CAP 201a - Computer Animation I

Lesson 7 - Chapter 10, Introduction to Materials

Objectives:

 

Chapter 10 introduces the materials, maps, and the Material Editor. Objectives important to this lesson:

  1. Materials
  2. Material Editor modes
  3. Using the Compact mode Material Editor
  4. Multi-Subobject materials
  5. Selecting polygons in different ways
  6. Named selection sets
  7. Reflection map
  8. Bump map
  9. Adding a map to a material
  10. Mapping types
  11. Tiling
Concepts:

A material is like a coating that is applied to objects in a scene. You can think of it like paint or contact paper that can cover any object you want it to cover.

A material can be a simple graphic image that defines a color, but it is often much more. A defined material can have several useful properties (like transparency, texture, and glossiness) which are discussed in the chapter.

Mapping is the activity of applying materials to objects, giving them a simulated detail that does not exist in their actual surface.

Our books often use the word texture without defining it. We might define it two ways:

  • the physical composition, appearance, and feel of a surface (real world)
  • the end result of a material (making a material seem like the real world)

Most images in games or movies, such as brick walls or pool balls, can be created with a texture map. Maps are what we add to a material in 3DS Max to give the material a specific appearance and simulated feel. There are two categories and several types of maps. The two categories are bitmaps and procedural maps. Essentially, bitmaps are any kind of raster image (these get blurry when scaled) while procedural maps are vector images that can be scaled without losing detail. We will see some of each, working with 3DS Max.

Most materials will have some common characteristics. Three of them are listed on page 202:

  • ambient color - the surface color of an object when it is exposed to indirect light
  • diffuse color - the surface color of an object when it is exposed to direct light
  • specular color - the color of reflections (highlights) on an object

Think about that for a moment. In the example on the right, the pool ball illustrates all three concepts, and more. Ignore the black and white parts of the ball for now.

  • The ambient color of the ball (where the light is not shining) is a deep red.
  • The diffuse color (where the light is shining, but the ball is not reflecting a light source) is a brighter red.
  • The specular color, in this case, is the color of the white spot at about 11 o'clock on the ball's surface, where the light source in the scene is actually being reflected by the ball. That white circle is called the specular highlight. The size of that area is determined by the material's glossiness property.
  • There is also a falloff area around the specular highlight. In that area the specular color fades into the diffuse color.

The text turns to discussing the main tool you will use to manage materials: the Material Editor. It can be used to assign and/or create materials for your scenes. As is usual, the authors give you a menu command to open the Material Editor. Most people who use 3DS Max would not use this command, however. The hotkey command to open the Material Editor is the letter M. If you were going to use a mouse, you would probably click the Material Editor button on the main toolbar. The advantage to using the menu command is that it gives you a choice between starting in Compact view or Slate view. (The same choice is available in the Material Editor button through its flyout options.)

A common configuration for the Material Editor is shown on page 203. This is now called the Compact view. If you learned to use the Material Editor in an older version of 3DS Max, this is what you learned. The Slate Material Editor in version 2012 (the current default) will seem strange. It contains features that older versions simply did not have. If you are in a hurry to use the Material Editor for a project and need it to look more like the older versions, use this method to change its appearance:

  1. Open Material Editor by clicking its button on the 3DS Max toolbar.
  2. Open the Modes menu on the Slate Material Editor screen.
  3. Select Compact mode.

You can use this method to toggle the view back to the Slate Material Editor as well, by choosing Slate Material Editor in step 3.

In the exercises in chapter 10, the text uses the Compact Material Editor to show you the functions of that mode. This is useful, because you will not always have access to a newer installation of 3DS Max, and you should know how the simpler version works.

When a new scene is started, the Material Editor will not have any materials loaded in its sample slots. The slots all contain what 3DS Max calls a default material. You can load a material into a slot (for use in the scene) by first clicking a slot, then clicking the Get Material button, which is the first button on the left in the Material Editor's horizontal toolbar. (There is also a vertical toolbar. You can see both of them in the illustration on page 203.) Alternatively, if you only wanted to add a color to the default material in a slot, you could follow the procedure to do so in the exercises that follow, to set a custom color based on RGB (Red, Green, Blue) values or HSV (Hue, Saturation, Value) values.

