Chapter 8

Creating Advanced 3D Rendered Images for Your Web Page

-by Kelly Murdock

CONTENTS

As you work in 3D graphics, you will begin to notice an interesting fact: No matter how advanced your 3D image is, there's always something cooler. It's all part of the ever-developing nature of computer graphics.

Now that you've gotten the basics out of the way, you can move on to some more advanced modeling and rendering techniques. Keep in mind that advanced techniques are all relative. What's advanced to the newbie doesn't help the seasoned 3D artist.

In this chapter, you'll continue where you left off in Chapter 4, "Creating and Embedding 3D Rendered Images," and explore several miscellaneous topics that may be of interest. This is what you have to look forward to:

Now that you have your laundry list, get out your pencil and check these topics off as you cover them.

Modeling Complex Objects

Using primitives and borrowed models is definitely the easy way to build a scene. They usually require just pressing a single button or issuing a solitary load command. Deforming models doesn't take much talent either; everyone learned to do that with clay in kindergarten. So how do you go about modeling from scratch? Well, start by learning modeling terms, such as sweep, lathe, and skin.

You'll start this chapter off using Ray Dream Studio. Not that you couldn't use trueSpace, but you want to broaden your skills, and this is a great way to do it. Ray Dream Studio is especially good at modeling from the ground up. First, start with sweeps.

Modeling Using Sweeps

Remember back in Chapter 3, "Adding Simple 3D Elements to Your Web Page," when extrusions were explained? Well, extrusions don't always have to be along straight lines.

To sweep an object is to move its cross section along a path, and an extrusion is the simplest sweep case. In Ray Dream Studio, the Free Form Modeling Window is where most of your custom modeling takes place. Take a look at an example:

  1. Open the Free Form Modeling Window by dragging the Free Form icon from the toolbar at the left onto the scene. This will open the modeling environment and present a dialog box where you can name the model.
  2. To make the letter J with a circular cross section, start with a circle. Select the Draw Oval tool from the toolbar. You might have to hold the mouse button down and drag to the right to select the Oval tool. The Shift key constrains the Oval tool to draw a perfect circle. Draw a circle on the drawing plane (the one that floats free of the others) by dragging the mouse.
  3. This action creates a simple cylinder. The pink lines on the left and bottom planes are your sweep lines. Add six more points between the endpoints of the sweep line on the left plane with the Add Point tool. Corresponding points show up on the bottom plane's sweep line at the same time.
  4. Click the Selection arrow at the top of the toolbar, then click in the window away from the sweep line to deselect the points just added. Next, move the points one by one to form a new sweep line, as shown in Figure 8.1.

    Figure 8.1 : Sweeping the letter J in Ray Dream Studio's Free Form Modeling Window.

    Tip
    You can select preset views to look at only one plane at a time by using the View | Preset Position menu command.


  5. Use the Geometry | Extrusion Method | Pipeline setting to make the circular cross section remain perpendicular to the sweep path. The Translation setting sweeps the path while keeping the cross section vertically aligned.
  6. When finished, click the Done button in the lower-left corner of the Free Form Modeling Window to return to the Scene Window.

There are a lot of options when sweeping, but they're all based on the same simple concept.

Lathing Models

Lathing creates objects by rotating a profile around the center axis. If you remember how the wood lathe back in shop class worked, you've got the right idea.

Two things are needed to perform a lathe: an outer profile and an axis to rotate around. However, you don't need to rotate the full 360 degrees, as you do with a wood lathe. You can rotate only part of the way, so it's easy to create a full watermelon, half a watermelon, or just one slice.

In Ray Dream Studio, you'll use the Free Form Modeling Window again to perform a lathe. The profile is referred to as a Scaling Envelope. Just like wood shop, try creating a baseball bat for old times' sake.

  1. Open the Free Form Modeling Window by dragging the Free Form tool into the Scene Window.
  2. Draw a circle on the drawing plane by holding the Shift key down while you drag the Oval tool.
  3. Select the Sections | Center command to center the circle in the window. Next, choose Geometry | Extrusion Envelope | Symmetrical to enable the Scaling Envelope, which shows up as four blue lines.
  4. Add points to the top blue line in the left plane and move them with the Selector tool to form the bat profile. The Symmetrical setting causes the same points to show up on the other envelope lines.

That's all there is to it, and no wood chips. The finished bat is shown in Figure 8.2.

Figure 8.2 : Your completed lathe-a baseball bat.

