this loop, you may have to select one edge in front, and one in back, before clicking the Loop tool.

    If the Loop tool does not make a loop that you expect it to, there may be a problem with extra vertices in the model. If this is so, you can correct it by using the Weld or Target Weld tools. Weld relocates two selected vertices to a new location halfway between them, becoming one vertex. Target Weld requires you to select a first vertex, which is then relocated to the position of a second vertex, leaving only one.

    It may help to review before something gets confusing. The Loop tool selects edges that are arranged in a loop. The Swift Loop tool creates a new loop of edges. Loop can be used as a verb (when you use a tool) and as a noun (what the tool selects or creates).


    Examine the images on pages 152 and 153, and move edge loops as necessary to approach this shape. I also recommend moving a few vertices, as needed, to adjust the breast and collar plate. (Plate? The soldier will eventually be given an armor texture.) In this section, and others, it is also helpful to toggle the transparency of the model on and off. Sometimes, it is better to see the polygons.
  19. The authors suggest moving some vertices around the arm hole to add more rounding to the model. At this point, your model may be different enough from the book version that you need to consider this on its own. Move some vertices if needed.
  20. If you have not already done so, move the edge loop indicated on page 154 to the best position.
    In fact, use a viewcube to rotate the model, looking for vertices and edges that are in "awkward" places. If you find some, move them as needed.
    When you are satisfied with the model at this stage, save incrementally again.

Project Exercise 4: Creating the Arms

  1. Select the Border of the arm hole using the Border subobject mode. In the Front viewport, shift-drag the border on the x axis until it extends as far as the wrist of the reference image.
  2. Use the Swift Loop tool to add three edge loops to the new arm. To place them evenly spaced, as the text says, it is easiest to put one in the middle of arm first, then another in the middle of each new section, resulting in four even quarters along the length of the arm.
  3. The text says to switch to Vertex mode and to move the new vertices on the arm to match the reference art. It will be easier this way:
    1. Continue in the Front viewport. Turn off Ignore Backfacing, so you can select vertices on both sides of the arm at once.
    2. Marquee select one new loop of vertices. Use the Move tool move the loop to the right place on the y axis.
    3. Repeat step b with all arm vertex loops except the original arm hole.
    4. Scale the loop of vertices at the end of the wrist to the right size. Scale the other loops, one at a time, so they fit the reference art better.
  4. Change to Edge mode. Look at the two edge loops shown on page 155. Select and move the lower one first, or you will not be able to find it. Select and move the upper one as well, but take care to select the matching half of the loop on the back of the model so you can move it the same amount in back as in front. (The back half may not be selected when you click Loop.)
    At this point you may want to switch to Vertex mode, and move some of the vertices in the armpit area individually.
  5. If your armpit has one more loop of edges under it, as shown on page 156, you should follow the instruction in step 5 to move the loop of edges as shown down enough to remove the cave that has formed under the arm in that illustration.
  6. The text says to use the Front viewport to select another edge. What it does not say is that it wants you to select the middle vertical edge on the arm, not the middle horizontal edge. Loop the edge, then apply the Chamfer settings given to add two parallel edges new the selected loop of edges.
  7. The text is a bit unclear again. You want to select another edge that you created with the Swift Loop tool. Loop the edge, then use the (different) Chamfer Settings given in this step on the selected loop. Repeat this step with the last loop of edges you created on the arm. Each of the selected loops in this step will convert to a pair of loops.
  8. This one is easier than it will feel in a minute. Go to Border subobject mode. Select the border at the end of the wrist. Select the Scale tool. Hold down a shift key, and scale down only on the y and z axes, How? Move your mouse pointer over the Scale gizmo until only the bar connecting the y and z axes is lit up in yellow. Then drag to scale down until all vertices meet in the center of the wrist opening. (You may have to move the mouse, lift it from the table, and move some more, but it will get there.
  9. Go to Vertex mode. Marquee select the multiple vertices that may now exist at the center of the "wrist opening". (It isn't very open any more, is it?) On the Graphite panel, find the Vertices tab, and open the Weld Settings caddy. Set a Weld Threshold of 3.39 as instructed, and click the Check Mark button (OK). This should actually close any remaining gap at the end of the wrist. If the entire end of the wrist becomes one vertex, your threshold value was too big. Sometimes you have to do it a time to two to get the right value.
    Save incrementally, then show me your work before you close the incision and wake the patient.

Project Exercise 5: Creating the Legs

  1. Step one tells you to select the loop of edges that run around the bottom of the torso. As a bit of unintentional comedy, the authors suggest that you can do this by selecting one of the edges, then clicking the Loop button on the Modify Selection tab of the Graphite ribbon. Really? And what do they suppose we have been doing for the last ten pages?
    Use the Front viewport. Hold down a shift key, and use the Move tool to drag the loop of edges from the waist down to the groin, as shown on page 158.
  2. Cutting the EdgeThe text tells us to use the Cut tool next, which is on the Graphite ribbon, Edit tab. The text is not clear about what to cut. Look at the first picture on page 159. There is a red line on it and a yellow line. The yellow line is irrelevant: ignore it. Continuing in the Front viewport, the red line represents the new edge to add to the polygon at the bottom left of the model at this point.

    In the image on the right, I have turned off transparency, and set my model to a shade of green. I am using the Cut tool in this picture, and have just dragged from the specified position on the lower edge to the vertex that will be the end point of the cut. Note, clicking the cut tool creates a new vertex, or links it to an existing one. Right-click the model to stop using the Cut tool. If you do not, the tool will assume you want to cut more edges.

