Houdini 20.5 Nodes Geometry nodes

Labs ZibraVDB File Cache (Alpha) 0.2 geometry node

Performs compression and caching, or loading and decompression, of a VDB sequence to or from a single .zibravdb file.

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Since 20.5

As a part of the ZibraVDB for Houdini (Alpha) plugin, this node combines the functionalities of the Labs ZibraVDB Compress (Alpha) SOP and the Labs ZibraVDB Decompress (Alpha) SOP. It can compress/decompress both animated VDB sequences and static VDB geometries.

Similar to the File Cache SOP, this node operates in two modes:

The compression often achieves up to 97–99% reduction in VDB file size with minimal quality loss. The compression rate is adjustable for each VDB field, providing independent control over the quality and memory footprint of density, temperature, flame, and other standard or custom fields. Up to 8 float fields can be compressed simultaneously.

When reading back from disk, the entire sequence is loaded at once, with frames decompressed on demand using a frame index parameter. This significantly speeds up playback for high-resolution VDBs by eliminating the need to load one frame from disk at a time. Additionally, the total size of the data to be loaded is much smaller. The decompression occurs on the GPU and is extremely fast.

Tip

You may also compress SDF VDBs indirectly. Convert SDF VDBs to Fog VDBs before compression and back to SDF VDBs after decompression using the Convert VDB SOP.

Note

Vector VDBs currently cannot be compressed. This feature will be supported in the future. In the meantime, you can split vector VDBs to float VDBs using the VDB Vector Split SOP before compression. After decompression, merge the float VDBs back to vector VDBs using the VDB Vector from Scalar SOP. Please note that compressing vectors is not exactly the same as compressing vector components independently, so this current workaround may yield unexpected results.

Windows

ZibraVDB for Houdini (Alpha) is currently only supported on Windows.

Getting Ready

Acquire License Key

For the plugin to function, Houdini must be able to locate a valid ZibraVDB license on your machine.

  1. Please read the ZibraVDB Terms of Service.

  2. Visit ZibraVDB for Houdini (Alpha) to request a trial license.

  3. After receiving your license key, create a text file in a directory of your choosing and name it zibravdb_license_key.txt. Paste your license key into this text file and save it.

  4. Set up a Houdini environment variable named ZIBRAVDB_LICENSE_KEY and assign it the path to your license key file.

Tip

For example, if you saved the license key file to C:/Users/.../Documents/houdini20.5/zibra/, then you may add the following line to your houdini.env file:

ZIBRAVDB_LICENSE_KEY = C:/Users/.../Documents/houdini20.5/zibra/zibravdb_license_key.txt

You may also use the package mechanism to set environment variables.

Download ZibraVDB Core Library

The plugin also requires the ZibraVDB core library on the back end. (This library and its source code are proprietary to Zibra AI and, therefore, are not included directly in the open-source SideFX Labs package.) The plugin has a built-in method to download this core library, which only needs to be done once (per working environment).

  1. Press the Download Library button on any ZibraVDB node.

  2. In the pop-up window, confirm that you accept the ZibraVDB Terms of Service to proceed.

  3. The download will occur in the background and will typically complete within a few seconds.

  4. A second pop-up window will appear once the download is finished. The core library, ZibraVDBHoudiniBridge.dll, will be saved to $HOUDINI_USER_PREF_DIR/zibra/X_Y/. Alternatively, if the site-specific directory $HSITE is set, it will be saved to $HSITE/zibra/X_Y/.

About ZibraVDB

ZibraVDB is a cutting-edge VDB compression and real-time rendering technology developed by Zibra AI. The compression can currently achieve up to 97–99% reduction in VDB file size with minimal quality loss. The proprietary .zibravdb file format captures an entire VDB sequence in a single file, which can be loaded into applications such as Houdini or Unreal Engine, decompressed on the GPU in real time, and played back in the viewport at speeds significantly faster than native solutions.

For artists, this provides a memory-efficient, high-performance volumetric data pipeline that seamlessly integrates into existing workflows.

It significantly reduces storage costs, improves volumetric data I/O speeds, and ultimately makes it easier and more practical to share working projects and distribute final products containing high-fidelity volumetric effects.

ZibraVDB for Houdini, contributed by Zibra AI, is a SideFX Labs plugin that brings ZibraVDB’s compression, decompression, and accelerated playback capabilities into Houdini’s ecosystem.

Additionally, the compressed .zibravdb files can be used with ZibraVDB for UE. This empowers artists to bring stunning volumetric effects created in Houdini to Unreal Engine and render them efficiently as full 3D ray-marched volumes in real time.

Feedback and Support

If you have any questions, issues, or feedback, please reach out to ZibraVDB Support.

You can also contact SideFX Support and mention that the issue should be directed to the SideFX Labs team.

Parameters

Load from Disk

If on, loads and decompresses the .zibravdb file specified in File instead of cooking the input geometry.

Reload Cache

Forces a reload of the .zibravdb file from disk and refreshes the decompressed frame.

File

The file path which the compressed VDB geometry will be saved to or loaded from. The file extension must be .zibravdb. During caching, any missing directories in the path will be automatically created.

Caching

Cache

Render to Disk

Compresses the VDB geometry and saves it to disk.

Background Render

In a separate background process, compresses the VDB geometry and saves it to disk. This allows you to continue working in the current Houdini session.

Sequence

Valid Frame Range

Specifies whether to compress and render a single frame or a frame sequence of VDB geometry.

Start/End/Inc

The start frame (inclusive), end frame (inclusive) and frame increment, when Valid Frame Range is “Render Frame Range” or “Render Frame Range Only (Strict)”.

Save Filters

Delete Attributes

The list of attributes to delete before compression and caching. Separate multiple attributes with spaces. This list applies to all attribute classes.

Delete Groups

The list of groups to delete before compression and caching. Separate multiple groups with spaces. This list applies to all group types.

Number of Casts

The number of attribute casts to perform before compression and caching. Each combination of attribute class and precision requires a separate multiparm entry.

Class

The class of attributes to cast to the specified precision.

Attributes

The list of attributes to cast to the specified precision. Separate multiple attributes with spaces.

Precision

The target precision for the attributes.

Compression Settings

Quality

The output quality of the compressed VDB geometry. Higher values result in fewer artifacts but larger file sizes. The file size increases exponentially as this value increases.

Use Per Channel Settings

If on, you can override the output quality of individual channels (i.e. fields), such as density, temperature, flame, etc. Any channel not specified below will still use the value of Quality.

Number of Channels

The number of channels (i.e. fields) to override.

Channel Name

The name of the channel (i.e. field) to override.

Channel Quality

The output quality of the compressed VDB geometry for the specified channel (i.e. field). This overrides the value of Quality for this particular channel.

Advanced

Save

Render with Take

Specifies which take to render with.

Scripts

Pre-Render Script

The script to run before any rendering.

Pre-Frame Script

The script to run before each frame.

Post-Frame Script

The script to run after each frame.

Post-Render Script

The script to run after all rendering.

Download Library

Downloads the core library for all ZibraVDB nodes. You only need to press this once (per working environment).

Examples

Tip

When viewing in Houdini’s Help Browser, please copy the example file’s URL to a regular browser to proceed with the download.

See also

Geometry nodes