Skinning: Creating Models with Multiple Cross Sections

If you start to use sweeps and lathes, you'll soon find that they are useful for creating simple models, but many objects don't have a common cross section throughout. Most objects have different cross sections along their length. These types of objects can be modeled using a process called skinning.

Skinning is sometimes called lofting, after the process used to build ships. Ship builders would arrange the cross sections of the ship along its length and then fasten the ship's surface to these cross sections.

In Ray Dream Studio's Free Form Modeling Window, you can create several different cross sections and the surface will smoothly move from one to the next. Try creating a screwdriver as an example:

  1. Enter the Free Form Modeling Window and name the object Screwdriver.
  2. Choose the Sections | Create Multiple command and enter 9 in the dialog box so your screwdriver will have nine cross sections.
  3. Click on the back plane to see the first drawing plane. Draw a small circle for the first cross section and choose Sections | Next to move to the next drawing plane. The screwdriver handle cross section was drawn using the Pen tool to place points. Repeat this for each drawing plane until you've drawn all the needed cross sections.
  4. Click on one of the sweep paths. All the drawing planes show up as evenly spaced points. With the Selection cursor, move these points until the section has the right length. You will need to place some points on top of one another, such as where the handle connects with the shaft.
  5. You can edit the cross sections by clicking on them and moving the points. You can remove the current drawing plane by choosing the Sections | Remove command or by using the Delete Point tool to remove the corresponding sweep path point.
  6. For each cross section, you can use the Sections | Cross Section Options command to open a dialog box that will let you set whether the cross section is filled or disconnected from the next cross section.

Drawing planes aren't limited to only one cross section per plane; they can have multiple cross sections. The Sections | Show Shapes Numbering command lets you see which cross sections are connected. Double-click the number to change the association. Figure 8.3 shows two shots of the final screwdriver.

Figure 8.3 : A screwdriver model created with Ray Dram Studio by skinning over several different cross sections.

The individual parts that are built using the Free Form Modeling Window can be combined into a hierarchy to create complex models. The windmill, taken from the Ray Dream CD-ROM, shows in Figure 8.4 an example of a complex model created entirely from primitives and free-form modeled parts. By double-clicking on a part or on its name in the hierarchy list, you can launch the part into the Free Form Modeling Window for editing.

Figure 8.4 : This windmill is a fine example of a complex model mode from primitives and free-form modeled parts.

There are more ways to model, which are covered later in the chapter, but while you have Ray Dream Studio open, look at some render settings that can add realism to your images.

Using Environmental Settings

No, this section doesn't talk about recycling or how you should use bicycle models instead of cars to save on pollution. In 3D packages, environmental settings are special commands you give to the render engine that affect the way the image is rendered. Examples include reflection maps and fog effects. Each package will call these settings something different. Ray Dream Studio refers to reflection maps as reflected backgrounds.

Casting Reflected Backgrounds on Your Rendered Images

In Chapter 4, you learned how to add backgrounds to your images. They acted like backdrops that enhanced the image, but didn't really affect the models in the scene. Reflected backgrounds are images projected from all sides toward the models and are reflected off any reflective objects within the scene.

Reflected backgrounds are also sometimes called Environment Maps. They can add a great deal to your images without requiring many additional models and can be used as an alternative to ray tracing in some cases. Take a look at how Ray Dream Designer uses reflected backgrounds.

  1. Start by setting up your scene. For the scene in Figure 8.5, I used the Scene Wizard as a start. This gives me a jump on the scene by automatically placing lights and the backdrop.

    Figure 8.5 : A balloon in the sky showing the cityscape below in a reflected background.

    Tip
    Reflected backgrounds show up best when reflected off a model with a large smooth surface area, such as an apple, a car fender, or a window.


  2. Once the scene is set up, select Render | Effects to open the Render Effects dialog box. Select the Reflection Background tab and choose Map in the top pull-down menu and open the image you want to use.
  3. The other buttons in the dialog box let you flip or rotate the image. You can also tile the image.
  4. Next, make sure that renderer is set to RDI Ray Tracer by choosing the Render | Settings command and looking in the Renderer tab.
  5. The final step is to render the image with the Render | Render | Use Current Settings command.

Tip
Because of the time it takes to render a scene, you may want to render it using the Low Res Preview option to check the image before it starts the final rendering.

Adding Fog Effects to Your Rendered Scenes

There are other environmental settings you can add to your scene. One that frequently shows up in 3D packages is the ability to add fog to your rendered scene.