    There will be a matching polygon on the back side of the torso. Make the same cut at the same angle on it. If you change to a Back view to do the cut, make sure you are cutting in the right direction.
    Turn off the Cut tool when you are done by clicking its button again. (This is not the same thing as right-clicking the model. It has to be turned off at the button.)

  3. Go to Vertex subobject mode. Select the two vertices indicated in the text, and switch to the Move tool. Use the appropriate arrow on the Move gizmo to move the vertices vertically only. In the image below, I have spun the model around in the Front viewport. I selected both vertices, then moved them up. In the image, I have put red ellipses around the vertices to call your attention to them. Note the new edges I added in the last step in the image below. They rise at the same angle in their respective polygons. Check yours, and if they are not right, Undo as needed, make corrections, and catch up again before continuing.
    Move vertices vertically

  4. Go to Edge mode. Select both of the edges that appear just below the two indicated vertices in the image above. On the Graphite ribbon, Edges tab, click the settings for Bridge. Change the Segments setting to 4, then click the Check Mark button. The result should resemble the first picture on page 160.
  5. Change to Border mode. Select the border at the bottom of the model. Use the Right view of the scene or you can't follow the next instruction.
    Use the Move tool and shift-drag the border down to the level of the figure's knee. (In step 8, it is revealed that we should be at the top of the knee cap.)
  6. On the last page, the text said you would cap the border. That happens in this step.
    If the border is not selected, do that first. Next, go to the Graphite ribbon, Geometry (All) tab, and click the Cap Poly button.
    Go to Polygon mode. Select the new polygon (the cap). On the Graphite ribbon, Polygons tab, click the GeoPoly button to modify the shape of the cap.
  7. The polygon should still be selected. If it is not, select it.
    Use the Scale tool to shape the polygon into an oval like the one in the text. You can size it a bit at this stage as well.
    When the polygon is sized to match the reference art, delete it, so you can work with the border again. (You will work with it soon.)
  8. You may have shaped the leg to match the knee in the last step. If not, you have another chance here. Go to Vertex mode. It would be best to use both the Front and Right views in this step. Move vertices as needed to make the thigh section of the leg resemble the reference art. Try moving small groups of vertices at once to maintain the space between members of a group.
    This would be a good time to take a look at the torso as a whole. Examine the torso from top to bottom. Look in the Front and Right views. Move groups of vertices to sculpt the form of the torso to match the reference art more closely.

    Before moving vertices After moving vertices

  9. In step 9, the text says to examine the four segments of the bridge you made in step 4. At this point the internal edges of the bridge have probably moved. The text wants you to select and move them so they are evenly spaced across the length of the bridge.

    Bridge before moving internal edges
    Image above is the bridge at the end of step 8
    Bridge after moving internal edges
    Image above is the bridge at the end of step 9. Vertical edges have been moved horizontally.

  10. Go to Border mode. Select the border that is now at the model's knee. Use the Move tool to shift-drag the border down as far as the ankle in the reference art. Note that it will not look like the image on page161. The method creates a straight tube. The image shows it after vertex movement that will take place soon.
  11. Use the Swift Loop tool to add new horizontal loops to the leg, as indicated on page 161. The text says to add three new loops of edges, but I found I had better control by adding four loops. Once the loops are in place, the text says to move vertices in the Right and Front viewports to conform with the reference art.

    I would make two suggestions here
    . Please follow them.

    First
    , instead of moving single vertices in those views, move small horizontal groups. In the image on the right I have selected and moved three vertices at once. Do a marquee selection for the vertices, move them to match the reference line, then marquee select the remaining vertices on the same loop and adjust them as well. (Test your intuition: should Ignore Backfacing be turned on or off? Did you think about it before you moved vertices?)

    Second
    , you will probably mess up somewhere, and have some edges that look like creases in the leg. You can correct this by selecting all the edges in one crease, then find and click the Set Flow button on the Graphite ribbon's Loops tab. (You have to be in Edge mode to see it, but you have to be there to select the edges, too, so you should be in that mode already.) This will generally set the selected edges to match the shape established by the edges that surround them. A useful tool to know about.
  12. Go to Border mode, and select the border at the end of the ankle. The text says to shift-drag the Scale tool on the z and y axes. If this is correct in your workspace do it, however, I found that the correct axes for my model were x and y. Whichever is right, shift-drag the Scale tool to close the gap on the ankle.
    As you did for the wrist, go to Vertex mode, select the vertices at the center of the ankle closure and weld them together. The threshold you used last should still be correct. We will use another one later in the project.
    Once again, save incrementally, and show me the work at this stage.

Project Exercise 6: Fixing the Body

This exercise ends the chapter. Continue with the model you made in the last exercise.

  1. Edges above the beginning of the legThe exercise begins on page 162. The text says to select the ring of vertical edges at the waist. I was not sure what the authors meant by "at the waist", and you may wonder as well. Examine the top image on page 163. They mean the edges just above the beginning of the leg.

    In the image on the right, I followed the authors' procedure:
    1. Select one of the vertical edges just above the leg.
    2. Click the Ring button on the Modify Selection tab on the Graphite ribbon.

  2. Right click the viewport you are using and the Quad menu appears. Find Collapse in the upper left section and click it. The vertical edges go away and the horizontal loops above and below them are merged.
  3. You will need to change the camera angle several times in this step. The edges of the bridge structure are not pointing in the right direction yet.
    Rotate around the model until you see a view like the second picture on page 163. The text says to move edges or vertices to get the shape shown in that picture. I found it easier to do it by moving vertices. Try that method.
  4. This step eludes me. I have no idea what they mean here. They did not help by failing to offer a method to correct whatever problem they are looking for.
    Save incrementally again, and show me the work at this stage.