HeatVolume-Unity: High-Performance Volumetric 3D Thermal Visualization

A high-performance 3D Heatmap Visualization system developed in Unity 6, specifically designed for Digital Twin applications (such as intelligent grain storage). It transforms discrete sensor data into immersive, fluid-like thermal volumes using CPU parallel processing and custom Raymarching.

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🚀 Key Features

• Parallel IDW Computing Core: Powered by the C# Job System (IJobParallelFor), distributing Inverse Distance Weighting (IDW) interpolation across all CPU cores. It is highly optimized for performance-sensitive environments like WebGL.
• Voxel Rendering Pipeline: Instead of traditional mesh-based interpolation, this system generates a dynamic Texture3D voxel grid, eliminating visual banding and artifacts.
• Advanced Raymarching Shaders:
  • Dual Mode Rendering: Supports both smooth organic "Rainbow" gradients and industry-standard 20-level precise discrete color banding.
  • Fluid Turbulence: Integrated 3D Simplex noise and time-based offsets to simulate the rising "heat haze" and atmospheric turbulence of high-temperature zones.
  • Visual Fidelity: Implements screen-space dithering to eliminate sampling layers and HDR glowing for critical hot spots.
• Industrial Layout Support:
  • Square Granary: Automatic matrix-based cubic grid generation.
  • Circular Silo: Parametric cylindrical distribution based on ring/radius settings.
• Data Snapshot System: Capability to capture and compare thermal states (e.g., "Before" vs "After" ventilation) for historical data analysis.

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🛠 Technical Architecture

1. The Algorithm: Parallelized IDW

The system treats every voxel in the $Texture3D$ as an independent calculation unit. The Job System calculates the weighted temperature influence of all nearby sensors: $$f(x) = \frac{\sum_{i=1}^{n} w_i(x) \cdot t_i}{\sum_{i=1}^{n} w_i(x)}$$ Where the weight is defined as $w_i(x) = \frac{1}{d(x, x_i)^2 + \epsilon}$.

2. Implementation Pipeline

1. Parsing: Deserializes sensor coordinates and real-time temperatures from JSON data.
2. Mapping: Spawns physical sensor proxies and aligns them within the normalized volume bounds.
3. Job Processing: Fills a NativeArray<Color32> with interpolated thermal data.
4. Buffer Upload: Updates the Texture3D GPU resource in a single frame.
5. Raymarching Pass: The URP shader samples the texture and performs volumetric integration with custom color mapping.

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📦 Getting Started

Requirements

• Unity Version: Unity 6 (or 2023.3+)
• Render Pipeline: Universal Render Pipeline (URP)

Installation & Usage

1. Clone the repository and open the project in Unity.
2. Attach the HeatVolumeManager_CPU.cs script to an empty GameObject.
3. Assign a material using either HeatRaymarching.shader or HeatRaymarching_Gradient.shader.
4. Load your JSON sensor data into the Real Data Text File slot.

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🎨 Visual Tuning

Parameter	Function
Step Size	Controls sampling density. Lower values improve quality at the cost of performance.
Noise Scale	Adjusts the granularity of the thermal fluid pattern.
Glow Intensity	Adjusts the HDR brightness for areas exceeding defined high-temperature thresholds.
Opacity	Overall transparency of the thermal cloud.

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