Polygonal Modeling 2

Polygonal Text Settings
When you create polygonal text, Maya provides option that you can set to display and create your text for subsequent polygonal-type editing.

Triangles

Three sided polygons are created. This is the default.

Tessellation Methods

Standard fit

This is the default tessellation method. It is adaptive tessellation, meaning that following option is used to determine when to stop the tessellation. The tessellation stops at the fractional tolerance value you set. If there is an edge shorter than the Minimal Edge Length, the tessellation stops on that edge. If the surface is flat enough with in the edge, the tessellation stops here.

General

Set the tessellation method to General to display the following options. Unless Use chord height or use chord height ratio is turned on, a uniform tessellation is performed. Each span is split into a number of polygons depending on the number U and V values you set.

Count

Set the tessellation method to Count to display the Following slider. Count slider is used to determine how many polygons the surface can be tessellated into.

Control points

This tessellation method converts the Nurbs model to polygons while matching the CVs of the original Nurbs surface. There are no other options for this operation.
Extruding
You can pull faces and edges out from polygonal objects using the Extrude Face and Extrude Edge commands.

Extruding Faces

You can extrude faces either interactively or directly through the option window. Select Edit Polygons > Extrude Face ,set whatever option you need and click the Extrude Face button.

• If you want to extrude all the faces of an object, marquee-select the whole object to highlight the faces.
• If you want to extrude certain areas  of an object, shift-or Ctrl-click to select those face only.
• If you want to extrude ,duplicate or extract multiple faces together, turn on polygons > Tool options >Keep Faces Together.

you are not happy with results, select Undo from the Edit menu, change the  Extrusions settings in the channel Box or Attribute Editor and press Enter.

Extruding Edges

You can extrude edges either interactively or directly through the option window. If you prefer to set the options first and then extrude the edges, Select Edit Polygons > Extrude Face.
Duplicating Faces
You can duplicate and transform faces interactively or directly through the option window.  Select the faces of the object you want to duplicate. Press the right mouse button and select Face or press F11.

• If you want to duplicate all the faces of an object, marquee-select the whole object to highlight the faces.
• If you want to duplicate certain areas  of an object, click to select those face only.

You can also Duplicate Faces through Edit Polygons > Duplicate Face.
Extracting Faces
While Extracting ,Maya disconnects the selected Faces from the original shape, by duplicating the appropriate edges and vertices. The extracted faces become their own shell with in the object. This is the another way to make holes in the object while retaining their original faces.
Seperating the extracted faces creates distinct polygons out of the faces and the original object.
To extract Faces

• Select the face of the object you want to extract. Press the right mouse button and select Face from the marking menu or press F11,then shift or Ctrl-Click to select the faces.
• Select edit Polygons > Extract. The selected Faces are extracted.

Fig4-4 Extracting faces
Smoothing Polygons
There are three ways to smooth polygons.

• Using Polygons > smooth.
• Using Polygons >Average vertices.
• Using the smooth operation of the sculpt polygons Tool to average the values of painted vertices to produce a smoother surface.

Polygon Selection
With Edit Polygons > Selection menu, you can constrain the selection of components to a specified area of a polygonal model and perform operations on those components in that specified area only without disturbing the rest of the model.
Select Edit Polygon > Selection >Grow Selection Region to increase the number of components you initially selected.

Selecting Boundaries

You use Edit Polygons >Selection >Select Selection Boundary to define the boundary of the current selection region. It is a quick way to select the boundaries of whatever is currently selected.

Selection a band of edges

Use Edit Polygons > Selection > Select Contiguous Edges to select a contiguous band of edges around model. With this you can select one edge, choose select Contiguous Edges, and it will select the rest of the edges  in the center automatically.

Max 2d Angle ,Max 3d Angle

These settings determine how far the selection continues based on the angles between edges. The 2d angle refers to angle made by the surface topology, regardless of the surface's shape. The 3d angle refers to angles made by the surface's shape, as measured in world or local space.

