Convert Bitmap to TX Format for Arnold 3ds Max

Converting bitmap textures to Arnold's native TX format optimizes render performance, reduces memory usage, and speeds up texture loading. Arnold's TX (Tiled EXR) format uses tiled texture architecture and built-in compression, making it significantly more efficient than standard bitmap formats like JPG, PNG, or TIF. This guide covers both automatic and batch conversion methods available to 3ds Max users.

Why Convert to TX Format

The TX format was designed specifically for production rendering pipelines. Unlike standard bitmap formats, TX files use a tiled texture structure that allows Arnold to load only the portions of the texture needed for rendering, rather than loading entire textures into memory. This tiled architecture provides several advantages:

Memory Efficiency: TX format uses tiled loading, so Arnold only keeps relevant texture tiles in memory. For a 4K texture, this can reduce memory footprint from several hundred megabytes to just what's actively being rendered. Large texture sets that might require 8GB of RAM with standard formats can run efficiently with TX conversion.

Faster Rendering: Tiled texture access is faster than sequential file reads. Arnold's texture cache system can rapidly access specific tiles, reducing render time, especially on complex scenes with many textures and displacement maps.

Compression: TX format applies lossless compression (by default), reducing file size without quality loss. This also decreases storage requirements and improves file transfer speeds when submitting jobs to render farms.

Mipmap Support: TX files include built-in mipmaps for different resolution levels, improving rendering quality for distant objects or highly angled surfaces without requiring separate mipmap files.

Understanding Arnold's Texture Cache System

Arnold uses a 512MB default texture cache to manage loaded textures during rendering, as described in the Arnold texture system documentation. This cache stores frequently accessed texture tiles. When your scene's total texture memory exceeds cache size, Arnold evicts less-used tiles to make room for new tiles, managing memory automatically.

With bitmap formats, this eviction process happens more frequently because entire textures are cached as single units. TX format's tiled approach means:

Only necessary tiles occupy cache space
More textures fit within the same cache size
Cache hits are more frequent for tiled access patterns
Out-of-core rendering becomes feasible for very large texture collections

The default 512MB cache can be adjusted in Arnold render settings if needed, but converting to TX format usually makes cache adjustment unnecessary.

Method 1: Auto-Convert in 3ds Max 2022 and Later

3ds Max 2022 introduced automatic TX conversion directly in the 3ds Max interface. This method is the most straightforward approach for most workflows.

Step-by-step auto-conversion process:

Open your 3ds Max project containing the bitmap textures you want to use with Arnold
Navigate to the Render Setup dialog (press F10 or go to Rendering > Render Setup)
In the Render Setup window, locate the Arnold Renderer section
Find the Textures tab within Arnold Renderer settings
Enable the "Auto-convert Textures to TX" option (or similar naming, depending on 3ds Max version)
Specify an output directory where converted TX files will be saved
Configure any additional options such as compression level (if available)
Click "Apply" or "Convert"

3ds Max will scan all bitmap textures referenced in your scene and automatically convert them to TX format. The conversion happens in the background, and your original bitmap files remain unchanged. After conversion, Arnold automatically uses the TX files instead of the original bitmaps.

Important considerations:

Conversion only happens for textures actually used in the scene
Unused texture files in your project directories are not converted
The "Use Existing TX Textures" option appears after conversion, allowing you to switch between TX and original bitmaps
Conversion time depends on total texture resolution and quantity
Large texture sets (100+ high-resolution textures) may take several minutes

Method 2: Batch Conversion with txConverter.bat

For users on older 3ds Max versions or those who prefer command-line conversion outside 3ds Max, batch conversion using txConverter.bat provides flexibility for complex workflows. Mads Drøschler has created and maintained txConverter.bat, available on GitHub, which automates TX conversion for large texture collections.

Setting up txConverter.bat:

Download txConverter.bat from the GitHub repository (search for "txConverter.bat Mads Drøschler" or check Arnold's official documentation for the link)
Extract the script to a convenient location on your system
Open Command Prompt or PowerShell
Navigate to the script location
Create a batch file or run the command directly with texture file paths

Running the batch converter:

The basic syntax is:

txConverter.bat input_texture.jpg output_texture.tx

For multiple textures, create a batch process:

for %%F in (C:\textures\*.jpg) do txConverter.bat "%%F" "C:\textures\tx\%%~nF.tx"

This command processes all JPG files in the textures folder and outputs TX files to a tx subfolder, preserving original filenames.

