The Documents of Stage Hands

Texturing A Dyntopo Character

Introduction

SHThere are many ways in which texturing dense geometry can effectively be achieved, follow is a summary of two versatile techniques.
  • The first method should be quite familiar, as it makes use of a tried and tested process that has been widely implemented across 3D packages. It is also a popular method used when creating animated characters.
  • The second method is somewhat newer and relates specifically to static characters. Although Blender is the application used in this example other software packages might have similar features, for achieving a similar result. This documentation focuses mainly on the second method.

Reducing a Dense Polycount

Regardless of what your final output may be, for example a still frame, an animation or a game character, we first need to consider how to reduce the excessive amount of geometry that is created while sculpting a character. This is necessary in order to keep your 3D application responsive enough when working with a model in the viewport.
Texturing a model requires realtime feedback particularly for cloning out seams and painting the texture.

Method 1 : Modelled and Subdivided

If you have created your sculpted model by subdividing with a multires modifier, then there is not much you need to consider with regards to polycount reduction as your character’s edge loops should already have been modelled in the appropriate positions.

Method 2 : Dyntopo Tesselation

On the other hand, if your model has been sculpted with Dyntopo and your model is intended for animation you will need to retopologize the model in order to reduce it’s polycount.

This example, however, focuses on generating a model for a still image and as a result the model’s underlying topology is not as important, as the model will not need to deform for animation. As such, retopologizing a model can be used to achieve polycount reduction for static characters but it is not always necessary, and the following method should be considered particularly when dealing with time constraints and still images.

Methodology :

  • 1. Duplicate the High Res model.
  • 2. Decimate the duplicate and Apply the modifier.
  • 3. UV Unwrap the decimated model.
  • 4. Apply a Shrinkwrap Modifier to the realtime/decimated model targeting the original high poly model. Often, 3D artists will choose only to bake a Normal map instead of following this step. It is still possible to use a Normal map at this stage but combining a Normal map and this method will reveal a far greater degree of detail in your model thereby matching the Sculpted model more accurately, however, this is achived without the system overhead from a dense polycount during runtime.
  • 5. Add a Multires Modifier that subdivides the realtime model at rendertime.
  • 6. The realtime model can now be textured with multires (enabled or disabled) and which will subdivide the model respecting it’s UV layout.
The following image demonstrates the realtime model, with a diffuse texture. ngons

Methodology : Pros and Cons

Pros

The methodology in discussion for texturing characters with a dense polycount, can be very quick and efficient,
it’s quick because the main part of model density reduction ( or polycount reduction) is automated by the decimate modifier.

The efficiency of this method resides in being able to easily control the model’s polycount and ultimately how much detail or the Level of Detail (LoD) you want to work with in the viewport by means of the Shrink Wrap and MultiRes modifiers.

Setup is also quick and easy once you’ve used the Shrinkwrap modifier a few times.

Cons

The main drawback to using this method is that the model’s UV’s need to be layed out on decimated geometry. As decimation does not respect edge-loop placement (naturally), creating seams on a decimated model can tend towards a less desirable UV layout particularly when compared to the above mentioned method of retopologizing a model first.
However, the results might not be as problematic as you might imagine.
In the next section we compare the results of UV Layouts from a Retopologized models with that of Decimated models.