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Texturing and Shading 1

Materials are a critical part of creating attractive images and animation in a 3D program. Materials interact with lights, so lighting drives some material choices; for example, if your overall lighting is bright, you might need to make your scene materials somewhat more matte and light absorbing so that they don't blow out when hit by bright lights.
What do we mean by "materials"? It's a catch-all term to describe all aspects of what a surface looks like. At first glance, beginners usually notice the surface color—red, wood brown, metallic silver. To an artist, however, there are many other factors: An object isn't just metallic silver, for example—it's a mirrored smooth finish that relies on the reflected surroundings for its appearance. In addition to factors of color, shine, and reflection, Maya also considers transparency, incandescence, translucency, refraction, bumpiness, and many other user-controlled parameters. Attention to these details gives your rendered results more subtlety and complexity.
Hypershade
Maya's Hypershade is one of the first and most important areas you should take the time to explore. It provides a quick and easy way to create,edit, and connect rendering nodes, such as textures, materials, lights, rendering utilities and special effects.
Hypershade uses a free-form approach to material design. Swatches connect to one another to create effects; for example, a brick image might connect to the Bump attribute of a material to create bumps in the pattern of bricks. Hypershade also doubles as a kind of browser so that you can view and select existing scene lights, cameras, materials, and other elements.
To open Hypershade, choose Window > Rendering Editors > Hypershade (hotkey: Alt+h).

Fig 5-1 Hypershade
Hypershade displays each node as an icon, sometimes called a swatch, that represents the characteristics of the node. When you edit a node's attributes or assign textures or special effects, that swatch updates in hypershade.

Create Bar

At the left is the Create Bar, which displays all the material types you can create for a selected category. Simply click on a type to create that item in the Work Area. To select a category, click the down arrow on the Create Bar; the options are Materials, Textures, Lights, Utilities, and All Nodes.

Tab Panels

The top tab shows existing materials, and the bottom tab is used to create and edit materials. After you become familiar with Hypershade, you can customize the tabs to your liking and even add Work Area tabs to simultaneously edit several materials.

Top Tab

This  area displays all the elements that are already part of the current scene file in these tabs: Materials, Textures, Utilities, Lights, Cameras, and Projects. In this tab, you can duplicate, edit, select objects assigned to shading groups, link lights, import and export materials, and a number of other functions

Bottom Tab

This  area is usually used as the Work Area—the assembly point for new materials.

Basic Material Types

Lambert

Lambert is a flat material type that yields a smooth look without specular highlights. It calculates without taking into account surface or reflectivity, which gives a matte, chalk-like appearance. Lambert material is ideal for surfaces that don't have highlights: pottery, chalk, matte paint, and so forth. By default, any newly created object is assigned the Lambert shader.

Phong

The Phong material takes into account specular reflectivity to create highlights across an object surface. The algorithm can be customized for surfaces such as plastic, porcelain, and glazed ceramic.

PhongE

PhongE is a faster rendering version of Phong that yields somewhat softer highlights than Phong.

Blinn

The Blinn material calculates highlights on surfaces similarly to Phong; however, Blinn can achieve a more accurate representation of the soft tinted highlights you see on metallic surfaces. Because Blinn is a versatile material type and doesn't cause flickering with bump maps.

Anisotropic

The Anisotropic material type stretches highlights and rotates them based on the viewer's position. Anisotropic materials are ideal for materials such as hair, feathers, brushed metal, and satin.

Ramp Shader

The Ramp Shader material consists of built-in ramp graphs to offer more advanced control and simplify the shader network.

Ocean Shader

The Ocean Shader material has several items in the shader's attributes that control how the material behaves over time, and it has graphs to add detail to the base shader. Attributes include Wave Speed, Wave Height, Wave Turbulence, and Wave Peaking.

Layered Shader

The Layered Shader lets you combine several materials to create a more complex material.

