Every week more people are getting into digital 3D art. There are a variety of reasons for this from a wide range of new users. Some have a story to tell in a single image while others want to create the next Pixar masterpiece… or as close as they can get. Others want to supplement their incomes and who can blame them in the second year of the pandemic where income sources have all but dried up.
No matter the reason or the usage they all run into this strange new term… polygon count or poly count and its cousins high and low poly. To those of us that have been in this creative outlet for a while, it’s a simple fact that in some cases helped shaped our futures as artists and drove us to acquire certain types of software. For the rookie, however, it can be a strange and confusing terminology.
If you are new to this and happen to look up what a “polygon” is… heaven help you. This is what you get from Wikipedia:
“In geometry, a polygon (/ˈpɒlɪɡɒn/) is a plane figure that is described by a finite number of straight-line segments connected to form a closed polygonal chain or polygonal circuit. The solid plane region, the bounding circuit, or the two together, maybe called a polygon…
…a simple polygon is one that does not intersect itself. Mathematicians are often concerned only with the bounding polygonal chains of simple polygons and they often define a polygon accordingly."
Say what??? No seriously… if this is what you see when you first delve into 3D how can you not be confused?
Forget what you read from Wikipedia and let’s look at this in 3D mesh terms.
Two cylinders of which the far-right cylinder has the most polys (1836 out of 2052).
If you don’t know what a mesh is… it’s not complicated. A mesh is what a 3D character, figure, or prop is made of. If you have a human female character… the body, clothing, accessories are all made of mesh… therefore… they are all meshes. It is a widely generic term.
Now we get to the poly count part. Mesh is made up of polygons. In an oversimplification, these polygons can be quads or triangles in shape. A mesh that is 5K has 5000 polygons. Triangles are efficient but sometimes not pretty. Quads are pretty but can lead to a higher polycount. The more triangles and quads you have the smoother the mesh. Again, this is a simplification, but the general idea is sound.
If you are animating a prop or character you might quads if available as they can handle a lot of situations without poke through underlying layers of the mesh such as clothing on a character. Topology, another term, is the surface area of the mesh. Quads make for clean topology which makes for clean movement, but triangles are prevalent due to their ability to reduce poly count.
Now we get to face count. What??? You’ll hear this term, might as well deal with it. Let’s keep this simple too… just think of face count as poly count even though they might not be technically the same. For our purposes, this will work until you have more 3D experience.
We’ve been through all this to get to here.
If you are more interested in high-quality, single image renders then you will be working in the High Poly world. Daz, Poser, and others fit this realm though they can do low poly.
If you are considering gaming, machinima, or real-time animation then you are in a low poly world. Applications like iClone are lower poly, geared to work in real-time so you can see immediately what you are working on instead of waiting for a render.
You can use a low poly character or prop in Daz or Poser and conversely you can use high poly versions in apps like iClone, but it will degrade performance and limit the number of objects you can have on-screen.
Comparison of Low Poly (left) and High Poly (right). Both applications can use either model. iClone model is mainly quads, DAZ model mainly triangles.
Real-time playback can be affected when the engine behind it all is overloaded with too many polys. Doesn’t matter if it is a game or an animated sequence, it will drag or possibly become choppy in playback.
We also use the term weight to describe high and low poly as a high poly object is heavy and a low poly object is light. This reflects the load on the engine concerning the number of polys in the model. One mesh might be 50K polygons while another mesh might be 1.5 million polys or more. You can see where the latter is a “heavy” mesh that has a lot of polys which, in turn, puts a strain on the 3D engine driving it all.
While this is getting a bit wordy there is one more term you need to know and that is decimation. When you take a heavy poly object and use an application to reduce the number of polys this is called decimation. In essence, you can decimate a 1.5 million poly object to a 15K poly object, but it might not look so good and certainly won’t look like the high poly original without a lot of technical skill.
Decimation also takes nice, even topology quads and mutilates them into triangles to save weight and reduce the “overhead” on the 3D engine (how many resources it eats up). Decimation has its pros and cons but also has its place in our toolbox when properly used.
Hopefully, by now you know what it means if I say I have a light character mesh or a high poly prop. If you are using an app like iClone and it’s dragging along then you have more polys in the scene than the engine wants to work with. If, on the other hand, you want to make stunning character portraits, or gorgeous landscape single image renders then the higher poly models will make it look much better.
DAZ, Poser, and iClone handle a wide variety of poly counts depending on the situation. It matters more if you are animating or single image rendering of which all three are capable applications.
M.D. McCallum, aka WarLord, is an international award-winning commercial graphics artist, 3D animator, published author, project director, and webmaster with a freelance career that spans over 20 years. Now retired, M.D. is currently working part-time on writing and select character development projects. You can learn more about MD on his website.