The concept of 3D modeling is extensively used nowadays in movies, videogames, architecture, publishing, geology, medical science etc. 3D modeling in simple words can be described as creation of a 3D image of an object using specialized software, and the process involves development of a mathematical representation of an object in three dimensions. If you want to become a 3D artist, its paramount for you to become familiar with the term polygon mesh, which is a collection of vertices, edges and faces. A wide range of 3D graphics software packages is available in tech market to create polygon meshes for constructing 3D models.
Primitive Modeling: Primitive modeling involves use of geometric shapes like cylinders, cones, cubes and spheres for the purpose of creating 3D models. This technique is best used in architecture for creating 3D images of furniture, building etc. Artists should not try using it for organic models or human 3D models. Max, Maya and 3DS are some software you can use for primitive modeling as they offer you tools changing shapes of an image.
Polygonal Modeling: This technique involves use of triangles, cubes, hexagons and other shapes. Polygonal modeling is an advanced approach towards creation of 3D models for movies and videogames. Its a very good technique to give an image a realistic appearance, however its important to determine the numbers of polygons one needs to use for a specific 3D image. The higher the number of polygons used, the smoother and realistic the 3D model is.
However, it makes more sense to use millions of polygons for movies rather than games since they have to be more efficient. This is the reason gamers use various techniques to reduce the number of polygons in 3D models so that they can run more smoothly and download quickly. A disadvantage of using polygon modeling is improper representation of curves and complexities in creating surface topology.
Game engines convert polygons with more than three points into triangles since anything more than three points have chances to be non-planar. A good example to explain this is a square which has four points and two triangles. However, a lot of calculation needs to be done to figure out whether or not all the points are co-planar. Therefore, a pre-calculation is required for all polygons greater than three points to ensure all the points are co-planar. And this could be done only by converting those polygons into triangles.
Polygonal Modeling opens avenues for transforming a primitive 3D mesh, such as a cube, hexagon or cylinder, into a 3D model. You can use a fewer polygons in an image to create a mesh of polygons and later add refinement to it. Polygonal modeling, without a doubt, is the most-used technique among 3D game developers.
NURBS Modeling: Unlike Polygonal Modeling, NURBS(Non-uniform rational B-spline) Modeling allows artists to create smooth curves and surfaces in 3D models. However, a 3D game artist has to be very smart when using NURBS Modeling as a 3D image cant be altered once it is created.
An artist can create a NURBS surface by using two or more curves in 3D space. Control vertices allow manipulation along the X,Y, or Z axis. This technique is not very popular for games and films and is commonly used for engineering and CAD. NURBS is known for versatility, precise design and speedy creating of 3D models. With NURBS, it becomes easier to edit, enable accurate data transfer and integration with many programs to create high quality designs and models. Control Points, Knot Vector and Functionsare important terms to know for 3D game developers to use NURBS.
Sub-division Modelling: The mix of Polygonal Modeling and NURBS is called as Sub-division Modeling. This hybrid technique involves creation of a 3D model via polygon model and then converting it into the sub-division model. This technique helps artists control the refinement of the 3D model in particular areas and easily transfer models between different software. A developer needs to subdivide and refine until polygonal detail is good enough to display the intended 3D model. The more you subdivide a surface, the smoother it becomes.
Surface Modeling: This technique helps create a 3D spline by using a 2D spline and is different from NURBS. It is widely used to create organic 3D models in movies and offers flexibility. A developer can easily make a 3D representation with different requirements by making use of geometric entities like surfaces and curves.
Advantages of surface modeling involve less ambiguity, easy identification of complex surfaces, removal of hidden lines and addition of realism. However, this technique requires a lot of hard work, time and high storage space.