Shading Map

The Shading Map material is primarily designed to let you get a "cel" look in 3D, like typical animated cartoons.

Surface Shader

The Surface Shader is used when you want to control a material's color, transparency, and glow with something else in Maya.

Use Background

The Use Background shader cuts a "hole" in the image's alpha channel where objects with the material appear. This material is useful for combining separately rendered images in a compositing program to create the final results.
Material Settings
To edit material settings, double-click on any material in Hypershade's top or bottom tabs. Usually, you create a Blinn material in the Work Area of the bottom tab panel, and then double-click it to edit it in the Attribute Editor.

Fig 5_2 Material settings in the attribute editor
Notice the material name at the top of the Attribute Editor, which Maya sets to blinn1 for a default starting name. Maya increments the number if you create more Blinn materials. Next is the Common Material Attributes section, followed by the Specular Shading section. These two sections, displayed by default, are used the most in material editing.

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Texturing and Shading 2

Color
The default material color.

Transparency

If the transparency value is 0(black),the surface is totally opaque; if the transparency value is 1(white),the surface is totally transparent. If you change transparency from the default black ,the background of the material's hypershade swatch becomes a checked pattern .This is not a visual aid and is not rendered.

Ambient Color

Uses Black by default. As the ambient color becomes lighter, it affect's the material's color by lightening it and blending the two colors.

Incandescence

The color and the brightness of light that a material appears to be emitting. The default color value is 0.

Bump Mapping

Makes the surface appear more rough or bumpy by altering surface normals according to the intensity of the pixels in the bump map texture. A bump map does not actually alter the surface.

Diffuse

Gives the material ability to reflect light in all directions. The diffuse value acts like a scaling factor applied to the color setting-the higher the diffuse value, the closer the actual surface is to the color setting.

Translucence

Gives the material the ability to transmit and diffuse light.  Light falling on a translucent surface is first absorbed beneath the surface and then diffused in all directions. The slider range is 0 to 1.
Surface Material Attributes

Specular color

The color of shiny highlights on the surface. A black specular color produces no surface highlights. The default color value is 0.5.

Reflectivity

Gives the surface the ability to reflect its surroundings or the reflected color. The default color value is 0.5.

Reflected color

Represents the color of light reflected from the material. This can be used to tint a reflection.

Surface Material

Fig 5-3 Surface Materials

Anisotropic

Represents surfaces with grooves, such as cd or feathers etc. Anisotropic material (such as Phong or Blinn)reflects specular light  identically in all directions.If you spin an isotropic sphere, its specular   highlight remains still.

Roughness

Determines the overall roughness of the surface. The range is 0.01 to 1.0.The default is 0.7.Smaller values correspond to smoother surfaces and the specular highlights are more concentrated.

Fresnel Index

A fresnel is a flat lens consisting of a number of concentric rings that reduces spherical abnormalities. The Fresnel index for water is 1.33.Value range from 1.0 to 20.0.

Anisotropic Reflectivity

If on, Maya automatically calculates Reflectivity as a fraction of roughness. Reflectivity is on by default.
Blinn Attributes
Color The base color of the surface.
Transparency Adjusts the surface opacity. You can use colors to create a tinted glass effect.
Ambient Color Adds to and blends with the color value.
Incandescence A simulation of emitted light. At low values, it tints and self-illuminates the material, and at high values, it overtakes the material's color and becomes self-illuminated.
Diffuse By default, it's set to 0.8, which dulls down the color value you've set.
Translucence A special effect in which light is absorbed and scattered as it passes through an object, useful for simulating materials such as frosted glass.
Translucence Focus Controls how light scatters from the surface.
Eccentricity The width of the highlight, simulating how polished or rough the surface appears.
Specular Roll Off The brightness/intensity of the highlight.
Specular Color The color of the highlight; usually set to white or a gray value.
Reflectivity The strength of reflections on the object. Reflections can be raytraced or use texture maps.
Reflected Color For Blinn, the color swatch and slider have no effect. However, when a texture map is applied, it appears to be reflected by the material.
Lambert
Represents matte surface(such as chalk,matte paint,unpolished surfaces) with no specular highlights. The initial shading group uses a lambert material.
Layered Shader Attributes
Represents a single surface material composed of several  different surface materials layered on top of one another.
Transparency
By default the material is semi-transparent.

