If you’ve done any high resolution sculpting, or imported some very dense 3D scans, you’ll definitely want to do something with all those vertices. Here are a few tips and tools to help you massively reduce the amount of verts in your absolute unit.
Have a Plan
Every single retopology job is going to be different, so it’s good to get an idea for what you’re going to do and how you’re going to approach it before you go diving in. As a general rule of thumb, go for cylindrical parts first (legs, arms, and torsos are relatively easy), and then try connecting them afterward (hips, shoulders, and heads can be more challenging).
There are several tools available for Blender users to help speed up your retopology job and/or make your life easier. Perhaps the most notable being Retopoflow. Others include Tesselator, LoopTools (addon included with Blender), Grease Pencil, and BSurfaces (included in 2.79).
1. Think Big
Start by thinking in LARGE, general shapes. Don’t get into the fine details too early. You can always add that extra detail later on with loopcuts and subdivisions to give you any extra geometry that you may be missing.
2. Even Detail
Keep mesh density as even as you can. This is especially difficult in the beginning. You may be tempted to dive into the finer intricacies of a dinosaur’s toenail or something like that, but don’t! This will give you tons of geometry in one part of your model, and not enough in other parts.
3. Work Smarter, Not Harder
A lot of these tips are related, but it’s good to keep them all in perspective. If your sculpt or scan is symmetrical, do yourself a favor and use the mirror modifier. Not only does this cut your work in half (no, literally), but it also keeps the number of verticies even on both sides so you don’t have to remember how many loopcuts you put around your model’s left elbow. They’re already in place.
4. Think In Loops
If you just go placing quads all over your model with no plan, you’re going to end up with some problems. Yes, there are tools and addons that make adding squares a walk in the park, but that’s not the way you should approach an entire model. Start by targeting cylindrical shapes first. Think: arms, legs, fingers, toes, torsos, thighs, elephant trunks, tentacles, etc. Once you have those in place, focus on joining those shapes later. Connect the arm to the torso (shoulder), leg to the torso (hips and groin), etc.
5. Keep At It
Practice. Seriously! I’m terrible at retopologizing, but that’s why I spent the time creating this video series. I made these mistakes so you don’t have to. Hopefully this helps you out! So if you only get one takeaway from this entire series, just keep practicing retopologizing models. There are tons of models online that have less than stellar topology for animation, so why not give retopology a shot!