On page 203, the text describes the functions of most of the buttons in the Material Editor, but it is unlikely that you will remember them until you use them. I will describe some of the concepts from that section here, with the understanding that you will learn the details about these concepts as you use them:

  • library - There is a materials library that comes with 3DS Max, to which you can add materials that you make, and materials that you harvest from scenes that you load.
  • show map - There is a show map in viewport button that toggles between showing the texture map for a material in the viewport, or only showing it when the scene is rendered. This is not important for materials that do not use maps. You should be aware of it because you may wonder why you cannot not see a map that you assign to a material.
  • hierarchy - Materials can have channels (parts) that can be arranged in a parent-child hierarchy.
  • material type - Different material types have different sets of properties, allowing them to be configured and used differently
  • shader type - Setting a material's shader type determines how it reacts to and reflects light in a scene
  • map buttons - The diffuse and specular color swatch buttons on the Materials Editor have map buttons next to them that you can click to browse for a texture map to apply to the material.
  • specular level - The brightness of the specular highlight.
  • glossiness - The size of the specular highlight.
  • self illumination - A large value here means that the material does not show shadows well, and that it does not require lighting because it glows.
  • opacity - High opacity means the material is more opaque, low opacity means that it is more transparent.

This is the last topic before we begin the project for this lesson. Shader types affect the way light is reflected from an object (several types are named for the people who developed them):

  • Anisotropic ("not shaped the same") - Have you ever seen the moon reflected onn water, so that it stretches out in only one direction? This one makes asymmetric reflections and highlights; suggested for brushed metal. Read this discussion of the effect as seen on water, on multiple reflecting surfaces, and on grainy surfaces.
  • Blinn - the default shader type; gives a round highlight, good for most materials
  • Metal - good for smooth metal material
  • Multi-layer - has two anisotropic parameters, to be set differently; recommended for shiny materials (like silk) whose layers reflect differently
  • Oren-Nayar-Blinn - a softer version of Blinn, good for cloth and skin
  • Phong - supports a shader from older versions of the program; similar to Blinn, highlights are not as round
  • Strauss - simple shader, not clear when to use it
  • Translucent - allows light to pass through it, can simulate self-illumination

The text provides a description of the real Red Rocket toy's wheels on page 205. Note the words used on this page and the next to describe the wheels: white, smooth, shiny, reflective. Compare these to the words describing the tires: black, still shiny, rough, distorted by bumpiness, slightly matte. The hubs of the wheels have yet another texture and look: red, shiny, plastic. These are descriptions that should be handled by mapping a different material to each part of the wheels. Each wheel is only one object however, so the text recommends using Multi/Sub-Object materials.

Project Exercise 1: Creating a Multi/Sub-Object Material 

This exercise starts on page 205. It returns to the Compact Material Editor. Set your project folder to be the Red Rocket folder, and open the supplied file named in the text.

  1. Open the Compact Material Editor. Choose the first sample slot. Name the material. (This can be done before you edit a material or after you have done so.)
    The book does not mention how to name the slot. If you have picked the first one (and why wouldn't you?) there is a box in the editor that says "01 - Default". Click in that box, remove that text, and type Red Bolt, as the book says. Press the enter key and the material is named.
  2. Blinn parametersBe aware that the Material Editor works like the command panels: the parameters area of the editor scrolls to show lots of rollouts, and what appears in that part of the screen will vary based on what you just clicked.
    Scroll (or drag the panel vertically) if you do not immediately see the Blinn Basic Parameters rollout. You would not even see it, by the way, if the Shader parameter were set to anything other than Blinn.
    Click the gray box next to the word Diffuse that my mouse pointer is over in the image for this step. That box is the Diffuse Color Swatch. Set the value for the Diffuse color for this material as instructed. Note that the Color Selector has spinner buttons. If you want to change the value for a field that has a spinner button to zero, you can just right-click it. (It will automatically go to the lowest possible value, which is 0 for color values.) Click OK on the Color Selector window when you are done.
  3. Watch the color sample change as you modify the values for Specular Level (higher is shinier) and Glossiness (higher is a smaller highlight).
  4. Select the next sample slot, name it, and set its Diffuse color. Note that the text does not tell you what values to use for white. Pure white is attained by setting the red, green, and blue spinners each to 255. You may want to vary this a bit, to get a more realistic tone. Set the Specular Level and the Glossiness the same as the previous slot.
  5. Select the next sample slot, name it, and set the Diffuse color to black. Again, you may want to use a variant of black, instead of setting all color components to 0. Note that you are told to set the Specular Level to 50 and the Glossiness to 20.
    Question 1: What are the general effects of setting the Specular Level to 50 instead of 90, and of setting the Glossiness to 20 instead of 80?
  6. Save the file with a new name, preferably one with your initials and a version number in it.

