GSOPs 2.9 (Gaussian Splatting Operators) for SideFX Houdini 20.5 and 21.0

Upgrade Guide for Existing Users

Our licensing options have changed. Learn more.

As a part of our transition to CG Nomads, we have removed the renderer submodule dependency and decoupled example data from the repository to reduce its size, improve maintainability, and streamline installation. Therefore, we recommend you perform a fresh clone and follow the installation instructions as normal.

Where Magic Meets Reality

Add ✨ to your Gaussian splatting scenes with GSOPs — the most versatile Gaussian Splats editing toolset!

Gaussian splatting is a radiance field technology that turns photos and videos into high-quality 3D content with view-dependent effects and fast rendering. Gaussian Splatting Operators (GSOPs) is a plug-in for SideFX Houdini that grants artists total creative control over Gaussian splatting scenes.

GSOPs includes a real-time viewport renderer, example files, and a suite of digital assets for efficient import, editing, and export of 2D and 3D Gaussian splatting content.

Among its many capabilities, GSOPs is effective at isolating objects, eliminating noise and "floaters", deforming and animating splat models, composing scenes, meshing and relighting, performing feature analysis, and generating synthetic training data capable of delivering high-fidelity results with complex view-dependent effects.

Developed by David Rhodes and Ruben Diaz, GSOPs is now hosted under CG Nomads.

Check out GSOPs on LinkedIn and YouTube for more examples.

🥉 GSOPs won 3rd place in the H20 SIDEFX LABS Tech Art Challenge.

💬 Join us on Discord!

GSplat Source

Motivation

Houdini's powerful, data-efficient architecture makes it the go-to platform for procedural content production across many industries. Its flexible and extensible design empowers users to tackle complex challenges at the right level of abstraction, focusing on problem-solving rather than low-level technicalities.

This unique combination of flexibility and ease of use is especially valuable in the rapidly evolving field of Novel View Synthesis. It enables quick prototyping, testing, and refinement of new workflows, keeping pace with the latest research. Additionally, it provides a direct path for innovations to transition into real-world applications within a well-established, production-ready solution.

SideFX, the developer of Houdini, fosters innovation through its "Labs" initiative. This incubator allows for the iteration of new tools and workflows before they become mainstream. Similarly, GSOPs provides a dedicated playground for Novel View Synthesis, enabling users to craft new workflows that closely align with the final visual result while prioritizing a creative and enjoyable process.

Support Us

We're passionate about the potential of editable radiance fields in SideFX Houdini and we're eager to continue pushing boundaries. If you believe in this initiative or have benefitted from GSOPs, please consider donating.

Studio Licenses

Need support, private modifications, or commercial usage? Custom site licenses tailored to your studio’s needs are available upon request. Contact us at gsops.project@gmail.com for more information.

Installation

Clone this repository (use the develop branch for the latest and greatest).

[Using Git CLI] git clone https://github.com/cgnomads/GSOPs
[Using GitHub Desktop] Clone repository with URL: https://github.com/cgnomads/GSOPs.git

Automatic

Install and configure the GSOPs Houdini package by opening the hip/gsops_installer.hip file in Houdini, selecting the INSTALL_GSOPS node and clicking INSTALL.
<img width="548" alt="419229706-0c526dae-0ed9-4ab0-b986-9924f29c1481" src="https://github.com/user-attachments/assets/a0a08d0a-f6ea-491b-9419-a2e9e0fc706b" />
The installer will ask if you want to download sample data. Select "Yes" if you're interested in exploring our example content (recommended).

Manual

Copy the packages directory from the cloned repo location to your Houdini user preferences directory.
For each version of Houdini you want to use with GSOPs, change the "GSOPS" environment variable in the .json to your GSOPs clone location (e.g., GSOPs_20.5.json or GSOPs_21.0.json).
[Optional] Change the GSOPS_USER_DATA_DIR value as you see fit. This is where GSOPS configuration data will be stored--it needs to be a writeable location!
[Optional] Download sample data using the GSOPs shelf button.

Early Access Supporters

Activate your license using the GSOPs shelf button.

GSOPs Shelf

Getting Started

If you chose not to download sample data during installation, you should do that now via the GSOPs Shelf.
Open a few example scenes from the hip directory. Use these to validate your installation and better understand Gaussian splatting workflows.
For accurate color results, disable OpenColorIO in the viewport.
Disable viewport lighting and enable smooth shading. The Gaussian Splats Source node has a "Set Viewport Settings" button for your convenience. If you use this, set gamma in the color correction toolbar to 1.0. This button will also set the viewport renderer to use OpenGL, rather than Vulkan (required for live viewport compositing, see Edit->Preferences->3D Viewports->Renderer).
The Gaussian Splats Source SOP (i.e., the "render" node) does not currently have an output. This means it must exist at the end of your network.

Notes

Please be kind. We love innovating and learning, and we want you to benefit from this project.
GSOPs is only supported for Houdini 20.5 and 21.0.
Linux is not officially supported.
Please adhere to the SideFX Houdini License Agreement.
GSOPs can generate Gaussian splat training data, but it cannot train models. If you want to train models locally, please see 3D Gaussian Splatting for Real-Time Radiance Field Rendering, Postshot, or Brush (a great option for Mac users).
If you're interested in what you've seen and would like to discuss innovation/R&D collaboration opportunities, please contact us.
GSOPs is developed in our personal time and is provided as-is.

GSOPs Nodes

GSOPs is packed with features. For more information regarding any of the nodes shown above, please check the wiki and reference the built-in help cards.

[NEW] Houdini 21 Native Gaussian Splatting Interoperability

Houdini 21 has native Gaussian Splatting, but SideFX uses different attribute data conventions. Use the Gaussian Splats Convert SOP to convert between GSOPs and Houdini's native conventions.

[EARLY ACCESS] Support for Compressed Splats

In addition to .ply, import .splat and .spz file formats.

[EARLY ACCESS] Configurable Viewport Renderer

Unlock "live compositing" (traditional geometry and splats with proper depth sorting), "depth" and "worldPos" render modes.

[EARLY ACCESS] Gaussian Splats Histogram

Plot and edit splats in histogram space based on any floating point attribute. This provides a fun and intuitive way to apply targeted edits to your scene.

[EARLY ACCESS] Gaussian Splats Enhance

Add feature attributes to your splats, generate and/or improve normals, and add ambient occlusion and roughness approximations. These attributes can now be used by the Gaussian Splats Relight IBL node.

[EARLY ACCESS] Gaussian Splats Sharpen

Sharpen splats using optional mask attribute (e.g., from feature attributes).

[EARLY ACCESS] Support for Solaris & Karma

We now provide a Gaussian Splats Import LOP node to simplify rendering and relighting Splats in Solaris. Additionally, the Gaussian Splats Evaluate Spherical Harmonics has been updated to bake spherical harmonics to the color attribute (v@Cd) for raytracing. Check out the solaris.hip example to learn more.

[EARLY ACCESS] Gaussian Splats Mirror

Mirror your splats while preserving proper view dependent effects (spherical harmonics).

Support for 2DGS

The Gaussian Splats Import SOP now accepts 2DGS models!

Coarse Meshing

GSOPs 2.5 introduced dependency-free coarse meshing for 3D Gaussian Splatting. Coarse meshes are an effective "sparse node graph" for spl

GSOPs

Install / Use

README