There are several methods of 3D modeling that a 3D modeler uses: polygonal, spline and NURBS modeling. They can be used both separately and in combination.
Polygonal modeling
Polygonal modeling is a type of 3D modeling, which appeared at the time when to locate a point you had to manually enter its X, Y, Z coordinates. If you set three coordinate points as vertices and connect them with edges, you get a triangle, which in 3D modeling is called a polygon.
A polygon with three vertices is called a triangulated polygon, a polygon with four vertices is called a quadriangulated polygon. If you look at the models created with polygons, you will notice that most of them are created by polygons with four and three vertices. Each polygon can have its own texture and color, and by combining several polygons you can get a model of any object. Interconnected polygons form a polygonal mesh or a polygonal object.
In order to keep the edges of the model from having a faceted appearance, it is necessary for the polygons to be small and the surface of the object to consist of small planes.
If it is supposed to model an object accurately (high-polygonal modeling), or to enlarge its image in the future, it is necessary to build a model with a large number of polygons, although, if the object model is viewed from afar without approximation, a small number of polygons will be sufficient. Such models will be called high-polygonal and low-polygonal, respectively.
Despite the fact that polygonal modeling is used quite often, especially in the creation of three-dimensional real-time computer games, recently there has been a shift from polygon modeling to work with splines (spline modeling).
Spline modeling
Spline model ing is a type of 3D modeling, in which the model is created using splines( spline – from English spline – a flexible mold, in 3D – a three-dimensional curve). The spline lines are defined by a three-dimensional set of control points in space, which determine the smoothness of the curve. All splines are reduced to a spline framework, on the basis of which the enveloping three-dimensional geometric surface will be created.
In addition, spline modeling uses spline primitives (parametric objects used to model an object). Basic spline primitives are:
- Line (Line);
- Arc (Arc);
- Helix (Helix).
- Circle Circle (Circle);
- Ring (Donut);
- Ellipse;
- Rectangle;
- Polygon (NGon);
- A polygon in the shape of a star (Star);
- Section (Section);
- Spline Text (Text).
There are other more complex spline objects in various programs that allow you to work with splines. The advantage of spline objects is that they have flexible settings and you can always go back to change their shape.
Spline or polygonal modeling?
Spline modeling is more accurate, and the quality of the object does not change as you scale (zoom in). In spline modeling, the shape of the jug is described by a set of curves along the equator of the ball. The surface built with splines can be scaled and manufactured with the accuracy that is needed and can be set at the prototyping stage.
The jug shapes created with polygons have varying degrees of detail between planes. A product with 260 polygons has a degree of detail of 35 degrees, a product with 520 polygons has 25 degrees, and a product with 1280 polygons has 10 degrees between faces. Despite the fact that from afar the product seems smooth, and the number of polygons is more than 1000, when making such an object there will be small roughnesses, because even on a small object the angle of 10 degrees between the planes is noticeable.
Polygonal and spline modeling can be compared using raster and vector images: a vector image can be scaled to any extent and its quality will not be lost, while when a raster image is enlarged, line quality will be lost. More clearly on the picture:
3D models created using spline or polygonal modeling are usually saved in two formats: IGES and STL formats, respectively. Most often STL formats are used at prototyping installations, but with the help of special programs IGES format can be converted to STL. Note that the reverse conversion is not possible.
A special case of spline modeling, which has already become a separate type of 3D modeling, is NURBS modeling.
NURBS modeling
NURBS modeling or Non-Uniform Rational B-Spline technology is a technology of non-uniform rational B-splines, creating smooth shapes and models that do not have sharp edges like polygonal models. It is because of this distinctive feature that NURBS technology is used to build organic models and objects (plants, animals, people).
The NURBS curves used in this simulation are of two types: Point curves and CV (Control Vertex ) curves. Point curves are controlled by vertices directly on the line or object itself, while Control Vertex curves are controlled by points lying outside the line or object. The difference can be clearly seen in the illustration:
Programs for 3D modeling
- Autodesk 3d max (with the help of this program some scenes of such films as “The Matrix”, “Jurassic Park”, “Lara Croft” and others were created);
- Autodesk Maya (a very popular program in cinematography. It was used to create the characters Gollum (“Lord of the Rings”), Little Stewart the mouse and even Shrek);
- Autodesk Softimage (this program was used to create commercials for M&M’s and Coca-Cola, movies “Sin City”, “Avatar”, “Brothers Grimm”);
- Autodesk Mudbox is a program that specializes in high-polygonal modeling;
- ZBrush by Pixologic is a program specifically designed for high-polygon modeling and 3D sculpting;
- Houdini by Side Effects Software;
- Lightwave 3D from NewTek;
- Modo by Luxology;
- Rhinoceros 3D is a program specialized in NURBS modeling;
- Cinema 4d by Maxon;
- others.
KOLORO team of 3D designers and modelers has extensive experience in creating 3D models, we use different types of modeling and different programs for modeling objects. We have an individual approach to each customer, and in the process of working with him, we provide the necessary support, consult on controversial and related issues. We guarantee the high quality of our work and strict compliance with the terms and requirements of the client.
Contact us by phone or fill out our contact form so that we can offer you the best way to complete your project. Send us your 3D model for an estimate. Consultation and cost estimation – free of charge!
Our contacts: +38(057)-760-26-05; +38(057)-760-26-06; +38(099)-618-87-50; info@koloro.ua.