The text starts a new exercise. In it someone has made a terrible error: the picture in the text for step 3 has nothing to do with the instruction, which itself is uninstructive. Let's fix that.

Project Exercise 2: Selecting polygons and named selection sets 

This exercise starts on page 207. It has problems, so read it, then come back here for corrections.

  1. Continue in the file from the last exercise. Press F4 to see edges (unless they are already displayed), and press F2 to see selected polygons lit by their edges only.
  2. You should only see a wheel and a large part of the rocket model. Select the wheel as instructed. Don't bother going to Polygon subobject mode.
  3. This is the step where they tell you to select all the polygons in the tire portion. They specify no method, so you are left to obit the scene while trying to click every hidden polygon that you want. That's a silly way to do it. Do this instead:
    1. Change to edge selection mode. Isolate the wheel if you like, but it won't be necessary this time.
    2. You can Orbit the scene to get a view like the one shown in the three images below.
    3. Click outside the wheel to deselect any edges already selected. This is a useful habit when making a new selection: make sure you select only what you want to select.
    4. Click one of the edges that goes across the tread of the wheel. (See the red line in the first image below.)
    5. On the Graphite ribbon, Modify Selection tab, find and click the Ring button. The same edge in all positions around the wheel will be selected. (As shown in the second image below.)
    6. Click the Ring Grow button on the Graphite panel (it is the one with a plus sign just below the Ring button) and guess what? Nothing happens!

      Grow button on the Modify panelInstead, find the Grow button on the Modify panel, and click it three times. The selection set will grow toward the axle, in each direction, with each click. (The result is shown in the third image below.)


    7. d. Click an edge e. Click Ring f. Click Grow 3 times
      Pick an edge on the wheel Create a ring from the selected edge Use the grow command to expand the ring

    8. Hold down a Ctrl key and click the icon for Polygon subobjects. (It has to be the icon, not the word in the modifier stack.) The icons on the Modify panel and on the Graphite ribbon both work. This will select the polygons defined by the currently selected edges.
    9. Another good habit: save the selection set by clicking in the drop down box that says Create Selection Set, typing a name, and pressing Enter. Why? Because you don't want to lose that selection set right now, and if you save it when you save the file, you can reselect all of those polygons in a second if you need them again.
  4. Return to the exercise in this step.
    If it is not open, open the Material Editor, in Compact mode. Drag from the Wheel Black slot and drop on any of the selected polygons. The material will be applied. (You can drag and drop the material, but for a selection set it may sometimes be better to click the Assign Material to Selection button.)
  5. Stay in polygon mode, and try to area select the polygons for the white wheel cover. It will not hurt if you select the actual hub as well, since you color it next. Drag and drop the white material on the selection.
  6. Try using the edge-ring-polygon method from step 3 above, as well as the area selection method to put the red material on the actual hub of the wheel.
  7. Save incrementally and show me your work.

As the book proceeds to explain, you have now loaded an MSO material in the Material Editor by virtue of using three materials with one object. The three steps on page 208 confirm this.

Project Exercise 3: Loading the MSO Material 

This exercise starts on page 207. Continue working with the file you saved at the end of the exercise above.

  1. Multi-Subobject Material ParametersOpen the Material Editor and select the next unused sample slot.
  2. Find and click the eyedropper button next to the material name field. Click anywhere on the wheel as instructed.
  3. You should see a Multi/Sub-Object Basic Parameters rollout, but it may have more materials in it than you applied to the wheel. Mine has the three named materials, as well as three randomly numbered materials, indicating that there are at least three parts of the wheel that I have not applied a named material to at this time.
    Name the MSO material as instructed and save the file again.

Project Exercise 4: Fine-tuning the materials 

The text continues with some modifications to the materials, using more resources from the student disk. After some discussion, the exercise begins on page 208. In the course of the discussion, the authors refer to part of the model being hidden on separate layers. They are thinking of an older version of this exercise. There are no parts hidden in this scene. There is only one layer presently. (We can talk about layers in lab this week.)
Continue with the file you saved in the previous exercise.

