CAP 201a - Computer Animation I

Lesson 3 - Files and Objects


This lesson introduces the user to saving and combining files in 3DS Max. Objectives important to this lesson:

  1. Saving files
  2. Saving and retrieving a temporary file
  3. Combining files
  4. Using a grid
  5. Elements of an object
  6. Grouping objects (discussed in the exercises)

This chapter returns to presenting lecture material first, then presenting exercises to practice it. Be careful: it also presents a lot of new material in the exercises, so you really need to read the whole lesson. (You were going to do that anyway, right? How about from now on?)

The lesson opens by reminding us that we are working with scene files, which are saved with a .max file extension. (If you are the kind of user who does not tell your Windows computer to stop hiding extensions of filenames, get over it and turn the hiding off. Anyone who works with files should be able to see the whole name, not just part of it.)

It may help to think of scene files like scenes in a movie. Each scene typically takes place in one location. You can make a series of scenes that can be combined in your animation project.

The text points out that you can use the Save As command (like the one found in any other software package) to save a file with a new name each time you make a significant change in it. The Save As dialog box for 3DS Max has an additional feature: the Plus button can be used to increment a version number for the file you are saving. That version number (automatic sequence number) becomes part of the filename. Whether you use a new name each time, or the same name with a new number, it is a good idea to have a series of versions of major files, just in case something goes wrong. You may lose a file, or you may need to go back in time to an earlier version to change what you did. Different versions of a file give you a way to roll back the clock to a time before a mistake was made.

The Hold command will save a temporary copy of the current working file. The Fetch command will open the current temporary file, and replace the current working file with it. This gives you an immediate way to save your place, try something out, and undo that something if you want to. The advantage of these commands is that you do not have to name a file, or increment its name. Also, making the temporary file does not affect any copy of the file you have already saved with a name.

You can merge files together to add features. This is like copying objects from a saved file and pasting them into your current working file. You should be aware of the process:

  1. Open one .max file. (Or create a new one.) For example, start a new file and create some scenery in it.
  2. Start the Merge command.
  3. Choose a second .max file. For example, pick a file that only has a character in it.
  4. Choose which elements (objects) you want from the second file.
  5. Finish the merge. The elements selected from the second file are now part of the working version of the first file. The second file is unchanged and you have not yet saved the changes to the working file. Another way to say this is that the file you are merging material into (the open file) is the one that changes. The file you are merging material from (the closed file) stays the same.

You can also select specific objects in your current working file and save them to a new file, without saving other objects from the current file. This is like copying those objects and pasting them into a new file. To do this, use the Save Selected command.

The Import command allows you to open files made in other programs, and the Export command allows you to save files in formats understood by a few other programs.

File Link and XRef are used to link files together so that when a change is made in a linked file, your file will show it automatically. This is only recommended in environments where all files are readily available to people using them.

The text describes two settings that you may want to customize for a scene you are working on: Units and Grid. Units should be set to particular units of linear measurement that are useful for your scene, such as US Standard (English) or Metric. The Grid command allows you to show a reference grid on your development panels. The Grid Settings command allows you to set how far apart the grid lines will be drawn (Grid Spacing), and how far apart dark grid lines will be drawn (Major Lines Every Nth Grid Line). Grid lines are like using graph paper in your 3DS environment.

Exercise Notes and Questions

Note: Exercises should be carried out in the classroom. You will not get very much out of them by just reading, nor will you learn what is required by just experimenting on your own. Each exercise is meant to cover specific content that you will be required to know.

Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.

Exercise 1: This exercise shows you the options for Units Setup. Note that the dropdown lists for each type are not available unless you click the radio button for that type.
Question 1: Which menu is the Units Setup choice on?

Exercise 2: Exercise 2 shows you how to modify the Grid settings for 3DS Max.
Question 2: Which setting is used to control the heavy grid lines?

Exercise 3: This exercise begins with new information about pivot points. A pivot point is the point in an object that you can rotate it around. In this exercise you will change the location of an object's pivot point, to see how this affects what kind of rotation you can do with it. Note that the pivot point for an object does not have to be located inside the object.
Question 3: The text gives you a useful mnemonic: RGB=XYZ. What does this mnemonic mean?

Exercise 4: Exercise 4 introduces more new material. Each of the viewports has a base plane, an imaginary flat surface that objects are created on for that viewport. (This was called a creation plane in another exercise.) The base plane for each of the orthographic viewports is a plane parallel to the one you are looking through, where the the value of Z is zero. (Remember: Z points a different direction in each view.)
For example, the base plane of the Front viewport starts out as the back of the scene. The base plane of the Top viewport starts out as the bottom of the scene. Why "starts out as"? Because you can move objects beyond the base plane, effectively moving the walls of the scene. The base plane remains at a depth of 0 with respect to that view.
Question 4: What is the base plane of the Left viewport for a new scene?

The exercise continues to show you how to select more than one object in the same scene. This is done by holding down the control key (Ctrl) while clicking each object. This is not new, but it is a good reminder.

