During my specialisation project, I had to thoroughly research correct topology for character models, as Elauriel was destined to undergo a lot of animation later on! As a 3D artist, it is sometimes very easy to forget about or glaze over proper topological practices. We are usually thinking about how to make the model look wonderful… and wonder why we have an angry technical artist and animator after us! Poor topology means difficult rigging, skinning, and animation. It is our job as 3D Artists to ensure that the topology of the mesh is suitable for the processes that come after our own job.
If you have read my previous blog posts on this project, you will know that I finished the sculpt of my character, Elauriel. If you haven’t, have a look at her below!
Elauriel is to be the protagonist of a short film, so she will be animated – a lot! This means I had to really understand what topology would deform well, and what wouldn’t.
I chose Topogun to perform the retopology process. I love Topogun, as its sole purpose is retopology, which means it has more tools which greatly aid in the process. I find retopology even better than modelling, as you can focus completely on the actual topology, rather than having to worry about the form as well.
So without further ado, let’s talk about character topology!
General Topology Tips
There are some general guidelines which greatly assist in creating good topology. There are no strict rules, and the guidelines are dependent on the project you are creating.
It is a good practice to try and use mainly quads when modelling characters. Quads deform and shade well. Try and refrain from using triangles in most cases – they cut off edge flow, can create deformation issues in some areas, and don’t shade well. It’s also a good idea to completely avoid Ngons, as they also create render and smoothing issues, along with bad deformation. While triangles can be used in certain situations, it is best to re-route the topology to allow for a quad based mesh. Ngons should never be used in organic models, so steer completely clear of them!
The topology of the face is extremely important, especially in a character who will be making lots of different expressions!
It is important to remember that there are lots of ways to do facial topology, and not just one right way. I will just be talking about the topological flow I used.
There are several loops in the face which must exist for the face to deform properly. The important thing with facial topology is to keep clean edge loops that flow along the muscles of the face, so when they deform the move in the correct way.
I have put an example above to demonstrate how topology works in this area. I researched quite a lot of ways to do the topology here, but I thought that this image definitely demonstrated it the most efficiently. You can see my character model’s topology highlighted in a similar way!
For reference, we will refer to the red part of the mesh as the lip loops, the blue part as the “smile muscle” (for ease, as facial anatomy is very complicated), the green part as the eye loops, the orange as the eyebrow-cheekbone loop and the yellow as the nose definition. It seems like a lot to remember, but stay with me!
The best place to start with retopology is the eyes, as most of the facial structure is dependant on this area. The eyes loops should have geometry that flows in perfect circular loops, going around the eyelids and outer eye area. They need a lot of density because they will stretch when they close – so don’t skimp on the loops here! The eyes are actually pretty easy to create good topology on, so long as you follow the loops and create enough denstiy for the eyelid.
The lip loops follow a very similar flow, containing several loops which run around the lips and around the chin and nose area. This area once again requires a higher polygon density, as it will need to deform in all different sort of ways.
The smile muscle connects up through the cheeks and flows into the nose area. The topology is structured in this way to support better animation. All of the areas highlighted here work together in the deformtaion process. For example, when a character smiles of frowns, the cheeks will need to move along with the mouth. When the smile muscle exists, it ensures that these expressions can be natural and realistic.
The eyebrow-cheekbone loop performs a similar function to the smile muscle. It connects the eyebrow and the cheek so that when they deform, they interact with eachother.
The nose definition area is a topological surface which defines the shapes of the nose and nostrils. It’s a good idea to try and contain the loops and edges used here. Refrain from trying to get them to flow into the cheek, as that can create strange deformation. Connecting them to the lip loops is a good method to use.
A few more tips for the face – nothing is worse than topology that doesn’t have the right edge flow. Edges that abruptly end or flow in the wrong direction (meaning they don’t follow the muscle structure in the face), creates awkward deformation. Another tip is to avoid triangles in the face, especially near the mouth or eyes. Triangles cut off edge flow and generally don’t deform well in this area.
These simple rules will help create quality topology for any character. This research helped me create some of the best topology I have seen in any of my character models.
Joints are extremely important to pay attention to. I have done some poor topology in this area in past models, and it severely impacts deformation. These areas really have to be done perfectly – there isn’t much room for error! Luckily, there is a fairly simple way to create the topology for this area.
If you take a look at the image below, it shows the difference between two types of topology for joints – the top one is clearly working, but the bottom is deforming poorly.
You might think that three loops would be better on a joint, because the more density the better, right? This isn’t the case with the joint area. On the elbow or knee joint, there should be two whole loops which flow around the entire joint.
There should be a set of edges in the middle of the joint (on the back where the elbow is, or the front of the knee) exactly where it will bend. These edges are not a loop, as their flow is cut off to prevent the middle loop flowing around the whole joint. This might sound confusing, but have a look at the example below on my character model. It is very easy to do.
The same principle is used for the knee, it is just reversed, as you can see below.
This method ensures that the topology will be clean, and the joint will be able to deform properly. It’s also good idea to add more supporting edge loops around the join area to assist in deformation. You can see that I have done this in my model.
Topology is a vital thing to understand as a 3D artist – but it can be very confusing and difficult to learn. It has taken me a long time to understand topology and improve my skills in this area – and I am still learning better practices. Research is definitely the best way to understand topology – so don’t wing it! I have before, and it really shows. Finding proper reference will improve a character model immensely, and I feel I can definitely see the progress in this model compared to past ones.
Thankyou for reading, and I hope this inspires you to learn more about topology!
Face Topology. (2016). Polycount. Retrieved 23 August 2016, from http://wiki.polycount.com/wiki/FaceTopology
Face Topology [Breakdown Guide]. (2016). Polycount. Retrieved 23 August 2016, from http://polycount.com/discussion/80005
Limb Topology. (2016). Polycount. Retrieved 23 August 2016, from http://wiki.polycount.com/wiki/Limb_Topology
Masters, M. (2014). Why Are Ngons and Triangles so Bad?. Digital-Tutors Blog. Retrieved 23 August 2016, from http://blog.digitaltutors.com/ngons-triangles-bad/