  1. Open the Material Editor. The text says to select the Red Bolt material.
    1. Open the Maps rollout and find the line for Reflection.
    2. Click the Map button for Reflection that currently says None. (Yes, it's wide, but it's a button.)
    3. Click Bitmap in the list that appears, and click OK.
    4. Navigate to the Images folder for this project, and find the Rocket_Refmap_Blur.jpg file. Select it and click Open.
  2. Do a Quick Render of the Perspective viewport.


    Back to the lesson. The author has added a material that fakes a reflection of a scene in the surface of the bolt. You will see in the render window that the material is too reflective.
  3. Go back to the Maps rollout by clicking the Go to Parent button in the Material Editor's horizontal toolbar. Change the Reflection Amount value to 30. Render again to see the difference. This may not be the ideal value on your screen. Experiment, and find a value you like best.
    Question 2: What value looks best to you for Reflection Amount?
  4. Save incrementally.

Project Exercise 5: Applying a bump map 

The text mentioned that the surface of the tire portion of the wheel should look rougher than the white and red portions. Adding a bump map will do that. This exercise begins on page 211.

  1. Continue with the scene file from the previous exercise. Open the Material Editor and select the black material. Open the Maps rollout.
  2. Find the Bump line, and click the Map button for it. (It should say None at this time.) This time, click Noise, then click OK.
  3. On the Parameters screen that appears, find the Size field and change the value to 0.02. After you have made this setting, click the Go to Parent button.
  4. Change the Bump Amount value to 60.
  5. Render the viewport again, and enjoy your work.
  6. Save incrementally and show me a render of the scene.

Project Exercise 6: Fin base material 

We will move ahead to page 211 in the text. The author brings up the point that a map image will not always fit the object you want it to fit. There is inadequate explanation of what you are doing in this chapter. For a more informative discussion of the subject, follow this link to a tutorial on the UVW Unwrap modifier. For those who don't want to follow the link, I will do what I can here.

Maps are colors, patterns, or other coverings that we put on the surfaces of objects. In this lesson, we will look briefly at tools to use the UVW coordinate system on maps.

In general, U, V, and W are just the three letters that come before X, Y, and Z in the English alphabet (and others). So what? Well, the letters correspond to an artificial coordinate set. If X, Y, and Z are the Cartesian coordinates of a 3D object, U, V, and W are the coordinates we would use to measure the surface of that object if we peeled the surface off and laid it out flat, like skinning an animal to make leather. As you might imagine, a flattened pattern for a complex object will have a very unusual appearance. As such, we will use some special tools in 3DS Max to manipulate maps for 3D objects.

3DS Max uses the UVW Map modifier to apply maps to objects more precisely. There are several map types that apply to classic object shapes:

  • planar - for flat surfaces
  • cylindrical - for cylinders, with or without flat ends. If the cylinder has flat ends, we can use the Cap option to apply a planar map to the ends.
  • spherical - meant for spheres (ball-shaped objects). This one has a limitation we can overcome: the edges of a map will form a seam on one side of the sphere, and at the poles (points where the top edge meets itself, and where the bottom edge meets itself)
  • box - a classic six-sided figure, that may or may not be a cube

This exercise begins on page 212.

  1. Open the file specified in this step. Save it with your name incorporated in the filename. Select the fin on top of the model, right-click it, and choose Isolate Selection.
  2. Open the Material Editor. Select a sample slot, and set the Diffuse color for this slot to whatever shade of white you used for the wheels.
  3. Name the material as instructed. Drag and drop the material from the sample slot onto the fin.
  4. Set the Specular Level and the Glossiness for the material as instructed. Watch the fin change as you change each setting. (The material may look gray in a render window at this point, due to the lighting in the scene. Lighting comes up in another chapter.)
  5. Follow the instructions to add the same reflection map that you added to the wheels.
  6. Change the Reflection Amount to 35.
  7. Do a Quick Render to view the work so far. Modify the Reflection Amount, if you want to, then save incrementally. Continue to the next exercise.

Project Exercise 7: Adding the decal 

This exercise begins on page 213.