The fog settings for Ray Dream Studio are also added by using the Render Effects dialog box:

  1. Starting from the Scene Wizard once again, position your models and set up the scene.
  2. Select Render | Effects to access the Render Effects dialog box and go to the Atmosphere tab. Ray Dream has three types of fog available: normal, cloudy, and laminated. Using the dialog box controls, you can adjust the fog color and its density and lumpiness, among other things.
  3. With the scene ready and the render effects set, render the scene to see the fog. The cloudy fog setting was used in Figure 8.6.

Figure 8.6 : A raptor in the early morning forest, complete with misty fog.

Within the Render Effects dialog box, there are other environment settings, such as Ambient and Backdrop. Other packages have unique features also, but they all work in roughly the same way, by manipulating the settings before rendering.

Using Photoshop to Touch Up Your Rendered Images

Imagine the following scenario. You've completed your scene, you've got the models in just the right positions, and you've previewed the image a number of times-finally, it's perfect for your Web site. However, after rendering all night, you realize it needs just a little more light in that one area, or you think of another effect that will increase the coolness factor by 14.

This is a common occurrence for 3D artists. Seldom does an image turn out perfectly on the first render. I suggest you do a lot of preview renders, but even those can't see everything. Now for the glimmer of hope. Sometimes you can correct small mistakes and even enhance your image in ways that weren't possible using your 3D package, with help from an image-editing package like Photoshop.

A good example would be in adding some text on top of the rendered image. This can be difficult to line up in the 3D scene, but it's easy to add in Photoshop. Take a look at the following example:

  1. Load your rendered image into Photoshop. I'm using a scene created by Ray Dream's Scene Wizard. The original rendered image is seen in the upper-left corner of Figure 8.7.
    Figure 8.7: Your rendered image touched up with Photoshop.
  2. The first enhancement you want to add, using Photoshop's Lens Flare tool, is a specular reflection off the window. Select Filter | Render | Lens Flare to open the dialog box. I used the 50-300 mm zoom lens with 25 percent brightness. The results are shown in the upper-right corner of Figure 8.7.
    Figure 8.8: A charcter modeled in splines and patches with Martin Hash's 3D Animation.
  3. The next enhancement is to add some artistic sticks in the empty flower pot. These sticks would be a lot of needless polygons in the 3D scene, but in Photoshop they are simple black lines painted on in no time.
  4. The final enhancement, shown in the lower-right corner, adds some text to the scene.

Exploiting the Advantages of Spline and Patch-Based Modeling

Just as you are starting to get the hang of two different 3D packages, you're going to shift gears again. Why, you may ask? Different packages use different modeling paradigms. You've learned about the most popular types, but there are others.

trueSpace and Ray Dream Studio are both polygonal modelers, which means that all their models can be broken down into lines and polygons. This works well and can represent any shape you could want, but there's another way to model-using splines and patches.

Splines were introduced in Chapter 4 when paths were covered. Splines have the unique benefit of being easily controlled. To bend a polygonal line, you need to add more points and create a contour. To bend a spline, you simply need to move the control point handles. Therefore, a curved polygonal line takes many points, but a curvy spline needs only four points, or two points and two handles. This is far fewer points that the computer has to deal with, resulting in simpler models with more curves.

Many high-end modelers use spline-based models because of the control it gives them over models, but there's a 3D spline-based package that fits in your price range-Martin Hash's 3D Animation. I will refer to the product from here on as MH3D for simplicity's sake.

You'll use this package to introduce spline-based modeling and to show you how it can help create character models where curves come in handy.

Character Modeling Using Martin Hash's 3D Animation

You can model many different things, but modeling characters is perhaps one of the most popular, and difficult, tasks. Most entertainment centers around characters. Whether they're watching TV, cartoons, or sports stars, people like to identify with characters who have a definite personality, whether it's good or bad.

Try smiling at yourself in the mirror. See how your skin smoothly folds back into your cheeks as you grin? This action is very difficult to simulate with polygonal models because the computer has to compute how the polygons smooth from one polygon to the next. For tight curves, like right next to your lips, it's difficult for the renderer to tell whether the edge should be smooth or hard. This is where splines come in. Splines inherently "know" whether an edge is hard or smooth because that's how they are built. This ability means the computer doesn't have to guess how to smooth a polygon, so it's much easier to render and results in a better model.

MH3D excels at creating animations. In fact, to use the modeler, you need to define a path first. You'll get into the animation side of MH3D in the next chapter, but for now, examine the program to see what those splines and patches are all about.

