July 13, 2011, 8:17 p.m.
posted by nuclear
Modifiers remain ghosted out and unselectable until you have an object or model targeted in a scene. You’ll probably find that you gravitate towards one of the three Modifier selection methods more than the other two. I enjoy using the Modifier icons in the Tab Panel most. Most Modifiers can be applied to any of the following:
Any object/model that has a polygonal mesh or Patch surface (a Patch surface is defined by three-sided polygons).
Grouped objects. Please remember that Modifiers reference the Pivot Point of singular, multiple, or Grouped objects.
Any Instanced Clone source object. The Modifier effect is applied to all Instanced Clones in the chain if either the source or any clone is modified.
Any Referenced clone in a cloned chain, without being applied to any other clone in the chain or to the source object.
These are the most common Modifiers applied to entire polygon meshes and patch objects, either in whole or in part (the next chapter looks at Modifier effects for just part of the mesh, or sub-selections). Using combinations of these Modifiers is a quick way to model complex forms.
Although you can bend any selected object with this Modifier, it works best when the targeted object is elongated and thin. Make sure that the object has a fairly heavy polygon count to get a smooth-looking bend. A cylinder, for instance, should have at least 15 height segments. After you select the Bend Modifier with an object selected, its Command Panel appears. See Figure.
The basic commands are pretty self-explanatory. Bend Angle and Direction can be any values you like. A 360-degree Bend Angle, for instance, attempts to bend the object into a circle. Pivot Point position makes all the difference. You can select the Bend Axis in real time, watching a viewport to see the results. You also have to make sure that the object has a dense enough polygon mesh to create a smooth bend. Don’t tamper with limits until you get some experience with what the other values do. Figure provides an example.
The cylinder in Figure has 15 Height Segments for a smoother bend, and was created in the Top Viewport. Left to right at the top, the Bend Angle was set to 90, 180, and 360 degrees. The Z-axis was used in all cases. The bottom figure uses the same cylinder with a 360-degree angle on the Z-axis, but the Bend Modifier was used twice with the same settings to create this complex object.
The Taper Modifier makes one end of an object’s axis smaller or larger than the other end. An example would be a Cone, which is simply a tapered cylinder.
Amount of the Taper ranges from -10 to 10. The Curve value (also -10 to 10) alters the way the Taper is applied. Taper Axis has a Primary option and an additional Effect axis. Combining the two varies the result. Choosing Symmetry forces a symmetrical parameter on the object.
Skew creates the effect witnessed by a stack of books leaning towards one side.
The two most important values in this panel are Amount and Skew Axis. The Amount can be a negative or positive value, setting the “leaning” one way or the other, while the selected axis takes on the skew.
The Twist Modifier does exactly what you’d expect it to do. It twists the object on any selected axis. Angle and Axis are the two core parameters set in the Twist Modifier’s Command Panel. As with most of the other Modifiers, a denser polygon mesh allows for the creation of smoother Twist effects. See Figure.
The Stretch Modifier does not perform the same action as basic scaling on an axis. Instead, Stretch pinches the object as well. The Twist Modifier stretches the object in two directions from its center. Stretch Amount, Axis, and Amplify are the main parameter controls. Amplify sets the extent of the pinching effect. See Figure.
Noise creates irregular surface bumps on a targeted object, roughening it up (see Figure). In this way, a sphere can be modified to look like a planetoid with an irregular surface. Noise works best when the mesh is dense; it rearranges the object’s surface geometry. You can set the roughness of the noise, as well as its strength, on the X-, Y-, and Z-axis.
Figure: This object started out as a dense sphere, with 128 segments. A Noise Modifier was applied with a Scale of 335, Roughness set to 1, and a strength of 11 on the X, Y, and Z-axis. Could it be a scoop of ice cream with nuts?
The Wave Modifier creates a linear wave from the vertical axis onto the X-axis of the object. You can control the Amplitude (strength) and the Wavelength in the Command Panel. See Figure.
Melt is normally an animation Modifier; it can cause any selected object to melt into a puddle over a specified time. You can also use it to create interesting object modifications if you choose Collapse All afterward. You can control the Amount (strength) of the melt, the Percentage of the melt (0 to 100), the axis of the effect, and whether your object melts like Ice, Glass, Jelly, Plastic, or a custom material. Figure illustrates some possibilities.
Figure: A Melt targeted to a sphere, with Amount set to 85 and a Percentage of 100, melting just like (left to right) Ice, Glass, Jelly, and Plastic.
The Spherify Modifier forces the selected object to become spherical, as much as possible. It has one setting: Percentage (0 to 100). Figure shows several degrees of this setting.
Using the Ripple Modifier causes the same effect as watching a pond after a rock is thrown in. You control Amplitude and Wavelength in the Command Panel.
FFD modification is like working with clay to form objects. Free-Form Deformation is a bit more complex to work with than most of the other Modifiers. The following general steps illustrate a typical instance:
Choose either Box FFD or Cylinder FFD for the targeted object.
FFD creates a cage made up of a lattice of points around your object. The cage can remain box-like or cylindrical, or it can be forced to conform exactly to the shape of your object.
To shape the cage to your object, click Conform to Shape in the FFD Command Panel.
Set the number of XYZ control points in the FFD lattice by clicking Set Number of Points in the Command Panel.
I find it best to use at least eight points on each axis.
Double-click the FFD option in the Modifiers List.
Use the Select and Move tool to move lattice points.
The object responds by smoothly assuming a new, curved shape.
You can use FFD to create all manner of unique forms, including organic models like heads and other body parts, but it takes practice. See Figure.
As you work more with Modifiers, you’ll have favorites. Lattice is one of mine. Other 3D software might call this Modifier Sticks-and-Balls. The “sticks” are called Struts in the Lattice Modifier; they refer to the polygonal edges of the target object. The “balls” are called Joints, and correspond to the vertices of the polygons. You can control the number of sides and the size of the Struts, and the type (Tetrahedron, Octahedron, or Icosahedron) and size of the Joints. The result is a skeletal version of your model that looks like something under construction. Figure shows some nifty examples.
Figure: A variety of boxes targeted by the Lattice Modifier with different Strut and Joint parameters.
You just can’t get along without Optimize. Optimization alters the polygon count of an object. It’s especially vital when you are creating models for games, where the polygon count has to be kept low, while at the same time keeping the general form of the targeted object. The main control in the Optimize Modifier’s Command Panel is Face Threshold. Lower settings (0 being the lowest) affect the number of polygons least, while higher settings start to decrease the number of polygons. The values affect the targeted object according to its geometry, so you can’t use any single value for all objects. Higher settings can deform the geometry of the object severely, so use with care. Figure shows a typically Optimized result.
Figure: The original polygon count of a sphere with 32 segments is on the left. The second figure shows an optimization with the threshold set to 7, while the right-hand image displays what happens when the Optimize threshold is set to 12.