Advantages of batch conversion:

Centralized control over all texture conversions
Easier to manage large texture libraries
Can be integrated into production pipelines
Works with any version of 3ds Max
Processes textures outside of 3ds Max, freeing the application for other work
Suitable for network-based or distributed conversion workflows

Batch conversion considerations:

Requires familiarity with command-line interfaces
Processing time can be substantial for thousands of textures
Disk space needed for output files (TX files are typically 30-50% smaller than originals, but still require temporary space)
Error handling requires monitoring command-line output

Supported Input Formats

Both conversion methods support standard bitmap formats:

JPG / JPEG (most common, good compression ratio)
PNG (lossless, preserves alpha channels)
TIF / TIFF (high quality, large file sizes)
OpenEXR (floating-point precision, already optimized but can be converted to TX)
Other formats supported by your Arnold installation

Using Existing TX Textures in Arnold

After conversion, 3ds Max presents the "Use Existing TX Textures" option in Arnold render settings. This toggle allows you to:

Switch between TX and original bitmap formats
Test rendering with TX files to verify quality
Revert to original bitmaps if needed for comparison
Mix TX and bitmap formats in the same scene

For production rendering, especially when submitting work to cloud render farms, ensure "Use Existing TX Textures" is enabled so the render farm accesses the optimized TX files rather than attempting to convert again.

Render Farm Considerations

When submitting 3ds Max scenes with converted textures to cloud rendering services, TX conversion provides significant advantages:

Faster Job Submission: TX files are typically 30-50% smaller than original bitmaps, reducing upload time to render farms. A scene with 2GB of bitmap textures might compress to 1-1.5GB of TX files.

Reduced Download Time: Render farm workers receive smaller texture packages, enabling faster job distribution across multiple render nodes.

Faster Render Execution: Since Arnold on the render farm uses the same TX format, no additional conversion occurs during rendering. Render nodes immediately access optimized textures, reducing initialization time.

Consistent Results: TX files ensure identical rendering on your local machine and on the render farm. No format conversions introduce subtle differences in texture appearance.

When preparing scenes for cloud render farms like Super Renders Farm, pre-converting textures to TX format reduces job processing time and improves overall turnaround. Many professional render farms recommend or require TX format for production workflows.

Troubleshooting Conversion Issues

Conversion Fails or Produces Invalid TX Files:

Verify source texture files are not corrupted by opening them in image editing software
Ensure sufficient disk space for output files
Check file permissions on source and output directories
Try converting a single file first to identify specific issues

TX Files Not Being Used:

Verify "Use Existing TX Textures" option is enabled in Arnold settings
Check that TX files are in the expected output directory
Confirm texture paths in the scene reference the TX files correctly
Review Arnold's error log for texture loading errors

Conversion Takes Too Long:

This is normal for large texture sets; processing 100+ 4K textures may take 30+ minutes
Consider batch conversion outside business hours or on a dedicated processing machine
For extremely large collections, distributed batch conversion across multiple machines is possible

TX File Quality Issues:

Verify compression settings match your quality requirements
Check if original texture quality was sufficient before conversion
Compare TX renderings with bitmap renderings to confirm fidelity

Optimizing Your Texture Workflow

Organize textures before conversion:

Create separate folders for different material types (fabric, metal, wood, etc.)
Use consistent naming conventions for easy identification
Remove unused textures before batch conversion
Document texture resolution and purpose for team reference

Document conversion settings:

Keep notes on compression settings used
Record conversion dates for texture library maintenance
Track which projects use converted TX files
Maintain backups of original bitmap files

Integrate with pipeline automation:

Automate TX conversion as part of your pre-render scene preparation
Create custom 3ds Max scripts to batch-convert textures on scene load
Set up folder monitoring to automatically convert new textures added to project directories

FAQ

Q: Is TX format loss of quality compared to original bitmaps? A: No. TX format uses lossless compression by default, preserving pixel-perfect quality. The only change is file organization and compression, not visual quality. Rendered results are identical.

Q: How much smaller are TX files compared to original bitmaps? A: Typically 30-50% smaller than original JPG or PNG files. A 200MB texture set might compress to 100-150MB in TX format. The actual reduction depends on texture complexity and original compression.

Q: Can I delete original bitmap files after converting to TX? A: Yes, once TX files are confirmed to work in your renders. Keep backups of original textures for archival purposes, but TX files can completely replace bitmaps in your active projects.

Q: Do I need to convert every texture? A: Textures actively used in scenes should be converted for optimal performance. Unused textures don't affect rendering and can remain in bitmap format. Focus on high-resolution textures used in close-up shots.

Q: Will TX conversion work with displacement maps? A: Yes. Displacement maps benefit significantly from TX format's tiled architecture, especially for high-resolution displacement data. The same conversion methods apply.

Q: Can older 3ds Max versions use TX files without auto-conversion? A: Yes. Older versions can load TX files if they're created externally using txConverter.bat or other command-line tools. Only the auto-conversion feature is unavailable in pre-2022 versions.

Q: What if I change a texture after converting to TX? A: You'll need to re-convert the updated bitmap to TX format. Update the original bitmap, then run conversion again, overwriting the previous TX file.

Q: Are TX files compatible with other render engines? A: TX files are Arnold-specific. Other render engines (V-Ray, Corona, Redshift) use different optimized formats. However, Arnold is the only engine that recognizes TX automatically.

Last Updated: 2026-03-18

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