Modeling Test

Quad

A quad is a polygon made up of four sides or edges that are connected by four vertices, making a four sided face. Quads are the polygon type that you'll want to strive for when creating 3D models. Quads will ensure your mesh has clean topology, and that your model will deform properly when animated.

Edge Loop

An Edge Loop is a series of edges connected across a surface, with the last edge meeting up with the first edge, creating a ring or loop. Edge loops are especially important for maintaining hard edges in a mesh, and also for more organic models. For example, in order for an arm to deform properly there will need to be edge loops on each side of the elbow joint so there is enough resolution.

Beveling

Beveling is the process of chamfering, or creating rounded edges on a mesh. Beveling expands each vertex and edge into a new face. In the real world objects rarely have completely hard edges. So beveling is required to lose some of the computer generated look that comes with 3D modeling.

NURBS surfaces

NURBS stands for non-uniform rational b-spline (NURBS). NURBS are commonly used for very smooth objects because they don't require as many points to create the same look as polygon geometry would. A NURBS surface always has four sides that are defined by control points.

Normals

Surface normals are used by your 3D application to determine the direction that light will bounce off of geometry. This is very helpful to get control over how the light reacts to certain materials on your 3D objects.

Weight Painting

Weight painting is a vital step once the skeleton has been created. Even though the bones are put into place, it doesn't mean the 3D model will be able to deform exactly how you want. When a mesh is bound to the skeleton, the computer doesn't know how much influence each joint should have over each vertex, so it averages the weight out based on the distance from the joint to the mesh. Basically painting weights allows you to manually set how much influence a joint has on a particular area of the model and correct the deformations on the 3D mesh. For example, if the leg joint has too much influence on the model it might affect the torso area giving you unrealistic results.

Topology

Whatever type of geometry you use it will either be created by NURBS, or points, edges, and faces. The way these components are connected together and the flow around the 3D object is the topology. You can think of topology as the type of polygon faces, the type of vertices and the flow of the edges.

UV Mapping

3D object has many sides and a computer doesn't know how to correctly put a 2D texture onto a 3D object. A UV map is basically the 3D model stretched out into a flat 2D image. Each face on your polygon object is tied to a face on the UV map. Now placing a 2D texture onto this new 2D representation of your 3D object is much easier.

Blend Shapes

A blend shape, or morph depending on your 3D application, allows you to change the shape of one object into the shape of another object. When rigging, a common use for blend shapes is to set up poses for facial animation. This might be lip sync poses or more complex expressions like a smile or frown. You can tie all these new poses into the original face mesh and have it operate all on one control slider. For example, if you want to raise an eyebrow you can model a face pose with one eyebrow raised, connect it to a blend shape and using the slider with a value of 0 to 100 to either raise or lower the eyebrow. This is a great way for the animator to be able to quickly make face poses without having to move individual facial controls around. There are some downsides to using blend shapes for facial poses, because the edit ability can be limited. Riggers often will give the animators both blend shape options and traditional control points to use them in conjunction.

Bump Maps

A bump map gives the illusion of depth or relief on a texture without greatly increasing render time. For example, the raised surface on a penny can be faked by using a bump map. The computer determines where areas on the image need to be raised by reading the black, white and grey scale data on the graphic.

Faces

A face is the most basic part of a 3D polygon. When three or more edges are connected together, the face is what fills in the empty space between the edges and makes up what is visible on a polygon mesh. Faces are the areas on your model that gets shading material applied to them.

Normal Maps

A normal map creates the illusion of detail without having to rely on a high poly count. For example, a character can be detailed into a sculpting program like ZBrush, and all the information can be baked onto a normal map and transferred to a low poly character, giving the illusion of detail without increasing the actual poly count for the model. Game studios utilize normal maps often because they need to stay within a tight polygon budget, but still need a high level of detail.

Shaders

A shader describes the entire material on an object, how the light is reflected, how it's absorbed, translucency and bump maps, which you will learn about a little later on in this post. Shaders and textures can often times be confused, but a texture is something that gets connected to a shader to give the 3D object its particular look.

Triangle

A triangle is the simplest polygon that is made up of three sides or edges connected by three vertices, making a three sided face. When modeling, triangles are typically a polygon type often avoided. When creating complex meshes, triangles tend to pose a problem when subdividing geometry to increase resolution, and when a mesh will be deformed or animated.