Compositing Flag

Composites the layers using a layered shader or layered texture mode.

Hardware color

Helps you distinguish the objects assigned to a layered shader in the views.
Phong Attributes
Represents glassy or glossy surfaces with a hard specular highlight.

Cosine power

This feature is available to the phong material. Controls the size of shiny highlights on the surface. The default value is 20.
Phong E Attributes
A simpler version of the phong material. The specular highlights on the Phong E surfaces are softer than those on Phong Surfaces and Phong E surfaces render faster than Phong surfaces.

Roughness

Controls the specularity focus.

Highlight Size

Controls the amount of specular highlight.

Whiteness

Controls the specular highlight color. The default value is white. You can also map a texture to this value.

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Texturing and Shading 3

Shading Map Attributes
Represents a color map you apply to surfaces after they are rendered.The shading map material is useful for creating non-photorealistic effects(cartoon shading)or to highlight threshold values in a rendered image.

Shading Map Color

Defines the color of the material. The default is gray.

Shader

You can map any material to the shading Map material.
Surfaces Shader Attributes
A wrapper node, meaning you can connect any keyable attribute to this shading group and then connect the shading group to an object.

Out color

The color of the material .The default is black.

Out Transparency

The transparency of the material. The default is black.

Out Glow Color

The glow color of the material. The default is black, without glow.
Use Background
You use it to set the object's Matte channel to 1 or 0, or create a matte for shadows and reflections on the surface. This material applies the same color as the objects in the background image to stand -in-surfaces.

Attributes

Adjust the Use Background material's to the light ,shadows, reflections and the geometry placement in the scene.
Texture Mapping
Normally, a texture refers to applying a 2D image around a 3D surface, rather like wallpapering a curvy surface. Because a 2D image can be stretched, wrapped, and projected onto a surface in many different ways.

Mapping Coordinates

Mapping coordinates, also known as UV coordinates. For NURBS, parametric mapping is inherent to the surface and this is typically what's used. Parametric mapping is the 0 to 1 coordinate system that NURBS uses to map textures across its surfaces. It makes sure that the textures stay mapped to the surface like a decal, even if the geometry is deformed.
For polygon surfaces, mapping is normally applied by projecting 2D maps across the 3D surface in one of several ways: planar, cylindrical, spherical, and a special method called automatic mapping.

Fig 5-4 Mapping projection
Procedural Maps
In addition to applying an image or movie to a surface, Maya has other texture types called procedural textures. Many patterns, such as bricks, tiles, and gradients, are so repetitive that they can easily be represented by an equation. By using special forms of seemingly random values, many natural effects can be simulated mathematically: Marble, leather, water, granite, and many other complex and random textures are included with Maya as procedurals.
Maya's procedural textures come in two varieties: 2D and 3D. You can think of the 2D procedurals as a calculated form of a bitmap.When 3D procedurals are applied, however, they exist throughout 3D space, and object surfaces define where you see the texture. It's like carving the object from a block of the material.Procedural textures have several benefits. Because they are formula based, their parameters can be adjusted to instantly synthesize all kinds of different effects.

2D Procedurals

Maya's 2D procedurals can be divided into two categories: regular patterns and noise patterns. The regular patterns include Grid, Checker, Bulge, Cloth, and Ramp. With these patterns, you can create tiles, bricks, and many other man-made repeating effects. Noise patterns include Fractal, Mountain, Noise, and Water. These psuedorandom textures are excellent for creating the complex "dirty" surfaces common in nature.

