Textures (settings) - Arnold User Guide
Texture Auto Generate TX
Enables automatic generation of TX textures from source textures. This requires options.texture_use_existing_tx to be enabled. TX files will be generated in the same folder as the source texture, unless options.texture_auto_tx_path is set, in which case all new TX files will be generated into that folder (preserving existing folder tree to avoid collisions). This is enabled by default in Arnold, although different plugins might choose to disable it by default. This feature might cause problems if multiple render farm nodes are trying to convert the same textures in the same target folder at the same time, resulting in potential crashes, corrupt textures, and low performance.
The environment 'ARNOLD_AUTO_GENERATE_TX' can be used to override the texture_auto_generate_tx option. The current allowed values are 'when_outdated' and 'never'.
Texture Auto TX Path
Path in which all new TX files will be auto generated.
Auto-convert Textures to TX
Automatically generates tiled and mipmapped TX textures. The TX texture will be linearized according to the colorspace attribute.
Use Existing TX Textures
Allows you to use texture formats like .exr or .jpg in the plug-in, but .tx textures for rendering. When Use Existing .tx Textures is enabled, the plug-in checks for .tx versions of the textures referenced in the scene and exports them to Arnold. For example, if a file node references a .jpg, then the plug-in will check for a .tx version of that file. If the plug-in finds a .tx version, it exports the .tx file name to Arnold instead of the .jpg.
The .tx file must be located in the same directory as the requested source texture and have the same name with the exception of the file extension. For instance, if "foo/bar/floor.png" is requested and "foo/bar/floor.tx" exists then "floor.tx" will be used. Arnold will ignore any requested colorspace conversions when the .tx file is used since it assumes the .tx will have the colorspace transform baked in.
Accept Unmipped
High-resolution unmipped texture maps are very inefficient to render because the highest resolution level must be loaded into memory regardless of the distance rather than a lower resolution level. When this flag is disabled, any attempt at loading an unmipped file will produce an error and abort the renderer.
Auto-tile
If a texture map file is stored in scanline mode (e.g. a JPEG file), enabling this option will trigger the generation of tiles on demand. The output will be stored in memory and put in the global texture cache. This process increases render time, especially for scenes with many high-resolution textures. To avoid this performance slowdown, it is recommended to use texture file formats that natively support tile mode (such as TIFF and EXR). You can create tile textures with the maketx utility.
Tile Size
This is the size of the tiles when using auto-tiling. Bigger values mean less frequent texture loads but use more memory.
Accept Untiled
If a texture map file is not natively mip-mapped, the render will give an error unless this option is checked.
Max Cache Size (MB)
The maximum amount of memory to be used for texture caching.
Max Open Files
The maximum number of files that the texture system keeps open at any given time to avoid excessive closing and re-opening of files when caching individual texture tiles. Increasing this number may result in slightly better texture caching performance. On the other hand, if this value is higher than the maximum number of concurrently open files supported by the operating system (e.g. Linux vs Windows), some texture lookups may fail and return red. This is set by default to 0, which means that the maximum number of texture files that can be simultaneously opened is automatically computed by Arnold using a heuristic that tries to guess what the optimal number would be for each particular machine. We expect that the majority of users will be able to leave this at 0 and get the best performance.