Mesh Fill

Summary

Mesh Fill is a GPU-accelerated simulation that drives particles to move through mesh volumes or surfaces using a density-guided algorithm. The simulation guides particles through density fields generated from input geometry, creating organic movement patterns as particles navigate the space.

Supports both mesh-based and volume-based inputs with automatic voxelization for mesh geometry. You can control whether particles move through the entire interior volume or along the surface boundary, with adjustable radius controlling movement constraints. Filtering parameters allow smoothing of the velocity field for more uniform or organic particle motion. The Seed page controls optional particle spawning from density regions when enabled.

Mesh Fill outputs the moving point cloud and optionally generates trail geometry showing particle movement paths through the volume. The trails visualize the exploration patterns as particles navigate the density field over time. The simulation includes standard playback controls (initialize, start, play) for controlling the fill progression. This makes Mesh Fill ideal for creating organic growth animations, volumetric exploration effects, particle flow visualizations, or animated particle-based mesh representations.

Parameters

Page: Mesh Fill

Time Step Timestep – Controls simulation speed per frame (higher values = faster filling).
Switch to Volume Input Switchtovol – Use 3D texture input instead of mesh geometry for density field.
Normalize Input Mesh Normalizeinputmesh – Scale input mesh to unit size before voxelization.
Max Axis Resolution Maxaxisres – Voxel grid resolution for mesh-to-volume conversion (higher = more detail).
Ray Direction Mode Raydirmode – – Method for determining ray directions when voxelizing meshes.
Constant constant
Inside Sphere insidesphere
Ray Direction Raydir – – Direction vector for ray casting when Ray Direction Mode is set to Constant.
Ray Direction Raydirx
Ray Direction Raydiry
Ray Direction Raydirz
Precision Precision – – Texture precision for density field.
16-bit float 16bit
32-bit float 32bit
Fill Surface Only Fillsurface – Restricts particles to surface boundary instead of filling entire volume.
Radius Radius – Particle spacing radius controlling packing density (smaller = tighter packing).
Filter Scale Filterscale – Multiplier for density field filtering iterations.
Filter Size Size – Blur kernel size for density field smoothing.
Initialize Initializepulse – Pulse to reset simulation and prepare density field.
Start Startpulse – Pulse to begin filling simulation from initialized state.
Play Play – Toggle continuous simulation playback.

Page: Seed

Spawn From Density Spawn – Enables spawning new particles from density field during simulation.
Seed Count Seedcount – Number of seed particles to spawn per frame when spawning enabled.
Seed Seed – Random seed for particle spawn positions.
Max Attempts Maxattempts – Maximum spawn position attempts before giving up (prevents infinite loops).

Page: Trails

Enable Trails Enabletrails – Enables trail geometry generation showing particle movement paths.
Length Length – Maximum trail length in frames (history buffer size).
Filter Type Filtertype – Smoothing filter for trail curve (gaussian, catmull-rom, etc.).
Edge Distance Filterdist – Distance metric for edge filtering along trail curves.
Effect Effect – Smoothing effect strength (0 = no smoothing, 1 = full effect).
End Points Fixed Endpointsfixed – Prevents smoothing from moving trail endpoints.

Page: Lookup

Lookup Trails Lookuptrails – Samples the trails texture onto input geometry.
Apply Blur Applyblurtrails – Applies blur filtering to the trails texture before sampling.
Pre-Shrink Preshrinktrials – Resolution reduction before applying blur for trails texture.
Filter Size Sizetrials – Blur kernel size for trails texture smoothing.
Lookup Filled Volume Lookupfilledvol – Samples the filled volume texture onto input geometry.
Output Inverted Outputinverted – Also outputs the inverted filled volume texture.
Apply Blur Applyblurvol – Applies blur filtering to the filled volume texture before sampling.
Pre-Shrink Preshrinkvol – Resolution reduction before applying blur for filled volume texture.
Filter Size Sizevol – Blur kernel size for filled volume texture smoothing.
Lookup Offset Lookupoffset – – Offset applied to lookup coordinates when sampling textures.
Lookup Offset Lookupoffsetx
Lookup Offset Lookupoffsety
Lookup Offset Lookupoffsetz
Lookup Scale Lookupscale – – Scale applied to lookup coordinates when sampling textures.
Lookup Scale Lookupscalex
Lookup Scale Lookupscaley
Lookup Scale Lookupscalez
Debug Debug – – Selects which texture to visualize for debugging.
None none
Trails trails
Filled Volume filled
Inverted Filled Volume inverted

Page: Common

Free Extra GPU Memory Freeextragpumem – Free memory that has accumulated when output memory has grown and shrunk.

Inputs

Input 0 POP – Mesh to Fill
Input 1 TOP – Volume to Fill
Input 2 POP – Seed

Outputs

Output 0 TOP – Trails
Output 1 TOP – Filled Volume
Output 2 TOP – Inverted Filled Volume
Output 3 TOP – Velocity
Output 4 TOP – Volume
Output 5 POP – Seed
Output 6 POP – Trails
Output 7 POP – Mesh