3D Procedurals

All the 3D procedurals but snow are random types. Some, such as wood and marble, clearly imitate nature. However, all are excellent for synthesizing random effects.
Assigning material to surfaces
The following lists a few quick ways to assign a material to a surface.

• In the view,select the surface to which you want to assign the material.
• From Hypershade, MMB-drag the material swatch over the selected surfaces.

or

• In the view ,shift-select the object to which you want to assign the material and in hypershade,click the material swatch.
• While the cursor is over the material swatch in hypershade,RMB -click-drag to select assign material to selection from the pop-up menu.

or

• MMB-drag and drop a Hypershade swatch onto an object in the IPR Render view.

To apply a material to several surfaces from with Hypershade

• Select the surfaces in a view.
• In Hypershade,RMB-click over the material swatch and select Assign material to selection from the pop-up menu.

To apply a material to a group of faces on a polygonal surface

• Select the surface.
• Press the RMB while over the surface,select face from the marking menu,then choose the select by component type icon.
• Select the face you want to map.
• While the faces are highlighted in the view, in hypershade,LMB-shift-click over the material swatch you want and press theRMB and select  Assign material to selection from the pop-up menu.

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Cameras and Lighting 1

mWhen Maya starts, you have four cameras by default: front, side, top and perspective. Three of them are orthographic—flat, non-perspective views—and have visible icons you can use to translate or rotate the camera. The icon for the perspective camera is, by default, invisible. These four cameras are utility views that assist you in modeling and laying out your scene. When you're ready to pick the final rendered viewpoint of your scene, you should create a scene camera. If you're shooting a series of stills, you can create many cameras, one for each shot.
The camera placement determines exactly what will be seen and is used to frame specific portions of the scene, in the same way illustrators or photographers use composition to frame certain elements in their paintings and drawings. Other key variables for cameras are focal length, rotation (orientation), and angle of view. Focal length is directly linked to angle of view; if one goes up, the other goes down. With angle of view, as the angle of the lens widens, you must move the camera closer to the subject to keep it at the same relative size in the frame. The wider the angle, the higher the value for the Angle of View setting.
Creating Cameras
Create > Cameras > Camera 
There are three types of perspective cameras in Maya. As with Maya's lights, you can change a camera to any other camera type in the Attribute Editor.
Camera
With this camera type, you see only the camera icon. In general, because this camera freely rotates and loses track of its "up" vector, you should use it only when you're linking the camera to another object for movement and animation, or when you're placing a camera in one fixed spot.

Camera and Aim

This camera includes a camera target and an aim handle for adjusting the camera target. In addition, this camera automatically stays level in relation to the horizon, so it's the one you'll use most often. You can make this camera roll if you want, but by default, it stays level except at extreme straight-up or straight-down orientations.

Camera, Aim and Up

This camera type includes two handles: the aim handle, described for Camera and Aim, and an up handle for banking (leveling) the camera. This camera type is useful when you want to bank the camera during your animation.

Fig6-1 Camera types
Camera Settings
These are the key settings for cameras under the Camera Attributes section:

