The Three Methods of Modeling

There are three types of modeling that are used to create a 3D model, these are; spline modeling, box modeling and poly modeling.

The first type of 3D modeling discovered is spline modeling. Spline modeling has also been referred to as patch modeling and allows a curve to be created with the use of two control points. These points are created in multiples to create the skeletal system of the model. This form of modeling is best for objects that are not going to be animated, as they require a lot of modifications to be suitable for the animation process. Cars, furniture and real estate models are examples of which types of models work best within the Spline modeling process. These types of models require an extensive amount of curved shapes and therefore work best with Spline modeling.

The modeling form that lies the most similar to sculpting is the technique called box modeling. It begins with a cube shaped, and details the object by removing layers or slices. Again, box models can be difficult to animate and take extended periods of time to create, and perfect. Box modeling is used for objects with hard lines such as tall, traditional buildings.

Poly modeling is also referred to as edge extrusion. It is one of the most precise techniques as it will begin with a 3D image consisting of points, which are built upon. These sets of four points are referred to as quads, and the second is attached to the first, and the third is attached to the second, and so on. The model is created from the bottom up, and can take extended periods of time but requires less adjusting than traditional modeling methods. Shell models, which contain the surface shape without an interior, can be easily created with poly modeling. The most advanced technique; poly modeling has been popularized with new technology and software.

Creating 3D models with NURB Modeling

NURB modeling or, non uniform rational b-spline modeling creates 3d models with varying surface representations. This type of modeling allows for the curves that we see in sleek vehicle models and architecturally curved buildings.

Specific aspects of a NURB model include; knot vector, control points and the order of these items. Control points are arranged in a specific order, thereby creating the curve that is represented in the 3D model. Weight is applied to certain points on the curve and these weighted points account for the direction of the curve.

NURB models have grown popular in the creation of organic 3d models as the surfaces represented are actual curves, not tiny lines creating curved appearances like other 3D model creation software.

The use of NURBs within 3D modeling allows the user to create shape within its compact form. They allow mapping within the 3D space of the surface predetermined by control points. These control points determining the shape of the space, thereby resulting in a feasible 3D model.

The creation of NURBs has allowed higher level tools to be created. These tools include; positional continuity tools, tangential continuity tools as well as curvature continuity tools.

Some 3D model creation software has been created to use solely NURBs modeling processes. Maya is an example of this software. Maya has been adapted to use NURBs modeling and therefore is adequate for 3D modeling projects that require curved, detailed surfaces required in organic modeling.

There are many benefits to using NURBs curves in the creation of 3D models; they reduce the memory consumption when storing shapes, and using the curbs can create a wide variety of shapes in varying sizes. NURBs curves have the ability to be used in a 2 or 3D modeling space and therefore are a versatile design tool. The curves can be assessed using specific algorithms quickly and efficiently.

Types of 3D Modeling: Polygonal Modeling

Polygon modeling refers to 3D modeling which use polygons to create the shell of a 3D model. The polygons are used to create the mesh surface with the uses of vertexes in a linear pattern.
There are three common shapes created with the use of polygonal 3D modeling; triangles, quads, and elements. Triangles are formed when three sided polygons are uses, quads are formed with four sided polygons are used, and an element is created by a group of polygons connected together at a shared point.

Mesh 3D modeling uses vertexes as coordination points on the surface where three of the five surfaces of the polygon are attached to one another. Two of these vertexes that become an edge are connected by a straight line and then, each one of the polygons that are used to create the 3D modeling figure.

Polygons are the most adept form of 3D modeling for a computer to create. They can be textured or create the appearance of curved surfaces with the use of many tiny lines.

Primitives are the shapes formed within the program within the modeling environment that can be used to create a mesh. 3D modeling primitives consist of spheres, cylinders, cubes, squares, triangles and discs. Spheres are created with the use of multiple triangles to create the curved surface required for the round representation.

There are six basic operations formed in polygonal modeling. Creations refer to a new geometrical shape being formed from another mathematical object. Lofting refers to the action of generating a mesh by continuing a shape over a pattern. Extruding also copies a shape, but over the period of a line rather than a space. Revolving refers to using a shape to rotating and copying the shape around a specific point and lastly, marching cubes which can create shapes using specific algorithms.