  1. If it is closed, open the Material Editor. Select the Fin_Decal Material.
  2. Go to the Maps rollout, and click the map button for Diffuse Color. Click Bitmap, and OK. Navigate to the file specified in the text. (It does not match figure 7.79.) Select it and click Open.
  3. The map will not appear in a viewport until you click the Show Shaded Material in Viewport button. Do so, and note that it looks a lot like figure 10.13. Not very good, yet.
  4. Step 4 seems unnecessary. We can already see the material in the viewport.

The text does not really begin a new exercise, but it starts a new set of steps at the top of page 214 to add a modifier.

  1. Close the Material Editor. In any viewport, select the fin, the open the Modifier List, and add a UVW Map modifier to it.
  2. Verify that you see the orange frame around the fin.
  3. Find the Alignment section of the modifier's parameters, and click the Bitmap Fit button.
  4. Navigate to the decal file again, select it, and click Open. The orange frame of the UVW Map gizmo should change shape to match the proportions of the tiff file.

Again, the text starts a new set of steps at the bottom of page 214. And they will do it again. This time the steps address adjusting the gizmo.

  1. Follow the directions in the text to open the UVW Map modifier in the stack, and to select its Gizmo element.
  2. You should see a gizmo in the viewports that starts out based on the Move tool gizmo.
  3. Select the Rotate tool on the toolbar.
    Read the instruction in the step but wait a minute. It says to rotate the gizmo on the X axis. I have puzzled over what the authors mean for a minute and I can say it more clearly.

    Use the Z handle on the Rotate gizmoLook at the model in the Left viewport.
    Turn on angle lock.
    Grab the rotate handle for the Z axis. (It should be blue, but it may be yellow even before you grab it.)
    Watch the transform value for Z at the bottom of the screen. It says 90 when I grab the handle, but it changes immediately to 0 when I begin rotating the decal clockwise, then the numbers become negative and start to grow.
    Drag the handle until the transform value reads -75.

    So, what were they talking about? We rotated the decal with the Z axis tool, which means it rotated using the Z axis as a center point. It is also true that it rotated through the X axis, but so what? It rotated through the Y axis as well. Another point of clarity: when you tell someone to rotate something, tell them which handle of the tool to use. That represents the axis it is rotating on.
  4. Decal has been rotated and scaledSwitch to the scale tool. Turn off the angle lock and turn on the percent lock. Drag down uniformly, and watch the transform values again. Stop when all transforms are down to 40. You will still see lots of emblems on the fin, but one will be centered and properly oriented.

 

Correcting the projection

  1. The text informs you that the decal looks fine on the left side of the fin, but the letters (and the image) appear reversed on the right side. Look in the Parameters rollout of the UVW Map modifier.

    (The text refers several times to the modifier as the UVW Mapping modifier. This is the name that used to appear in the modifier stack once it was loaded. This name no longer appears in the stack. They have not updated all the references in their old exercise.)

    Find the Mapping radio buttons, and change the mapping type from Planar to Box. (Planar might have worked well if this were a flag.)
  2. This takes us back to having the decal show on six faces of the fin. The fin is no longer meant to have six sides, so the author has a trick to make it work out.
  3. In the Mapping section of the Parameters rollout, find the Height parameter, and change its value to 0.01. (It is not allowed to be 0, so you make it a small value.)
  4. The value used makes the unwanted sides of the box very thin, so they won't be noticed.

The authors seem to have left out something important. Back on page 214, they told you a little about tiling, but they never mentioned that you should turn it off for this material. Follow these steps to finish the tutorial.

  1. Open the Material Editor.
  2. Select the material for the fin.
  3. If you see the Maps rollout, click the Map button for Diffuse color, which will take you to the properties for that map.
    If you are already on the properties screen that includes the rollout shown below, stay on it.
    Decal coordinates rollout
    .
  4. In the Coordinates rollout, shown above, note that there are two check marks to tile the map on the U and V axes. (U and V are like X and Y, remember?)
    Turn off the check marks.
  5. Nothing may seem to happen. Render the current view again. The decal should no longer tile in the render window.
  6. You can also modify the position of the decal on this rollout with the offset values. Do this, then render again and be horrified that the decal now appears in places it should not again.
  7. Changing the tiling removed the Box mapping corrections. Repeat those corrections, and check the model in rendered views again. It should be the best version so far.
  8. Save incrementally, and show me your work.