Issue:

How to convert bitmap textures to .TX format for rendering with Arnold in 3ds Max.

Once converted, Arnold can then load the more memory-efficient TX textures at render time automatically (you do not need to swap out all existing bitmaps used within the scene manually for each material).

Causes:

Converting existing 3ds Max scene texture bitmaps from JPG, PNG, TIF or other types of formats to a TX format can speed up renderings and overall memory efficiency.

As stated on the Arnold for 3ds Max User Guide: Textures page:

“Arnold’s texture system can load one tile at a time, as needed, rather than having to wastefully load the entire texture map in memory. This can result in faster texture load times, as texels that will never be seen in the rendered image will not even be loaded. In addition to the speed improvement, only the most recently used tiles are kept in memory, in a texture cache of default size 512 mb (can be tuned via options.texture_max_memory_MB). Tiles that have not been used in a long time are simply discarded from memory, to make space for new tiles. Arnold will never use more than 512 MB, even if you use hundreds, or thousands of 4K and 8K images.”

Solution:

To convert existing texture bitmaps to TX format inside of 3ds Max

As of 3ds Max 2022, the ability to auto-convert texture bitmaps used in an existing scene has been added to the Render Setup menu for Arnold. To use this option:

1. Go to the Rendering > Render Setup > Arnold Renderer tab.
2. At the bottom of the Arnold Renderer tab, open the Textures section.
3. Check the Auto-convert Textures to TX box. This will convert all existing bitmaps used in the scene to the TX format, leaving the original files and the newly-created TX textures in the same folder.
4. Upon rendering, Arnold will use the newly-created TX files at render time.

Use TX textures when rendering with Arnold in 3ds Max

1. After the bitmap conversion process, make sure to keep the new TX files in the same folder as the current bitmaps used in the scene.
2. In the 3ds Max Rendering menu, go to Render Setup.
3. Select the Arnold Renderer tab, and open the Textures roll-out menu. 
4. Check the “Use Existing TX Textures” button. At render time, this will load the more memory-efficient TX files, and eliminate manually swapping out all the current bitmaps (JPGs, PNGs, TIFs, etc.) used in the scene materials for the new TX textures.

To batch-convert bitmap files to TX format outside of 3ds Max

3ds Max artist and programmer Mads Drøschler has created several MAXScript-based utilities to help 3ds Max users batch-convert their existing bitmap files to the TX format. The scripts can be downloaded from the following GitHub repository and used to convert bitmaps to TX by using the following steps:

Download and save the Scene Converter Scripts

1.  Visit Mads’ GitHub page: Arnold Scene Converter Scripts 3ds Max (registration to GitHub may be required).
2. Click the link “ArnoldScripts”.

3. Click the link “txConverter.bat”.

4. Click the Raw button. This will open a browser window displaying the GitHub code.

5. Right-click in the browser window.
6. Choose Save as…

Important Note: If unable to right-click the open area to Save As, copy the code to Notepad and save the file with the name “txConverter.bat“.

7. Ensure the file extension is a BAT format (*.bat). If there is any additional format listed after the file name, remove it. The file should be named “txConverter.bat”.

8. Save the txConverter.bat file to: C:\users\<username>\AppData\Roaming\Microsoft\Windows\SendTo.

Use the Windows Explorer Send To function

1. Once in the \SendTo folder, open Windows Explorer and navigate to the desired folder containing the texture bitmaps.
2. Select the bitmaps to be converted. (Note: If any errors appear, reduce the number of bitmaps selected. The script should be able to convert 100 selected images at a time, depending on memory):

3. Right-click to bring up the Windows Properties menu.
4. Choose Send To and click the txConverter.bat entry.

5. A Windows MS-DOS command panel will then appear, showing the progress of the image conversions.

6. When finished, the TX files will appear alongside the original bitmap textures.

In addition, Mads has created a TX Pipeline Video explaining how to use these utilities.

Note: If the txConverter.bat file cannot find the MakeTx.exe program, go to the Arnold Downloads page and  download and install the latest MaxToA version.
 

Source: Autodesk