Why does the External Render folder get so large in ZBrush?

The External Renderer folder in ZBrush can grow quite large over time because it stores the images and data generated when sending renders to an external renderer such as KeyShot.

When you render externally, ZBrush does not only create the final rendered image. It also generates temporary and support files that are required to transfer scene data, materials, geometry, and render passes to the external application.

Over time, especially if you:

• Render frequently
• Use high resolutions
• Work with complex materials or large scenes
• Perform multiple test renders

the accumulated data in the External Renderer folder can consume significant disk space.

Managing Folder Size

You can safely delete old files inside the External Renderer folder if they are no longer needed. These files are not required for ZBrush to function and will be recreated automatically when needed.

To reduce file size growth in the future, you may also:

• Lower render resolution when testing
• Reduce unnecessary render passes
• Avoid repeated high-resolution test exports

Folder Locations

ZBrush 2026.1.0 and Newer

Beginning with 2026.1.0, the External Renderer folder is located inside your user asset directory:

Windows
C:\Users[YourUserName]\AppData\Roaming\Maxon\ZBrush_[HashValue]\ExternalRenderer

macOS
/Users/[YourUserName]/Library/ApplicationSupport/Maxon/ZBrush_[HashValue]/ExternalRenderer

ZBrush 2026.0.1 and Older

Windows
C:\Users\Public\Public Documents\ZBrushData20XX\ExternalRenderer

macOS
/Users/Shared/ZBrushData20XX/ExternalRenderer

Note
The version number in ZBrushData20XX corresponds to your installed version.

If disk space is a concern, you may also consider relocating your ZBrush user asset directory using Preferences > Asset Directory, which allows you to store these files on a secondary drive.