There are many different types of modeling technologies available to the 3D artist today. There are six common types of model data that can be used to generate a 3D model on a computer, and each of these offer distinct advantages and disadvantages to the 3D artist, regardless of their chosen discipline. This short series of articles will examine each of these types individually. Polygons
Polygon surfaces (also referred to as “meshes” or “mesh modeling”) are created by connecting a series of floating points, or vertices, together via edges to define triangular faces with which to create a 3D model. Mesh modeling is available in almost all non-CAD and some CAD software.
Most modern polygon modelers focus on “quad modeling”, where the base unit of the model is a four cornered polygon. This allows for workflow enhancements and better conversion to subdivision surfaces. The typical process for this workflow is to create a base mesh (a cube or plane), and add detail via extrusions and edge loops, and change the form via direct editing of individual points/edges/faces.
One of the largest drawbacks to polygon models is that once they begin to get more complex, such as when adding edges to help smooth out a curved surface, they rapidly get more difficult to manipulate. Once this detail is added, it is “stuck” – there is no automatic ability to increase or decrease detail. In some cases, models with too little detail can lead to a course looking model, where the object is blocky and triangular due to lack of geometric detail.
If you are a product designer or engineer and work in CAD, you probably have encountered polygon meshes when viewing .STL files, or opening 3D scan data – which is usually converted from point clouds into polygonal meshes. You have seen them in video games and the SolidWorks model viewer window (interesting fact; the STL generated by SolidWorks is the same mesh that it shows in the 3D editor). Try programs like Blender, Maya, modo, or Rhino, to check out some polygon modeling techniques. Even though Rhino is mostly a NURBs-based program, it does carry some polygon editing tools. If you want to see what it’s like to have a pure polygon modeling experience (with no quads, edge loops, etc), check out Milkshape 3D. Sketchup is also a polygonal-based modeling app, however it uses a non-standard interface. For a completely different way of working with polygons, try the free sculpting software, Sculptris. It uses dynamic polygon remeshing to let you create models like clay in your hands. Below is a sped up video showing what it’s like to mesh model in 3DS Max (you may want to turn down or mute the volume).
- Easy to manipulate low resolution models
- Quick to rough out a concept
- Great for starting out when learning 3D modeling
- Any model can be turned into a mesh model, and all files for 3D printing use mesh models.
- Difficult to manipulate more complex models
- Models cannot be considered “arbitrarily smooth”.
- Does not require models to be watertight or even physically producible.