Now you'll create a simple character named Clumgy by using MH3D. I don't know what kind of personality Clumgy will have, but with splines, he'll be able to smile very nicely.

  1. Click the New icon to create a New Choreography called Clumgy. MH3D opens the Direction window that shows the top view of your scene. The green box is the camera, and the four projecting purple lines are the camera's scope. The Direction window is where you control the animation.
  2. Click the upper-right icon in the floating toolbar, then click in the window to add a path to the scene. Now click the Add a Figure to the Selected Path icon that looks like a little human figure. This brings up a Figure dialog box. Click on New and type in Clumgy to open the Character module window.
  3. The Character window is where all the parts are assembled and grouped. Click the Add a Child Segment icon in the upper-right corner of the toolbar, then click in the window. Name the new segment "Head." The Sculpture window then opens for you to start modeling.
  4. Switch to the Front view by pulling down the View menu from the top toolbar, if you're not already there. Click the Add Mode button in the upper-right corner of the floating toolbar, or just hold down the A key while clicking and dragging in the window to create control points. You'll need about eight points for the head's cross section.

    Tip
    MH3D is much easier and quicker to use if you learn some of the basic keyboard commands. Almost every command has a single keystroke that invokes an action. For example, holding down the Z key lets you zoom in and out of the scene with the mouse.


  5. Click the arrow icon to move into Edit mode, and move the points to create a head profile. You can select several points at once by clicking the Enter Group Mode button (keystroke G) and dragging the box over the control points you want.
  6. Once the profile is correct, click the Enter Pivot Placement Mode button (keystroke P) and click in the window at the point you want to lathe the object around.
  7. Select all the points in the profile with the Group tool. Remember the Lathe tool? Well, along with the Extrude tool, it followed you here. Click the Lathe tool (keystroke L) to create the lathed head, which you can see in Figure 8.8. Close the Sculpture window to return to the Character window.

    Tip
    Check out the model by clicking on the Preview tool (keystroke Q) in the top toolbar, then clicking in the window. A shaded view of the head begins to render.


  8. In the Character window, click the Add Segment button (keystroke A), then name the segment "Right Eye." Use the Sculpture tools to create an eye, and return to the Character window. Copy and paste the eye to create a segment called "Left Eye."
  9. Continue this process for each body feature. In the Character window, the Edit Segment's Attribute button (keystroke f3) brings up the Attributes dialog box where you can specify the material used to render the body parts. When you're finished, save the character; you'll see how to animate it in the next chapter.

Your character's shown in the three different windows of MH3D in Figure 8.8. He isn't really that handsome, but not bad for a spline-modeled character with marshmallows for eyes and a pickle for a nose.

Using StudioPro's Metaballs

You've learned how to model with polygons and patches, so now look at another fairly new method called metaballs. Metaballs are like the equivalent of sticky spheres of clay. They're especially good at modeling rounded surfaces since they're made of spheres.

Isolated metaballs look just like normal spheres, but when they're placed next to one another, the surface of one flows into the surface of the other, much like drops of mercury. You can control the level of attraction between the surfaces.

Several programs, such as StudioPro, are beginning to offer metaballs as a modeling option. Take a look at how metaballs can be used in the following example:

  1. Start by placing spheres in your scene; make sure they overlap.
  2. Select all the spheres you want to make into metaballs. Then use the Modeling | Metaballs | Join command to open the Metaballs dialog box where you can specify the influence each sphere has on its adjoining spheres.
  3. Clicking the OK button causes all joined spheres to exhibit metaball properties. An example of how this works can be seen in Figure 8.9.

Figure 8.9: Bubble man before and after being converted into metaballs.

Creating Models from Photographs with PhotoModeler

If all these lines and points and axes are just too confusing, you might want to look into another new modeling technique. PhotoModeler takes regular photographs that have been scanned in and uses visual keymarks to create a model.

The models created with this technique aren't extremely detailed, but by using the photos as texture maps to cover the surfaces, the models end up looking quite good. Because of the low polygon count, these models are especially handy for creating VRML worlds, so remember that when you start to create VRML worlds.

