3D modeling software is essentially based on the manipulation of basic shapes. These basic shapes can be cubes, spheres or cones, or Bezier curves or NURBS. Users can add or delete at will.
The software usually provides a set of tools that can be used to shape basic shapes into more complex shapes, such as cars or characters. These modeling tools can be simple geometric transformations, or "solid construction geometry", or perform more complex transformations, so that various parts of the shape can be modified, cut or twisted. 3D modeling software can handle other attributes, such as the texture of the object, its color, how it converts light, etc.
3D modeling software can save the obtained scene in a file in a given format so that other programs can use it to create animations or games. The software is also able to manage the position and direction of the camera and the presence of different light sources, so you can view precise points in the scene and illuminate certain parts of the scene.
3D modeling software usually has modules for rendering 3D scenes. The purpose of the latter is to create a "realistic" image or animation from the modeled scene.
In the case of very complex rendering requiring high calculation time, these two softwares are completely different, such as Blender and Yafray.
In some commonly used modeling software, modeling can be divided into the following types:
1 Polygonal modeling
Assimilate the model into a set of polygons: therefore, this polyhedron is described by a list of vertices and edges. If the polygon is oriented, we can distinguish the exterior and interior of the model. If we want to eliminate the ambiguity caused by non-planar polygons, we will only use triangles: the modeler can enforce this triangulation.
If there is no smoothing effect, if the multi-face definition is weak, the object will appear to have corners. Generally, the Gouraud smoothing performed by the 3D graphics card is sufficient to make the model appear smoother.
Polygon modeling uses the same basic tools in all 3D software, as well as some tools specific to general software, special software, and plug-ins and scripts.
Among these tools, the most common are extrusion, cutting (cutting, splitting, etc.), welding/retraction (welding/collapsing) and rotation.
2 Curve modeling (NURBS) is modeled
through NURBS (non-uniform rational basic spline/non-spline basic rational non-example), which is a curve network formed by controlling the vertices. The curve interpolation between these points can be done automatically according to the NURBS algorithm, it can be done automatically by manipulating the tangent of the Bézier curve, or even by modifying the interpolation parameters.
3 Modeling by surface subdivision
This method combines some of the two classic methods (polygon and NURBS). Due to the automatic subdivision of part of the surface, the processing speed can be increased. In this way, you can add details only in certain locations without worrying about the number of faces contained in the entire object.
It is similar to polygon modeling through the technology used in the shape creation process, and similar to NURBS modeling in surface rendering (ie its rounding).