Luckily, there is a very easy way for to take your existing model, and build on it to create a new model that is exactly the same or very close to it and still have correct topology. We will do this by using the 'Freefrom Polydraw' function that is built into 3ds max. For this example, we will be working with a simple cushion.
First, right click on your model and change it to an editable polygon. This won't work unless it is an editable polygon.
Once it is an editable polygon, open the 'Freeform' tab that is next to the 'Graphite Modeling Tools', then click on the Polydraw tab. In here, click ' Draw On: ' and change it to surface. Then pick the model that you are going to be retopologizing. Then click on the topology tool, and click new object.
Now you can start drawing grids on the existing model. Once the grids join, they will form polygons. You can draw multiple grids at a time, and then later bridge them together. Once you have covered they whole model, you can add support edges (which are discussed in my previous tutorial) and a turbo smooth modifier to get a model with clean topology and less polygons.