Now look at how PhotoModeler can be used to create a simple model of a computer monitor:

  1. Open a new project with the command File | New Project. A dialog box opens where you can give the file a name and approximate dimensions. PhotoModeler uses these dimensions to create a box to help you line up the pictures.
  2. Next, click the Photo Import button to open the Photo Import dialog box. Load your scanned photos into the project by changing to the correct directory and clicking the arrows button. Click the OK button when you've got all your photos loaded.
  3. With the Project Photographs dialog box open, select one of the photos and click the Position button. To tell the program how the photos fit into the scene, you need to know roughly where the camera was when it took the picture. Drag the camera in each of the three scenes until the cube with the specified dimensions is lined up with the picture.
  4. Set the camera position for each photograph in the same manner. Notice how the outline of the dimensioned cube has colors that match the box in the different views.
  5. Next, you need to mark specific points as they show up in each photo. Open a photo from the Project Photographs dialog box and enter Marking mode by selecting Marking | Mark Points. The cursor changes to an X. Click on recognizable points in the photo, like the corners of the computer monitor.
  6. Use the Markings | Mark Lines command to mark lines within the photo. Repeat marking points and lines for each photo. Each point will have its own number, which is visible in the status bar at the bottom of the window.
  7. Next, you need to refer to the various points to let the computer know which points match up in the different photos. Select Referencing | Reference Points to enter Reference mode. Open all the photos and select one point, then click on another photo and on the matching point in that photo. Continue until you've matched up all the points.
  8. The final step of the process is selecting Project | Process. After some calculations, a 3D model is created. To see the model, choose Project | Open a 3D Viewer. It shows up as a series of points and lines. The final model can be exported as a DXF or VRML file.

There are many more features to this program, such as applying surfaces and checking the accuracy of the model. The finished model for this example is shown in Figure 8.10.

Figure 8.10 : A simple 3D model of a Computer monitor created from photographs.

Modeling Complex Scenery with Terrain Generators

As you look into all the 3D packages (see appendix A, "3D Software Resource Guide"), you'll see that some produce only certain kinds of models. Two good examples are VistaPro, which creates landscapes, and Fractal Design's Poser, which creates only human models. Poser is covered in the next section.

Scenery can be very relaxing and inspiring, and many photo albums are made up of such pictures. So it's only natural for 3D modelers to want to create such images. Lucky for the modeler, there are several good packages especially designed for this type of modeling, such as Virtual Reality Laboratories' VistaPro, Metatools' KPT Bryce, Questar's World Construction Set, and Animatek's World Builder.

These packages usually start with a 2D grayscale image in which the darkness relates to the height, so the blackest areas would be the highest peaks and the white areas would be the lowest. This feature makes it easy to create gradually ascending mountain sides by using a 2D image with a gradual transition from white to black. It also makes it easy to add random peaks.

One of the toughest problems with creating scenery is including foliage. It's simple to create desolate moonscapes, but creating a rich, lush mountain scene is much more difficult. Some of these packages include details like trees, shrubs, and flowers that can be added to the terrain. You can further define the range of these details so that they're not visible from far away, but show up with greater clarity as you get closer. An example of the type of images these packages can create is shown in Figure 8.11.

Figure 8.11 : A sample picture created using Animatek's World Builder software.

Positioning Human Figures with Fractal Design's Poser

Think of how the Greeks modeled the human body. Their statues took many months to create, but were detailed and impressive. Today, computer artists find many places to use models of human figures. Whether in an architectural scene or a recreation of a historical event, human models can add a personal touch to any 3D scene, but only if they look realistic.

There are 3D human models available, but they can be difficult to use if you try to reposition them, so you end up getting a human model that's standing, one that's sitting, one that's running, and one that's jumping-or you get Fractal Design's Poser.

Poser lets you choose from several human types-male, female, hero, and mannequin-and from several different heights, such as baby, toddler, and adult. Once you've selected your model, you can position it by using inverse kinematics. To make your model do aerobic knee lifts, just grab its knee and pull it up. Follow these steps to see how this works:

  1. When you start Poser, the default is a male figure standing with his arms out straight. The Tools palette will be open with the Pose mode selected.
  2. Start posing your figure by clicking on the man's chest; when you do that, the chest turns white. Then drag the mouse to the right; his upper torso follows, making him lean to the right.
  3. You don't want this man to be alone, so introduce a dancing partner. Select Figure | Add Figure | Female Body to add a female figure.
  4. Click on the Move icon to change to Move mode, then click on the icon with four arrows, which is the Move icon. Now move the female figure to the left.
  5. Return to Pose mode by clicking the Pose button and reposition the female arms, as shown in Figure 8.12.

    Figure 8.12 : A scene from a ballet composed in Fractal Design's poser.
  6. When you're done posing your figures, choose Render | Render to create a rendered image.