Vertex

A vertex is the smallest component of a polygon model. It is simply a point in 3D space. By connecting multiple vertices (the plural of a single vertex) together you can create a polygon model. These points can be manipulated to create the desired shape.

Edges

An edge is another component of a polygon. Edges help define the shape of the models, but they can also be used to transform them. An edge is defined by two vertices at their end points. Together, vertices, edges and faces are the components that all help to define the shape of a polygonal object.

N-Gon

An n-gon is a polygon that is made up of 5 or more sides or edges connected by 5 or more vertices. It's important to keep in mind an n-gon is typically related to a five sided polygon, but it's not limited to just 5 sides. An n-gon should always be avoided, they often pose problems at render time, when texturing, and especially when deforming for animation.

Constraint

Constraints are very important in both the rigging and animation process. Typically your 3D application will have several options for constraining. Constraints limit an object's position, rotation and scale based off of the attributes of the parent object. For example, by taking two separate spheres, applying a parent constraint, and then deciding which is the parent and which is the child, you can select just one and the other will follow whatever the parent is doing. Setting up constraints is a vital step when creating control curves for the rig. For example, you will need to determine the type of affect that a control curve has on an individual joint. Setting up constraints will allow you to do this.

Control Curves

Control curves are created by the rigger to assist the animator in manipulating joints within the rig. Typically a rig consists of many components that need to be manipulated to move the character in the desired pose. This can be very difficult to do without control curves because the animator would need to hide the mesh to see the skeleton within the character and try to determine which joint manipulates the elbow, for example. Control curves are typically simple NURBS curves placed outside of the character so the animator can easily select the curve to position the character instead of the actual joint.

Extrude

Extruding is one of the primary ways of creating additional geometry on a mesh. The extrude command allows you to pull out extra geometry from a face ("polygon" in 3ds Max), edge or vertex. For instance, you can use the extrude command on the face of a simple cube to pull out the geometry needed to create fingers. These additional extrusions can be edited and manipulated just like any other area of the mesh.

FK (Forward Kinematics)

Forward Kinematics means your character rig will follow the hierarchal chain. This means more control over your chain, but also means you'd need to position each joint in your chain independently of each other. For example, with FK if you positioned the character's hand the rest of the arm wouldn't follow like it does with IK. Instead you would need to position each joint independently, starting with the upper arm, the elbow and then the wrist. This obviously takes more time than IK, but can give the animator much more control of the poses. Most times riggers will incorporate both FK and IK into the rig to meet the animator's needs.

Baking

In your typical 3D scene you will want to shade, texture and light objects to create the exact look that you want, and then you render. To shorten render times you can bake all the materials, textures and illumination information into an image file. For instance, you could bake all the lighting information directly onto an existing texture, render it once, and then delete the actual lights used in the scene. This is great for games because a light would need to be recalculated in every new frame.

IK (Inverse Kinematics)

Inverse Kinematics means that the child node within your rig's hierarchy can influence the movement of its parents. For ex ample, if you use IK for your character's arm you can position your character's hand and the rest of the arm chain will be calculated. This allows the animator to animate independently of the chain's hierarchy. Because of this IK is great when needing to have a character's arm stay planted on something. For example, pushing against a wall or swinging on a bar.

Normal Maps VS. Bump Maps

Normal maps and bump maps are similar in that they both affect the normals of your geometry and create the illusion of detail without having to rely on extra geometry. The big difference between them is that bump maps just encode height information using black and white values, whereas normal maps use RGB values to signify the orientation of the surface normals. The information in the red, green and blue channels in the normal map corresponds with the X, Y and Z orientation of the surface. Normal maps can typically get more detailed information onto the surface.

Skinning

Skinning is the process of taking the joints or bones of the rig and binding them to the actual 3D mesh. When the joints are bound to the 3D mesh it allows you to move the joints and the mesh will follow. Without skinning the mesh to the joints the joints will have no influence on the actual 3D model.

Joints

Sometimes called bones, you can think of joints for rigging in the same way you think of joints in a human body. They basically work in the same way. Joints are the points of articulation you create to control the model. For instance, if you were to rig a character's arm you would want to place a joint for the upper arm, another joint for the elbow and another joint for the wrist, which allows the animator to rotate the arm in a realistic way.

Specularity

Specularity defines how a surface reflects light. It is basically the texture's reflection of the light source and creates a shiny look. Having the right specularity is important in defining what the 3D object's material is made from. For example, a shiny metal material will have a high level of reflectivity, whereas a flat texture like cement will not.

