Sculpting Techniques

Modo provides you with the ability to sculpt your models in a variety of ways and then texture them easily in one integrated environment and work non-linearly. This flexibility means you can model, sculpt, apply a basic texture, and then go back and model some more. As with all the tools in Modo, the functions are deeply integrated and take advantage of the core functionality to provide an intuitive and powerful set of options.

Combining a natural blend of 2D- and 3D-painting techniques, you can select a brush and begin painting in any viewport. Modo tries to determine the best options automatically when painting or sculpting, but there are a couple requirements necessary to get the best results. Modo's default interface provides a Paint layout tab, which is dedicated to painting, sculpting, and Vertex Map-editing tools, and a toolbox with the related tools.

You may benefit greatly from using a pressure-sensitive tablet when painting or sculpting in Modo, but this is not a strict requirement. (Most users find tablets to be a more natural way to work with the pen-based input instead of using a mouse.) The additional control from the pressure-sensitive stylus can provide a greater degree of precision and subtlety when modeling and texturing creations.

Sculpting Types

Modo has three types of sculpting: Mesh, Image-Based, and Multi-Res. Mesh sculpting uses the raw geometry. It is great for building out rough forms, but it is not as good at producing fine details. Image-based sculpting uses image maps for producing fine details. You can use either grayscale displacement images (where shades of gray push vertices in or out a specific distance based on their shade) or 32-bit vector images that allow not only in-and-out movement but side-to-side movement as well for cavities and undercuts. With image-based sculpting, you can generate fine details for models, but it does have some limitations (such as the need for fixed-resolution bitmap images and the related UV map). Finally, Modo offers multiresolution (Multi-Res) sculpting, which requires no images or UV mapping, for you to sculpt on multiresolution meshes. This method provides the flexibility and immediacy of mesh sculpting and the detail of image-based sculpting. The only drawback is the greater amount of resources necessary to calculate the multiresolution meshes.

Each type of sculpting has its own set of requirements. If you understand the methods, you can determine how to best apply them for their intended purposes.

Mesh Sculpting

Mesh sculpting is rather simple in Modo. To do mesh sculpting, all that you need is some geometry and a brush. You can activate any of the sculpting tools available in the Paint layout and start sculpting. For more information in sculpting tools, see Using Sculpting Brush Tools. Modo doesn't care if the model is straight polygons or a subdivision surface. It pushes and pulls the vertices as you wish. To create complex sculptured meshes easily, you can apply the Remesh tool to distribute the polygons. Once applied, more details are added to your mesh. For more information, see Automatic Retopology Tool.

Note:  When sculpting raw polygons, you can quite easily generate grossly non-planar polygons, which can cause rendering errors. You can generally resolve these errors by triangulating the model or by applying subdivision surfaces to the mesh.

Benefits: Easy setup, can work across multiple surfaces, not limited by material assignment, CPU-friendly, low memory requirements
Disadvantages: No high-frequency detail, only works on vertices

Image-Based Sculpting

Modo's displacement-mapping methods require subdivision surface models: regular models or Pixar's Catmull-Clark versions. These models also need an image map applied to all surfaces that you wish to sculpt. For best results with displacement maps, use 16-bit images. For vector displacement-based images, use 32-bit formats (such as EXR). The images also need to be applied to the surface with the Shader Tree by using a UV map. You can specify this in the Texture Locator. Defining a UV map can be a tedious process, but Modo provides tools, such as UV Unwrap and UV Relax, that make it easy for you to produce quality results in a short amount of time.

Once you meet these requirements, you can begin sculpting as you would for straight mesh sculpting. Activate a brush and a tip from the toolbox and then start sculpting a model.

Benefits: Good high-frequency detail, low polygon requirements until render time
Disadvantages: Setup required with UVs, video card display limitation for openGL viewports

Multi-Res Sculpting

Multiresolution sculpting is simpler to set up than image-based sculpting, but you do need to do it properly. First, this method requires the Pixar Catmull-Clark Subdivision Surfaces geometry. If your model has regular SubDs, then you must convert them to be Catmull-Clark subdivision surfaces. To do this:

1.

Select all the SubD surfaces, press Tab to disable SubD mode, and then press Shift+Tab to apply the Catmull-Clark SubDs.

2.

Next, select the Multi-Res checkbox in the Mesh Item's properties.

Additionally, you may introduce some additional subdivision levels with the Subdivision Level option.

After you meet these requirements, you can activate a sculpting tool and begin to sculpt. With this method, you can add or remove subdivision levels by pressing the + and - keys on the numeric keypad and can go through the subdivision levels using the Ctrl+Plus and Ctrl+Minus keys.

With multiresolution sculpting, you can also use sculpting layers, which allow you to have multiple sets of displacement vectors in a mesh. For more information, see Creating Sculpting Layers

Benefits: Easy setup, no images or UV maps, powerful editing methodology
Disadvantages: Requires more RAM and processing power than other methods, result must be frozen to export to other apps

Customizing Brushes

Like the rest of the Modo toolset, the paint and sculpting tools are modular and composed through the Tool Pipe. If you are not familiar with the Tool Pipe, you don't have to use it. You can do 3D painting and sculpting with the provided tools. The standard tools fulfill most, if not all, of your modeling and texturing requirements.

The Tool Pipe brings flexibility and power to the painting system. It has components that you can add together to create custom tools. These components include the paint tool, a brush tip, custom inks, nozzles, and even falloffs. For basic painting and sculpting, you only need a tool and a brush tip. You can add or remove the inks, nozzles, and falloffs depending on the intended effect. With the Tool Pipe you can combine a variety of components to create customized tools specific to your creative needs.