3ds Max 9 Bible

When you start to model a cloth object, keep in mind that the model must have enough resolution so that it can accurately fold over itself several times. If the resolution isn't defined enough, then the bending of the cloth is not believable.

You can increase the resolution of a model in several ways. The Garment Maker modifier includes parameters that can increase the resolution of a mesh, or you can use the HSDS modifier to increase an object's resolution.

Using Garment Maker to define cloth

Clothes can be added to models using a method that is similar to the way real clothes are made. Each section of cloth, called a panel, is outlined using lines and splines in the Top viewport. Clothes patterns also can be imported and used. Include a break at each corner of the panel or the modifier will round the corner. After you have all the various panels created, convert one of the panels to an Editable Spline object and attach all the panels into a single object. You can apply the Modifiers Cloth Garment Maker to the set of panels.

When the Garment Maker modifier is first applied, the panel outlines are made into mesh objects and subdivided using the Delaunay algorithm, as shown in Figure 19.9. This algorithm uses random triangulation and divides the triangles into roughly equal shapes. This helps keep the cloth from folding along common lines caused by regular patterns. You can alter the number of polygons in the subdivided mesh using the Density value. If the Auto Mesh option is disabled, then you can update the density change using the Mesh It button. The Preserve option maintains the 3D shape of the object. If Preserve is disabled, then the panel is made flat.

Figure 19.9: The Garment Maker modifier uses the Delaunay algorithm for subdividing cloth meshes

The next step is to position the panels so they surround the model that they will be draped over. The subject that is to receive the clothes can be selected by clicking the Figure button in the Main Parameters rollout. After an object is selected, clicking the Mark Points on Figure button makes a small figure outline appear in the upper-left corner of the viewport, as shown in Figure 19.10. This figure outline has markers corresponding to the chest, neck, pelvis, shoulder, and wrists. Dragging over the body of the character lets you mark corresponding locations on the character.

Figure 19.10: The figure outline lets you identify corresponding body markers on the character model for positioning cloth panels

After body parts are marked, you can select a cloth panel and use the Panel Position buttons in the Panel rollout to position the various cloth panels around the body. The Panel Position buttons include Front Center, Front Right, Back Center, Right Arm, etc. You also can position the panels manually.

The Garment Maker modifier has three subobjects: Curves, Panels, and Seams. With the panels in place, you can stitch seams between the panels using the Curves subobject mode for flat drawn panels or with the Seams subobject mode for panels that are positioned about a model. Each seam edge should be relatively the same length. The Seam Tolerance value sets how far apart the two edges can deviate. For each seam, you can set a Crease Angle and Strength. The Sewing Stiffness value determines the strength that the seams are pulled together.

After the seams are defined, you can apply the Modifiers Cloth Cloth modifier to pull the panels together and simulate the cloth's motion.

Creating cloth from geometry objects

Any geometry object can be made into a cloth object using the Cloth modifier available by selecting the Modifiers Cloth Cloth menu command. Although the modifier is added to the object, it is set to Inactive by default. To activate the cloth, you need to open the Object Properties dialog box, shown in Figure 19.11.

Figure 19.11: The Object Properties dialog box includes all the parameters for the cloth and collision objects

The list at the left holds all the objects that are involved in the cloth simulation. New objects can be added to the list using the Add Objects button. Each object can be set to Inactive, Cloth, or Collision Object, and properties can be set for each type. For cloth, the properties include Bend, Stretch, Shear, Density, Thickness, Friction, and Scale values. Defined cloth settings can be saved and recalled. Cloth property files are saved using the .STI file extension. Max also includes a sizable list of presets in a drop-down list, including Burlap, Cashmere, Cotton, Flannel, Rubber, Satin, Silk, Terrycloth, and Wool, among others.

In addition to objects added to the scene, a cloth simulation also can include forces. The Cloth Forces button opens a dialog box where you can select which forces in the scene can be added to the cloth simulation. Gravity is added by default automatically to the simulation. You can set the Gravity value in the Simulation Parameters rollout along with several other parameters, including the Start and End Frames.

With all the objects and forces added, click the Simulate Local button to set the initial state of the cloth simulation. This drapes the cloth over the scene objects and pulls all defined seams from the Garment Maker modifier together. Sometimes the Simulate Local button moves the cloth panels together too fast, so you can use the Simulate Local (damped) button to add lots of damping to the scene to prevent problems from panels moving too fast.

Tutorial: Clothing a 3D model

If you've ever want to design and outfit a set of models with a custom-made line of clothing, here's your chance. Using Garment Maker and the Cloth modifiers, we outfit our 3D model with a set of clothes. Watch for this new line next spring at your local retailers. This excellent female character was supplied by Zygote Media.

To create and apply a set of clothes to a 3D character, follow these steps:

1. Open the  Zygote woman with clothes.max file from the Chap 19 directory on the DVD.

2. Select the Create Shapes Line menu command, and draw in the Top viewport the front outline of a simple tank top and a simple skirt. Make sure the panels are closed splines.

3. Select the Tools Mirror menu command, and create mirrored copies of the clothes for the back side. Then convert one of the panels to an Editable Spline, and attach all the other panels together into a single object. In Vertex subobject mode, select all the corner vertices in all panels and click the Break button.

4. With the clothes selected, choose the Modifiers Cloth Garment Maker modifier. This automatically subdivides all the cloth panels into multiple polygons.

5. In the Main Parameters rollout, click the Figure button and select the female character. Then click the Mark Points on Figure button. A small figure appears in the upper-left corner of each viewport with the upper chest area marked in red. Drag the cursor over the character until the matching upper chest area is located, and click. Repeat for all the marked positions. When all points are marked, click the Mark Points on Figure button again to exit marking mode.

6. In the Modify panel, select the Panels subobject mode and choose the tank top's front panel. Select the Top at Neck level, and click the Front Center button. This places the tank top's front in front of the character. Repeat the placement for the other panels. If the placement isn't correct, manually move the panels until they are in front of and behind the character, as shown in Figure 19.12.

   Figure 19.12: Using figure markers, you can approximate where the clothes are positioned on a character

7. In the Modify panel, select the Seams subobject mode. In the Front viewport, select two edges that should be connected and click the Create Seam button. Repeat this for all seams including the sides of the skirt and shirt and the top of the shirt. Connecting lines are drawn between both sides of the seam. If the seam boundaries are crossed, then click the Reverse Seam button.

8. With the seams defined, select Modifiers Cloth Cloth to apply the Cloth modifier. In the Object rollout, click the Object Properties button. In the Object Properties dialog box, select the clothes object and enable the Cloth option. Then click the Add Objects button, select the character mesh, and mark it as a Collision Object. Set the Offset value for the clothes to 0.3, and close the Object Properties dialog box.

9. Click the Simulate Local button. The cloth seams are pulled together, and the clothes are draped over the character.

Figure 19.13 shows the female character in a simple gown.

Figure 19.13: The Simulate Local button causes the clothes to be draped over the body