Subdivision surfaces

Subdivision surfaces, which are sometimes referred to as NURMS (non-uniform rational mesh smooth), are closely related to polygonal geometry. Subdivision surfaces use an algorithm to take polygon geometry and smooth it automatically. For example, in the image above you can see the polygon cage (the cube shape) around the smoothed subdivision surface (the spherical shape inside the cube). You can think of a subdivision surface as a mix of polygonal and NURBS geometry.

Pivot point

The pivot point is the point on a 3D object where any rotation, scale, or moves that you do will occur from. This pivot point can be moved to any position on the model. For example, placing the pivot point on the hinges of a door will tell the computer where it should rotate from.

Deformers

There are many different deformers/modifiers depending on your 3D application which can be utilized to enhance your rigs. Deformers are often used among modelers but they are also extremely helpful for riggers as well. Deformers contain algorithms that can move large sections of vertices on a model to produce organic shapes. For example, when rigging a character you can utilize something like a cluster deformer that allows you to manipulate a large section of vertices by using just one single control. Once created, a cluster can be constrained to a control object. This is great for creating facial controls like cheeks or eyebrows. To learn more about deformers check out this in-depth Maya rigging tutorial on deformers.

Texture Mapping

To create a surface that resembles real life you need to turn to texture mapping. This process is similar to adding decorative paper to a white box. In 3D, texture mapping is the process of adding graphics to a polygon object. These graphics can be anything from photographs to original designs. Textures can help age your object, and give them more appeal and realism.

Driven Keys

To speed up the animation process for the animators, a rigging artist can utilize driven keys when rigging a character. Driven keys allow you to use one control or object to drive multiple different objects and attributes. In the example above we can use a driven key to control the fist position for the hand, with just one single control. A driven key contains two parts: the driver and the driven. The driver is the object in control of the animation. The driven is the objects and attributes that are being controlled by the driver. Typically for regular keyframes an attribute has values keyed to time in the time slider. For a driven key, the attribute has values keyed to the value of the driving attributes. The driver can be another object, or in the case of the example image above it is a control slider.

Transparency Maps

Transparency maps are grey scale textures that use black and white values to signify areas of transparency or opacity on an objects material. For example, when modeling a fence, instead of modeling each individual chain link which would take a significant amount of time, you can use a black and white texture to determine what areas should stay opaque and what should be transparent.

Digital Sculpting

When creating 3D models in an application like Maya the process includes manipulating vertices and edges to get the desired look. While this works, it can be hard to get fine detail that is often required, especially in organic models. Digital sculpting works around this issue by allowing you to create your 3D meshes in much the same way as a traditional sculptor would. You can interactively push and pull areas of your model out, and you can create details like wrinkles and scratches without ever having to select an edge or vertex. Often times a modeler will create the low resolution base mesh in a program like Maya, and import that into digital sculpting applications like ZBrush or Mudbox to be able to create those finer details.

Facial Rigging

When creating complex character rigs the facial rig setup is often a whole different monster. A typical joint or bone setup doesn't work well for a facial rig other than having a joint for the jaw bone because facial movement often requires very stretchy and organic motion. Instead of a normal joint setup, facial rigging usually requires deformers and blend shapes which was discussed previously.

Instances

When working with a 3D set you will often need to create duplicates of a single object, whether it's hundreds of trees or fence posts. Doing this however can greatly increase render time, because the computer has to calculate all this new geometry. Instead of creating a duplicate of an object, you can create an instance. Instances are copies of objects that derive all their information from the original object; because of this the computer only has to calculate the geometry for the original object. It's important to keep in mind that you can't edit an instances shape on its own. If you edit the shape of the original object all of the instances update to reflect that change.

Construction History

While you're working on your 3D models you will likely use a wide range of tools to get the desired result. For example, you may need to extrude many different faces or bevel the edges of the model to create a particular shape. Most 3D applications keep track of all these actions in what is called the construction history. This displays a list of every different tool you've used on your 3D model in the order that you used them. If you need to go back and adjust the settings of a tool you used, you can find it in the construction history. Keep in mind that as your construction history starts to stack up it will slow down your computer, so you will need to delete your construction history periodically.

Polygon geometry

the most commonly used geometry type in 3D. While polygons are commonly used for all types of objects, in order to create very smooth surfaces with polygons means that you'd need to add a lot more geometry than you would with either NURBS or subdivision surfaces.