Fig 6_2  Camera Attributes
Controls In this drop-down list, you can quickly select the camera type you want.
Angle of View and Focal Length Controls the amount of perspective exaggeration. Raising the Angle of View attribute lowers the Focal Length attribute.
Camera Scale You can change the camera size in relation to your scene, which affects scene objects when you render. Camera Scale is like a multiplier for the Angle of View setting. For example, decreasing Camera Scale to .5 halves the camera's view area, but makes objects in the scene look twice as large.
Clip Planes Only objects located within the values specified for the camera's clip planes appear in the scene. If distant objects are not showing up in your scene, raise the Far Clip Plane value. If nearby objects seem to be appearing in cross-section or not appearing at all, lower the Near Clip Plane value.
Depth of Field Enable distance blur with this attribute. It can be a render-intensive effect, but yields a nice cinematic result because objects close to and far away from the focus point are progressively blurred.
Background Color The background fill color for images rendered from this camera; you can also use this section of the Attribute Editor to add an image or shader as the background.
Orthographic Views Switches the camera to an orthographic view. You can create perspective cameras, rotate them into position, and then set them to orthographic to get a "flat" view for projecting textures onto an object.
Animating the Camera
When you first begin animating the camera, it helps to follow the rules of videography, such as avoiding jarring camera motions—rapid pans, zooms, or rotations of the camera. In addition, you should usually give the camera the impression of having mass. The virtual camera, by default, starts and stops moving instantly, which looks unrealistic and abrupt to viewers. To avoid this problem, adjust the tangents for the camera position's start and stop keys in the Graph Editor so that motion begins and ends gradually . Do the same for the camera's aim point keys and any other animated camera attributes

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Cameras and Lighting 2

Lighting
Lighting design in Maya is similar, but not completely identical, to how it's done in the real world. You have several types of lights to choose from in Maya; each one has unique attributes and benefits, and you'll learn what each type is best used for. When you know how to work with lights, scenes that once rendered dull can take on a new radiance. Most of the time you're trying to get a realistic effect with your lights, and Maya's virtual lights do not work in a realistic way—in particular, beams of light within Maya do not reflect off surfaces. In the real world, even a single light source can fully illuminate a room because its beams reflect from surfaces to reach areas under desks and shelves .In Maya, however, those areas are completely dark, so one solution is to simulate diffuse reflection by adding many low-level lights.
Creatively, lighting defines the scene's mood. If you're trying to create a chilling, spooky effect, you'll probably want dim lighting in the scene. For a feeling of suspense, you might decide to have flickering lights. Lighting in a scene creates the shadows, influences colors, and directly affects the appearance of materials. The results of a well-lit scene are worth the effort and time. Skillful lighting creates contrast between objects, enhances the colors in your scene, and gives you more control over the scene's shading.
Light Types
Several different lights are available in Maya 5, each with its own properties and uses: Ambient, Directional, Point, Spot, Area, and Volume lights.

Fig 6-3 Types of Lights

Ambient Light

The Ambient light type creates light on all surfaces. It is in no way comparable to the real-world ambient light that creates the diffuse reflection of surfaces. Instead, it's a kind of auto-self-illumination that brightens all parts of your scene equally. For this reason, this light type should be used sparingly or for special cases only, or it can give your scene a washed-out or flat appearance. Maya's Ambient lights can also cast shadows. In essence, these features allow you to use Ambient lights as though they were Point lights, with a variable "shine everywhere" setting. This setting is called Ambient Shade, and the light behaves more like a Point light as this value approaches 1.
Directional Light
The Directional light is the default light used when you create a new scene. This light is good for emulating rays of light coming from the sun and does a fine job of lighting the entire scene instead of just targeted areas.
Point Light
Unlike the Directional light, which has light rays that are parallel to each other, a Point light casts rays of light evenly in every direction from a point. Point lights are sometimes used for simulating omni directional light sources, such as light bulbs.
Spot Light
The Spot light's area of illumination is defined by a cone, and within the cone's specified range, light is cast evenly. Starting from an infinitely small point in space, a Spot light spreads as it moves farther from the origin. Spot lights are useful when you're trying to create beams of light from, for example, a prison watch tower, a lighthouse, and so forth.

Fig 6-4 Attribute Editor

Area Light

With Area lights, you can have a source of light that doesn't just come from an infinitely small point in space. The Area light emits rays from a rectangular area in space and can be scaled larger or smaller. This makes an Area light a great choice when you're looking for realistic lighting, but be forewarned that it takes longer to render. By using an Area light, you'll get shadows that soften as they're cast farther from the shadow-casting object. Maya uses only two-dimensional flat Area lights that are rectangular.
Volume Light
Volume lights have a visible range of influence that allows you to see exactly where the light dies out. By default, the light intensity falls off linearly from the light's center point to the visible outer boundary. This type of light is ideal for interior lighting, because you usually want lights to fade with distance if they're primary sources of light.

