Textures - settings

These settings control how texture files are handled by Arnold.

 

Filtering

 

Accept Unmipped Textures

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-mipmap

If a texture map file is not natively mipmapped (e.g. a JPEG file), enabling this option will trigger the generation of a mipmap on demand. The output will be stored in memory and put in the global texture cache. This mipmap generation increases render time, specially for scenes with many high resolution textures. To avoid this performance slowdown, it is recommended to use texture file formats that natively support mipmapping (such as TIFF and EXR), where the mipmaps are preprocessed before the render and stored in the file. This preprocessing can be done with the maketx utility.

Filter

The type of texel interpolation used for texture lookups. Bicubic produces the highest quality, at a slight increase in render time.

Diffuse Blur

Controls the amount of blur in texture look-ups for Diffuse rays.

Glossy Blur  

Blurring of texture for lookups by glossy rays. When using the Cook-Torrance BRDF, textures are automatically blurred and this parameter is ignored.


Tiling

Accept Untiled Textures

High-resolution untiled texture maps are very inefficient to render, because they must be loaded entirely into memory as soon as the renderer needs to access the first texel. When this flag is disabled, any attempt at loading an untiled 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, specially 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.

Use Existing .tx Textures

If an untiled texture is requested (e.g. concrete.jpg) but a .tx file with the same filename is found (e.g. concrete.tx), the renderer will load the .tx file instead.

Caching

Enable

Enables texture caching.

Cache Size (MB)

The maximum amount of memory to be used for texture caching. Arnold uses a tile based cache with a LRU (Least Recently Used) type algorithm, where the least recently used tiles are discarded when the texture caches is full.

Max. Open Textures

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.