Maketx is a command-line utility to convert images to tiled, MIP-mapped textures, similar to txmake in Pixar Renderman. It is part of OpenImageIO (http://www.openimageio.org) and was developed by Larry Gritz at Sony Pictures Imageworks.

Benefits of Using .TX

The first benefit is that you are assured of having mipmaps and tiles. These will dramatically improve time to the first pixel, overall render time, and allow using a smaller texture cache. This should be considered mandatory, with the possible exception being don't use .tx for the few images you are actively modifying if you don't want to wait for them to be constantly converted to .tx every time you make a change.

The previous level you could get from non-tx files that you saved with tiles and mipmapping. The second level of benefit is only with .tx files and that involves maketx adding metadata that lets Arnold make more optimizations, such as being able to detect duplicate textures and only loading a single copy into memory or detecting constant color images, such as an all-black UDIM, and instead of storing all those black pixels in memory Arnold can special case that.

_{An example of mipmap image storage. The first image on the left is shown with filtered copies reduced in size.}

_{The maketx command with verbosity, converting from a tif to a tx}

Usage

 maketx [options] file... 

eg: maketx -v -u --oiio --checknan --filter lanczos3 path/to/fileIn.tif -o path/to/fileOut.tx

When pre-processing your texture files with maketx make sure you add the -- oiio flag which will generate TX files optimized for Arnold that can render even faster by forcing the tile size to be optimal for OpenImageIO ( 64x64). It also stores channels interleaved (RGBARGBA...) making them faster to read and enables constant color detection: if the image is a constant color it will convert it to a tiny single color .tx file. Additional metadata and an image hash (fingerprint) are embedded by default. The fingerprint lets OIIO detect duplicate images (not tiles) when opening new files. Generally using maketx will result in better texture I/O performance than using txmake.

If the output color space is not the same bit depth as input color space, then the data format needs to be set to the proper bit depth using the -d option.

The best workflow is to always generate .tx files using maketx as the last step before rendering and use those .tx files just for rendering. This will ensure the best performance. Also, ensure that your textures are in linear color space before converting them with maketx. No information is lost when converting High Dynamic Range images to the .tx format.

Parameters

^{_{Pepe model by Daniel M. Lara (Pepeland).}}