Fig 6-5 Light Attributes

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Cameras and Lighting 3

Light Attributes
Intensity
A light's Intensity attribute controls the brightness of the source. You can set it to any value, positive or negative. If the intensity is raised, more light is emitted from the source . Usually, you set the value between 0 and 1 for a medium-intensity fill light. For sunlight effects, you might go as high as 1.5 or so. With Decay Rate added , the light's Intensity value might need to be set much higher because the strength can fall off rapidly with distance. All Maya's default lights have no decay rate  and illuminate objects at full intensity, regardless of distance.You can also use negative values for the Intensity attribute. By setting a negative value, the light actually "absorbs" other light. If you have an area of the scene that you want to be pitch-black but have light illuminating it, you can use a light with a negative Intensity setting to help eliminate the problem.

Illuminates by Default

By default, lights automatically illuminate all objects in the scene. When you disable the Illuminates by Default check box, the light is removed from the default Light Set and affects only objects it's linked to. Light linking is handled in the Relationship Editor for lights (Window > Relationship Editors > Light Linking). In this dialog box, you can select a light and then choose which objects it illuminates .

Fig 6_6 Relationship Editor

Emit Diffuse and Emit Specular

The Emit Diffuse and Emit Specular attributes are not available with Ambient lights. Emit Diffuse is particularly useful for creating soft fill lights to simulate light reflection; you need to disable the Emit Specular attribute so that no highlights are generated. Emit Specular can also be useful for lighting metal objects (such as chrome logos) when you want to add specular highlights to the metal without brightening other areas.

Color

Each light can have its own color assigned, and modifying the color of a light follows the same procedure and uses the same Color Chooser dialog box you see when modifying color for a material. You can also map textures to a light's color, causing the light to project the texture like a slide projector. Or if you animate the texture variables or use a movie as the source, the light acts as a movie projector.

Decay Rate

Specific to Spot, Area, and Point lights, this attribute determines the rate at which the light intensity fades (decreases) at a distance. Several types of decay are available in the Attribute Editor's Decay Rate list box.
No Decay  The light does not diminish with distance; it reaches all objects in the scene.
Linear The intensity of emitted light decreases at a constant (linear) rate as distance from the light source increases. Linear decay is the most frequently used type because it's easier to control; you don't need to raise the light's Intensity attribute to enormously high values to compensate.
Quadratic A physically accurate mode of decay, also known as inverse square. Quadratic decay is determined by proportionally decreasing the light intensity along the square of the distance. Light intensity generally must be raised substantially with this mode.
Cubic  Decreases the intensity of light faster than the rate seen in reality. Cubic Decay is evaluated by a decrease in intensity that's relatively proportional to the cube of the distance. The lit area falls off almost instantly with Cubic Decay. This type of decay can be used to create a lit area that seems as though it's burning within surrounding darkness.
IPR rendering is a helpful tool for interactively adjusting light decay; it's hard to visualize otherwise.

