River Modeler is becoming a Stylized Water 3 extension
River Modeler was originally released in early 2024 with the goal of being a standalone river creation tool that could be used independently of any specific water shader (including HDRP). It therefore included its own basic river Shader Graph to make this possible
In practice, however, this made the relationship between River Modeler and Stylized Water 3 less obvious than intended. The two assets are a very natural combination, but because River Modeler was presented as a standalone product, Stylized Water 3 users weren’t necessarily discovering it or realizing how well the two fit together. As a result, sales remained very limited, and thus development didn’t progress.
Meanwhile, Unity 6 introduced changes to VFX Graph that required maintaining separate implementations for different Unity versions. Dropping Unity 2022 support would have been the simplest solution, but this would also have removed support for customers using River Modeler with Stylized Water 2.
Instead, River Modeler will be rebuilt as a dedicated Stylized Water 3 extension. This also provides an opportunity to greatly refresh and improve its functionality, making it a truly next-generation tool.
Because these are significant changes, I believe it’s important to communicate them as early as possible. A notice has therefore been added to the current River Modeler asset page and documentation as well.
Slated improvements
- Job System & Burst: River generation will be converted to Unity’s Job System and Burst compiler, making interaction and rebuilding considerably faster (+2400%) and more responsive.
- Segmented river output: Instead of generating one large mesh for the entire spline, rivers will be split into multiple segments. This greatly improves culling and rendering performance for long rivers and makes the system better suited to streaming systems.
- AAA Audio Streaming: Audio emitters are pooled and streamed as the camera moves in the world. Instead of needing hundreds of Audio Source components, only a handful around the camera are used.
- Automatic VFX/SFX integration: VFX and SFX data will be generated alongside the river geometry itself, removing the need to set up separate components and processes.
- Automatic alpha blending at intersections: River intersections will automatically blend together (without flowmaps), making branching rivers much easier to create without manually adjusting opacity points.
All of these features have already been successfully prototyped! 
What remains the same
The core workflow and concepts of River Modeler aren’t going away:
• Built around the Spline system: Rivers will continue to use Unity’s native splines, making them easy to combine with other spline-based tools and scripts.
• Width and displacement controls
• 3D audio for streams and cascades.
• MicroVerse integration
• Pre- and post-rebuild events
What this means for existing River Modeler users
The new toolkit will be completely rebuilt, so an automatic component upgrade from the existing River Modeler will unfortunately not be possible. But it’ll be straightforward to set up again: add the component and assign the Spline Container and tweak a few things.
Some functionality will also change as part of the redesign:
• FBX export option will be removed. The original system generated a single mesh, which made FBX export practical. With segmented river output, this no longer becomes technically viable.
• Vertex color controls will be removed and replaced by dedicated foam controls that are better suited to Stylized Water 3.
The existing River Modeler asset will be deprecated once the new extension is ready. This does not mean that existing users are left behind. The support channels will remain open, and critical patches (if needed) can be downloaded there.
A 20% upgrade discount has already been available for Stylized Water 3. A gracious upgrade discount will be offered for the new River Modeler extension. It can be upgraded to for free if River Modeler was purchased within the 30 days before its release.
What won’t be included
River Modeler will remain focused on being a river creation extension rather than becoming another general-purpose spline/mesh tool like Spline Mesher already is.
As a result, some of the more advanced functionality found in Spline Mesher Pro - such as spline data caching, LOD generation or compressed meshes - won’t be included.
Keeping the extension focused also allows it to remain reasonably priced as an addition to Stylized Water 3.
What’s still being worked out
A few details aren’t finalized yet, including:
• Pricing, free upgrade period and upgrade discounts for existing River Modeler users.
• I’m also investigating functionality that can trace paths through terrain and automatically generate splines with cascades and branching sections.
• A 2nd processing pass that performs depth/collision raycasts, for bumps and collision particles, is conceptualized.
TL;DR
River Modeler is being rebuilt from the ground up as an official Stylized Water 3 extension. The standalone approach made it harder to discover and maintain, while Unity 6 introduced additional compatibility challenges. The new version will retain the core river-building workflow while significantly improving performance, integration, effects and overall functionality.
Existing users can remain using this asset indefinitly and will be offered an upgrade discount to the extension.