Exercise 5: Before starting exercise 5, the text reminds us that we should create objects with tools on the Create panel, but we should modify them with settings on the Modify panel. This avoids creating objects that we did not mean to create, and it gives us finer control over the objects we did want to create. The exercise illustrates the point by having you create two cylinders, making them close to the same size by eye. (You use the Cylinder tool, but not the Modify panel.)

The exercise asks you to modify the face count of one cylinder. This term requires you to understand a couple of other terms. First, you can think of the number of sides of a cylinder as the number of lines used to approximate a curve. This corresponds to how many line segments are used to make the circle that the cylinder is based on. Follow this link to an image of a Susan B. Anthony dollar. The shaded part of this coin shows how the curve of its circle is approximated by an eleven sided hendecagon. (This shows that eleven sides are not a very smooth approximation of a circle.) 3DS Max will approximate smooth curves with a series of line segments. You can modify the number of sides.

Next, another feature of an object is its number of height segments. If the number of sides of a cylinder is the number of line segments used to approximate a circle, the number of height segments can be imagined as the number of additional circles used to create the object on the screen, in addition to the base circle. In other words, if a cylinder is drawn from its base circle and one more (the top of the cylinder), that is one height segment. If it is drawn from the base circle, the top circle, and four more circles in between, that is five height segments. Again, you can modify the number of height segments for an object.

So, suppose that a cylinder has five height segments, and has twenty sides. We can multiply sides times height segments to approach the face count: the number of faces (separate calculated surfaces) that the object has. That object should have one hundred faces. In fact, if we press 7 (as the exercise tells us) we find that the object has 200 polygons.

Why twice as many as we thought? 3DS Max has a special definition of "face" at this stage. A face is a surface defined by three points, a triangle that is a calculated subobject of the object we are creating. Each of the "real" surfaces of this cylinder has four vertices: a rectangle. Each of those rectangles is subdivided by 3DS Max into two triangular faces by drawing an imaginary diagonal line across the rectangle. This is what 3DS Max will count for the face count. Why do we care? It takes more memory to draw more faces. Reducing the number of faces in a scene will reduce the file size, the render time, etc.

Before beginning exercise 6, the text returns to methods of selecting objects.
Question 5: How do you select one object?
Question 6: How can you select two objects at opposite sides of the scene (and no others) by clicking?
Question 7: Can you select two objects at opposite sides of the scene (and no others) by dragging?

The text mentions that you can deselect an object (remove it from the selection set) by holding down an Alt key while you click the object. Note that set of all objects currently selected may be called the selection set, or just the selection.

Once a complex set of objects has been selected, you may want to use the Selection Lock Toggle button. Turning this button on locks the set of selected objects. Turning this button off unlocks the set. You would do this to avoid accidentally adding to or subtracting from the set.

The text seems to be afraid that we will not be able to select all the objects we want. The scene may be too crowded. When this is so, we can use the Select by Name button to present a list of objects. This leads the text to suggest that the default names given to objects by 3DS Max could stand some improvement. So, it recommends that we learn to use the Rename Objects tool.

Exercise 6: This exercise presents a lesson on renaming objects. You are introduced to the Select Object dialog box, which can be accessed by clicking the Select Objects by name button or by pressing the letter H on the keyboard. Work through this exercise to become familiar with its method of renaming objects.
Question 8: The exercise tells you to click the Zoom Extents Selected button. How do you get to it?

Hiding objects was introduced in a previous lesson. That lesson used the Quad menu to hide a selected object. The text shows us another way to do this: click the Tools menu and select Display floater. This turns on a floating Display menu that can be used to Hide, Unhide, Freeze, and Unfreeze objects. Hiding makes the object invisible in the scene. Freezing makes the object unalterable in the scene.

A related way of changing what you see in your scene is to use Isolation Mode. This choice shows only the objects you have currently selected. Open the Tools menu and select Isolate Selection to use this choice.

Exercise 7: This exercise begins with another version of the gas station. It practices using the selecting by name feature and the renaming feature.

The text discusses organizing objects before beginning the next exercise. Five methods of organizing objects are mentioned:

  • Give objects meaningful names
  • Name your selection sets to be able to use them again
  • Create groups of objects to modify and manipulate them together
  • Attach objects to each other, to make complex objects
  • Use layers to hide and freeze all objects in a layer at once

Exercise 8: This exercise demonstrates features related to Selection Sets. You create a selection set, add objects to it, and remove objects from it.
Question 9: When you create a new Selection Set, which drop down do you use? What must you do after typing the new set's name?

The lesson continues with an exercise about Groups. Before starting the lesson, it lists some features that may help in deciding whether to make a Selection Set or a Group.

  • Items in Selection Sets can be selected independently (without selecting the set).
  • Objects in a Group can be selected and modified together (as a group) or can be modified separately by Opening the group and detaching the objects. The objects can then be attached to the group again, and the group can then be Closed (reset as a group).
  • A Group is treated as a single object. The objects that are in the Group cannot be selected separately from the Select Objects dialog.

Exercise 9: This exercise demonstrates features related to Groups. You create a group, open the group, detach objects from it, attach objects to it again, and close the group.
Question 10: How does creating a Group affect the number of objects in the Select Objects dialog box?