Figure 8.12 shows the figures in a ballet step-and don't worry, Poser supports texture mapping, so you can add clothes to your models. If you plan on working with human models often, Poser is a great tool and easy to use. You can also export your models as DXF files to be imported into other 3D packages.

Using Conversion Utilities

You're probably starting to notice that the features of all these different packages vary quite a bit; no one package has exactly the features you want or need. The truth is that 3D artists typically use a variety of tools. This raises the question of how you can load one model into another without losing any of the information-that's where conversion utilities come in.

Almost every 3D package has its own proprietary file format. Each package can import and export several different formats, but it's often difficult to move between packages. Some import and export functions have difficulties with certain formats and may lose material or hierarchy information.

To move a 3D file between formats, you might need to convert it a couple of times. Moving a Ray Dream Studio file to trueSpace requires exporting the Ray Dream file as a DXF or some other generic format and importing it into trueSpace. In Figure 8.13, you can see the results of file conversion. Two images on the left, the top one created in Ray Dream Studio and the bottom in trueSpace, were converted to the other program. You can see that conversion doesn't always give the best results.

Figure 8.13 : Two scenes created in Ray Dream and trueSpace, then converted, loaded, and rendered in the opposite package.

With the introduction of VRML as a new file format, many 3D programs are introducing an export feature to VRML. Chapter 13, "Exploring VRML Browsers and Development Tools," covers a number of specific VRML conversion programs.

Several programs are available that handle file conversion. One of the best file-conversion pieces of software is produced by a company called Okino. The product is the NuGraf Rendering System. Not only is it a full-fledged RMA, but it can import and export more file formats than any program I've seen.

Look at how NuGraf's batch conversion feature works:

  1. When the program starts, you see a dialog box that lets you start in Beginner or Expert Mode. Select Expert Mode. You can switch back to Beginner Mode using the Options | Switch to Beginner Mode command, but the Batch 3D Convert command is available only in Expert Mode.
  2. Open the Batch Convert dialog box by selecting the File | Batch 3D Convert command.
  3. Click the Add Files button to select the files you want to convert and select the Export format at the bottom of the screen. When you're ready, click the Convert Files button.
  4. The export options for each type of model are in the Options dialog box. Select the options for the conversion process and click OK.

The NuGraf Rendering System also has a fast, efficient renderer and many advanced features, such as a tip-of-the-day box, model optimization commands, and unlimited texture layering. You can see its interface in Figure 8.14.

Figure 8.14 : A screen shot from the NuGraf Rendering System program.

Workshop Wrap-up

The purpose of this chapter wasn't to scare you, but to show you the broad scope of technologies involved in working with 3D graphics. Every year there are new and better techniques introduced that make the process easier and push the envelope of what's possible.

Next Steps

So where do you go after learning about creating advanced rendered images? Actually, anywhere you want, but I would recommend the following:

Q&A

Q:
If these technologies are changing so much, where can I go to find the latest technologies?
A:
There are a variety of books, magazines, and resources on the Web that cover these issues. This book's CD-ROM has a resource guide to get you started.
Perhaps the best forum for keeping up on computer graphics is the annual Siggraph convention held early in the fall. Each year researchers, exhibitors, and artists gather for a week-long conference in which the latest and greatest in computer graphics are presented. If you're interested in computer graphics, don't miss this show. You can find information about the conference at http://www.siggraph.org.
Q:
I really want to use the features you've mentioned in this chapter, like metaballs, particle systems, and terrain generators. Do I have to buy an entirely new product to get these features?
A:
Luckily, you're not alone. Many good shareware programmers have grown weary waiting for the latest features to appear for their favorite modeler, so they've written shareware programs to use some of these features.
Examples of some of these shareware programs are on the CD-ROM. Check out Blob Sculptor for metaball functions and Landscape Maker by Kevin O'Toole for terrains.These tools and many others can be found at the Avalon site at http://www.viewpoint.com/avalon. Another good shareware tool is Exploder by Rob Bryerton, which creates particle systems for trueSpace. It can be found on the Caligari site at >http://www.caligari.com.
Q:
You've mentioned splines in this chapter, but I've heard there are different kinds of splines. Is this true?
A:
Yes, there are a number of different types of splines, each with its own advantages. The major difference is in how you control the curvature. The mathematics behind the curves cause them to behave differently.
Bezier curves were one of the first types to show up in typefaces and drawing packages like CorelDRAW!. Another type you'll see in the CAD world is NURBS, which stands for "non-uniform rational b-spline." Some 3D packages are starting to use NURBS