What is the point of Retopology?

Support Modeling
1

As always, I apologize for this dumb question.

I was watching Jonathan Williamson’s Retopology tutorial on Blendercookie and although it is “interesting” I don’t get the point.

Why would you ever want to go from a high res model, to a low res one???

Assuming:

  1. You will not be using/needing it for a game that needs a low poly character
  2. Your hardware is good enough that you won’t care about faster render times, and can do everything in real time.

Also, if something is high res enough, wouldn’t “weight painting” or just the fact that it IS high res, fix the animation problems?

2

One use for retopology is, as the name suggests, to create a new topology for a model. Maybe you have started by sculpting a model, or the model has poor topology for some other reason. The original models might work well for still images, but when animating a model, topology is important for controlling how the mesh deforms.

Retopo will also allow you to fairly easily place vertices on a surface. Let’s say you have made a head, and you are working on the eyes. A good way to make the mesh look good around the eye, is to use a sphere for the eye, and then place the outline of the eye on the surface of the sphere using retopo, this way you will get a smooth shape that matches the eye perfectly.

3

Because none needs the 100,000-vertices mesh (slow render, difficult to work with, huge file) they got from sculpting when they can have the exact same render with a 10,000-vertices mesh.

The idea is to make a quick and dirty high-poly mesh and then “capture” the topology, i.e. the paths of vertices that give the mesh its shape and that are just enough to get a perfect render.

4

Thank you for explaining it to me.

Quick follow up; so you’re telling me everyone who sculpts a hi-res model, re-models the same object/character again?

5

Hi-resolution model is good for baking a normal map, which can reduce rendering time significantly.

6

in the world of sculpting, it is common practice to sculpt from a cube, or else a very simple base mesh, then retopo to get a decent mesh.