Smooth Surfaces: Using Subdivision Surfaces

Subdivision surfaces are used in order to build and create images and models. Maya has 2 options for modeling: NURBS and subdivision surfaces. With surfaces, an initial geometric shape is divided and then the surfaces can be altered by changing the dimensions and lengths of the subdivisions. This is a very easy way to create intricate objects and can be combined with polygonal modeling, as well as NURBS. One surface can be altered to create very complex shapes. The more control points added to the subdivisions, the more detail and complexity that can be added.

Advantages

This type of modeling works by having the surface divided into more and more subdivisions, which allows for more and more detail. The base mesh is divided and then subdivided. The more subdivision, the more control that can be applied to that surface. This allows for more control over the shape than polygonal modeling and can create sharp edges. Because the surfaces are all continuous, there are no seam issues, something that is a problem with NURBS. All the subdivision surfaces can be binded to the skeleton, and when the finer level is used, this makes everything very smooth. The 2 main issues with this modeling choice are that it is very difficult to duplicate and attach, and it cannot be rendered using mental rays.

Implementations

There are hierarchical subdivision surfaces and subdiv proxy. It is possible to take a polygon object and convert this into a subdivision surface by using the proxy. This model can then be smoothed until a high quality image is produced. Subdivision levels are added for each polygonal face. Before further smoothing the original proxy model, it is recommended that a copy of this image is made before altering the proxy copy.

In some cases, it is possible to see both the subdivision copy and the original polygonal object. The normal hierarchical subdivisions is the main way that subdivision surfaces work. Larger areas are less important on the hierarchy, and the smaller subdivision will have higher ranking. The smaller areas correspond to finer details.

Rendering

It is possible to use this type of subdivision at the end of the 3D animation production. Rendering applications can produce the best surfaces from low resolution meshes. The amount of storage space that is needed is much less, as it is not necessary to smooth between 2 levels. What is needed is to smooth between the main the finer levels. This can render much faster, but still produces smooth objects. There can be some issues with topography using these, but there are ways to work around them if necessary. Many times, if the same figure is used, a script can be written to constantly produce this type of figure.

Painting

These different subdivision surfaces can be used for painting. Instead of painting on the model surface, choose to paint areas based on the subdivision cage. If the detail is fine enough, then this is an easy way to paint the object. Use the eyedropper tool to fill the area inside each subdivision. It is possible to set different textures as well as a variety of colors.