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# Frequently Asked Questions
### Customer FAQ
What is VFX Grass?
VFX Grass is a high-performance, GPU-driven grass system for Unity that uses VFX Graph to render and animate large amounts of grass in real time.
Which render pipelines does VFX Grass support?
VFX Grass supports both HDRP and URP.
What is its main advantage?
Performance. VFX Grass is designed to render very dense grass with minimal CPU cost, and it can easily handle over 1 million instances.
How does VFX Grass perform on very large terrain?
Very well. The size of the terrain by itself is not what matters most for performance. What matters more is how much grass is actually being rendered on screen at once, your grass density, your camera view, your render pipeline, and your target resolution.
As an extreme stress test, VFX Grass was pushed to 10 million grass instances and still ran at around 80 FPS in 4K, inside the Unity Editor, with 107 draw calls. That is a far heavier test than most real game scenes would ever use.
It is also important to understand that 80 FPS at 4K in the Editor is already very strong performance. The Unity Editor adds overhead, and 4K resolution is much more demanding than 1080p or 1440p. In a real game build with practical grass density and normal gameplay camera distances, performance is typically much more favorable.
In short, VFX Grass is built to handle extremely large environments efficiently, and the tested results show that it remains highly performant even under unrealistic worst-case conditions.
Why does VFX Grass perform so well?
VFX Grass is built with performance as a core priority. It combines GPU-based rendering with multiple optimization systems so only the grass that actually matters gets rendered efficiently.
It uses frustum culling to avoid rendering grass outside the camera view, occlusion culling to reduce unnecessary rendering when grass is blocked from view, and distance-based fading with LOD behavior to reduce the cost of grass farther away from the camera.
Because the system is GPU-driven, it can handle a very large number of grass instances much more efficiently than traditional object-based approaches. This allows VFX Grass to keep dense scenes looking rich while maintaining strong performance.
Is it easy to set up?
Yes. VFX Grass is designed for a fast and simple setup, with quick tools to create the manager, set up the required cameras, and add a new grass VFX object.
Can I customize the look of the grass?
Yes. VFX Grass includes controls for grass count, mesh LODs, textures, alpha clipping, scale variation, colors, gradients, noise, wind, and motion.
Does VFX Grass support wind animation?
Yes. VFX Grass includes a procedural wind system with controls for direction, speed, strength, detail wind, and wind highlights.
Does it support interactive or reactive grass?
Yes. VFX Grass supports dynamic interaction using motion capture and masking workflows, allowing the grass to react to movement and other effects.
Can the grass match the ground color?
Yes. VFX Grass supports ground-color-based blending, as well as gradient and noise-based color options for both the top and bottom of the grass.
Is it flexible for different art styles?
Yes. VFX Grass works well for both stylized and more natural-looking grass, with customizable textures, colors, wind behavior, and mesh settings.
What is included in the asset?
VFX Grass includes sample content, grass textures, grass meshes with LOD support, shaders, VFX assets, and editor tools to speed up setup.
Who is VFX Grass for?
VFX Grass is ideal for Unity users who want dense, animated, high-performance grass in HDRP or URP without relying on traditional terrain grass workflows.
### Support FAQ
What does the Grass Manager do?
The Grass Manager is the core controller of the system. It sets up the helper cameras, manages the render textures, and sends the required data to the grass VFX.
Why does VFX Grass use multiple cameras?
Each camera captures a specific type of data that the grass system uses, such as projection, masking, motion, and normal information.
What is the difference between HDRP and URP setup?
Both are supported, but they handle some data differently. HDRP supports albedo buffer capture directly, while URP uses an additional normal capture setup with a custom renderer.
Why is my grass not showing up?
This is usually caused by an incomplete setup. Check that the Grass Manager is created, the helper cameras are assigned, the grass VFX object exists, and your layer masks are set correctly.
Why are the colors or ground blending not working correctly?
Check your color mode settings and make sure the required render texture inputs are being captured correctly. In HDRP, ground color blending depends on albedo capture. In URP, the setup depends on the normal capture workflow.
Why is wind not affecting the grass the way I expect?
Check the wind direction, wind speed, wind strength, detail wind values, and highlight settings in the grass settings component.
Why is interaction or motion response not working?
Make sure the motion capture setup is active and that the relevant layers and render textures are configured correctly.
Do I need a different setup for URP?
Yes. URP uses an additional normal capture camera and a custom renderer asset as part of the setup, so make sure those parts are correctly assigned.
Can I add multiple grass VFX objects under one manager?
Yes. The Grass Manager can refresh and manage a list of child grass VFX objects.
What should I check first if something looks wrong?
Start by checking pipeline setup, layer masks, helper camera creation, render texture assignments, and whether the grass VFX list has been refreshed and settings applied.