Shadows

Shadows in Maya can be turned on or off. The default setting for lights is to have the shadow set to off. Surfaces illuminated by the non-shadow–casting light are still shaded by it, but won't cast shadows onto other surfaces. That means the part of an object that's exposed to light is illuminated, and the object's opposite side fades to a darker tone. An object's shadow can identify its size, position, and orientation in space, so by adding shadows to your scene, you can more clearly define the spatial relationships between objects. Without shadows in a scene, the render looks flat and lacks depth. Shadows add depth and realism to the scene, especially indoor scenes.
Shadows tend to wash each other out as you add more shadow-casting lights that illuminate the same area. With Maya, you have a lot of control over the way shadows are cast in a scene, which can help you reduce render times, add contrast to your renderings, and create a better-looking overall result. There are two types of shadows in Maya: depth map and ray traced shadows.
Depth Map Shadows
Depth map shadows are produced through an image map. The depth map is calculated immediately before the actual render takes place. Using calculations for the distance of light to a specific point on an object, depth information is stored in the map and then passed on to the rendering engine to produce a "simulated" shadow effect. The depth map tells the rendering engine which areas of the scene are illuminated by light
Depth map shadows usually give good results without having to worry about a huge increase in render time. They are usually slightly softer, too, which is more natural than harsh-edged ray traced shadows. If you want, you can achieve almost the same level of sharpness as ray traced shadows. Depth map shadows work in a unique way for Point, Ambient, and Area lights: Because a square bitmap is required to create the shadow, and these light types cast light in all directions, they must create multiple maps to cover the area. Maya uses cubic shadow maps for these light types—that is, six depth maps are cast for the six sides of a cube. This process requires six times the RAM, which could be a concern for large map sizes.
The main drawback to depth map shadows is that they don't take materials' transparency into account.

Depth Map Attributes

Shadow Color Applicable to both types of shadows in Maya. Changing the Shadow Color attribute changes the shadow's color seen in the render. It's often a good idea to bring shadow colors a little brighter than pure black, to add to the simulation of diffuse light reflection. You can also map an image file or a texture to the Shadow Color, just as you would map an image to a material.
Dmap Resolution Specifies the resolution (accuracy) of a depth map shadow. The maps are square, so if you set this attribute to 1024, the shadow map is produced as a 1024x1024 pixel image. When setting Dmap Resolutions, try to use values that are powers of 4, such as 128, 256, 512, and 1024. These numbers are easier for Maya to calculate with and can result in faster render times. At very large sizes (4096+), RAM consumption can become a problem. Increasing the resolution also reduces the jagged effect, but creates a sharper shadow edge.
Dmap Filter Size Directly affects the edges of a depth map shadow by making them softer. This attribute, combined with the Dmap Resolution, can smoothly and gradually soften a shadow's edge. Be aware that increasing this value increases render times. Use values between 1 and 3, unless you truly need to go higher.
Dmap Bias When depth map shadow–casting lights are casting long shadows, they can sometimes separate from the objects. This setting allows you to adjust the placement of the shadows, and you usually need to adjust it only for very low light angles (such as a setting sun).

Raytraced Shadows

Raytraced shadows are generally slower to compute, but offer the advantage of lower RAM requirements, soft shadows, and properly cast shadows for objects that have transparency, such as windows. To make raytraced shadows appear in your renderings, you must go to the Render Global Settings window and enable raytracing. Like the Area light, the Spot, Directional, Ambient, and Point lights can cast area shadows. In this case, the soft shadows are created by having the light cast from a circular source. Non–Point light sources create soft shadows (known as penumbral shadows) because a variable amount of the non–Point light source is blocked as an object passes in front of the light.
Transparent objects can affect shadows if the shadows are raytraced. However, the color values do not affect shadow color. To cast colored raytraced shadows, you must set or map the transparency color for the material.

Raytraced Shadow Attributes

Light Radius  Sets the imaginary size of the circular Area light effect.
Shadow Rays Controls the sampling of soft shadows. If you use a low number, the shadows look speckled, but render faster. This is similar to the way that Dmap Filter Size works with depth map shadows, in that increasing the Shadow Rays setting reduces the shadow's graininess.
Ray Depth Limit This setting enables you to limit the number of times a light bounces from reflective and refractive materials. You can raise this value if you want to allow raytraced light rays to bounce around the scene before eventually creating a shadow.

Area Light Shadows

If you set Area lights to cast raytraced shadows, the shadows are calculated from the rectangular Area light icon, based on its size. The results are similar to circular Area lights. As with circular Area lights, more Shadow Rays soften the shadow, but result in substantially longer render times.

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