Texture Mat


Overview

Texture Mat is a sample showing how to Automatically texture a model using the Python API and Command Line Tools.The data used in the demo are:

  • texture_mat.py script that does most of the work
  • create_compositing_network.py which uses the python API to generate a custom SBS file for selecting what material goes on what part
  • batch_utilities.py, demo_cmd.py and demos.py for utility functions
  • Mesh_MAT.FBX and a set of SBS files in the texture_mat directory

The output will be put in the texture_mat/_outputs directory

In order to run the demo, make sure python is installed and in your path environment and that the substance python api is installed. Then go to the samples directory and run:

python texture_mat.py

It will now invoke a set of calls to different command line tools to generate three different sets of maps for the model

Details

The mat model is set up as three parts, the head, the body and the base.

The UV set is laid out in a single uv tile:

There are three materials set up for the model, leather_fine_touch.sbs, steel_battered.sbs and terracotta_glossy.sbs. They are all set up with wear driven by geometry maps such as occlusion, curvature, position etc.

Process setup

In texture_map.py there is a section the with the setup

The bake setup specifying what maps to bake and what command line parameters to pass to the baker and how to name the maps. The only special case here is the color-from-mesh baker where we set the color source to be the material id's.

# All bakes needed for generating materials together with 
# additional command line options and 
# what input images they should be bound to when rendering
maps_to_bake = [('ambient-occlusion', [], 'ambient-occlusion'), 
                ('curvature', [], 'curvature'),
                ('position', [], 'position'),
                ('normal-world-space', [], 'normal-world-space'),
                # Bake color from mesh with submesh id as color source (2)
                ('color-from-mesh', ['--use-lowdef-as-highdef', 'true', '--color-source', '2'], 'color-id')]

The following part maps part names to colors coming out of the color id baker so we can detect what texel belongs to what part of the object.

# Dictionary mapping sub mesh to a compositing color
submesh_to_color_mapping = {'head' : '0,1,0',
                            'body' : '0,0,1',
                            'base' : '1,0,0'}


In this section we define what sets of maps we want to bake. Different sbs files and settings are assigned to the different mesh parts in the three different setups.

# SBS assignments for all variations to render together 
# with what sub graph to render and parameters to set for each material 
output_texture_variations = { 'Rusty' : 
                                {'head' : ('steel_battered.sbs', 'steel_rusty', {'rust_spreading' : [.16],
                                                                                 'steel_color' : [1,.88,.60]}),
                                 'body' : ('steel_battered.sbs', 'steel_rusty', {'rust_spreading' : [.16],
                                                                                 'steel_color' : [.98,.81,.75]}),
                                 'base' : ('steel_battered.sbs', 'steel_rusty', {'rust_spreading' : [.16]})},
                              'Leather' : 
                                {'head' : ('leather_fine_touch.sbs', 'leather_worn', {}),
                                 'body' : ('leather_fine_touch.sbs', 'leather_worn', {}),
                                 'base' : ('leather_fine_touch.sbs', 'leather_worn', {})},
                               'Painted_Terracotta' : 
                                {'head' : ('terracotta_glossy.sbs', 'painted_terracotta', {}),
                                 'body' : ('terracotta_glossy.sbs', 'painted_terracotta', {}),
                                 'base' : ('terracotta_glossy.sbs', 'painted_terracotta', {})}
                            }

Baking

The first thing happening when running the texture_mat.py script is maps being baked for the mesh. It will use the maps_to_bake definition to generate a set of calls to sbs_baker.

When done the _output directory will contain the following maps:

 

Compositing Network

In order to create specific maps for each texture variation we are going to create a new substance file representing the specific assignments and parameters. The heavy lifting for this process happens in the file create_compositing_network.py. It takes as input the substance files and specific settings for each material color and generates a custom texturing substance file using the substance python api.

The output for the leather material looks like this:

In the center is a multi material blend node that has the different materials associated with their corresponing color from the sub mesh. The materials imported also have their properties from the configuration set on them to make sure there can be multiple instances of the same material with different parameters in one texturing network. There are also inputs for ambient occlusion for color id, ambient occlusion and curvature wired into the networks.

Cooking

In order to render maps from these compositing networks the generated sbs files they need to be cooked to sbsar files. This happens through the sbscooker command line tool.

Rendering

The final stage is rendering the maps for each variation using sbsrender. The command line to sbsrender binds the right textures and renders out the correct maps.

With these maps we can render the final result