Ansys Rocky DEM 2026: Beginner Guide, Tips & Fixes

Ansys Rocky DEM 2026: Beginner Guide, Tips & Fixes

The first time I tried to simulate a conveyor belt carrying ore particles, I quickly realised that conventional CFD and FEA tools were the wrong instruments for the job. Particles aren't fluids. They don't flow continuously and smoothly — they collide, pile up, bounce, fracture, and interact with equipment surfaces in ways that require a fundamentally different simulation approach.

That approach is the Discrete Element Method, and Ansys Rocky is the tool that implements it at a professional engineering level. What struck me most, when I first sat down with Rocky properly, was how naturally it mapped to the physical intuition of bulk material handling. You define particles. You define equipment geometry. You define motion and gravity. Rocky works out how every particle moves, collides, and behaves — across tens of millions of particles if your hardware supports it — and gives you the kind of insight into bulk material behaviour that simply isn't available from any other simulation approach.

If you're trying to understand what Ansys Rocky actually is, how to access it, what it costs, which platforms it supports, and how to get productive with it as quickly as possible — this guide covers everything you need, in plain language, from real experience.

What Is Ansys Rocky DEM Software

Ansys Rocky is a Discrete Element Method (DEM) simulation software for modelling the behaviour of bulk materials and granular flows. DEM is a numerical method that tracks every individual particle in a simulation — modelling its position, velocity, rotation, and interactions with other particles and with equipment surfaces — to predict the collective bulk behaviour of the material as a whole.

Where CFD simulates fluid as a continuous medium and FEA simulates solid structures as a continuum, DEM treats bulk materials as collections of discrete, interacting bodies. This makes it uniquely suited for problems where the discrete, particulate nature of the material matters — which is most industrial bulk material handling situations.

Rocky is used across:

• Mining and minerals processing: crusher wear analysis, conveyor belt loading, screen efficiency, mill charge motion
• Agriculture: grain handling, harvester performance, seed coating and blending
• Pharmaceutical manufacturing: tablet coating, powder blending, capsule filling, granulation
• Food processing: product handling, sorting, and mixing of granular food materials
• Cement and building materials: kiln and mill simulation, bulk handling and transfer
• Energy: coal handling systems, biomass fuel processing
• Chemical engineering: reactor design with solid catalysts, fluidised beds, powder conveying

The Rocky software originated in Brazil at the ESSS (Engineering Simulation and Scientific Software) company, was acquired by Ansys, and is now fully integrated into the Ansys simulation ecosystem with direct coupling to Ansys Fluent (for CFD-DEM), Ansys Mechanical (for structural loads from particle impact), and Ansys optiSLang (for design optimisation).

Ansys Rocky DEM Features: What the Software Actually Delivers

Rocky's feature set covers the full range of bulk material simulation requirements. Here is a structured breakdown of the most important capabilities.

Particle Modelling Capabilities

• Flexible particle shapes: spheres, polyhedra, fibres, shells, and custom-shaped particles defined from CAD geometry; this is one of Rocky's strongest differentiators, as many DEM tools are limited to spherical particles
• Particle size distributions: define realistic particle populations with statistical size and shape distributions that match physical sieve analysis data
• Breakage models: simulate particle fracture under impact and compressive loads; predict size reduction in crushing and grinding processes
• Sticking and cohesion: model cohesive and adhesive particle behaviour for moist, sticky, or electrostatically charged materials
• Flexible fibres: simulate elongated flexible particles such as sugar cane, wood chips, and straw that deform during handling

Contact and Physics Models

• Multiple contact models: Hertz-Mindlin, linear spring-dashpot, and advanced elasto-plastic contact models for different material types
• Rolling resistance: models particle shape resistance to rolling, essential for realistic packing and flow of non-spherical particles
• Thermal DEM: heat transfer between particles and between particles and equipment surfaces; important for drying, cooling, and heated processing applications
• Electrical charging: triboelectric charging of particles for electrostatic separation and powder handling applications

GPU-Accelerated Solving

Rocky's GPU-accelerated solver is one of its defining technical features. While traditional DEM solvers run on CPUs, Rocky's multi-GPU solver can process tens of millions of particles simultaneously — a scale that would be prohibitively slow on a CPU-only solver. For industrial-scale simulations of real equipment with realistic particle populations, GPU acceleration is not a luxury; it is a practical necessity.

Integration with Ansys Fluent: CFD-DEM Coupling

The coupling between Rocky DEM and Ansys Fluent for CFD-DEM simulation is one of the most powerful capabilities in the combined Ansys ecosystem. It allows simultaneous simulation of both the fluid phase and the particle phase, with full two-way interaction:

• Fluid drag forces: fluid drag forces on particles from the Fluent CFD solution
• Volume fraction effects: particle volume fraction effects on the fluid from the Rocky DEM solution
• Heat transfer: heat transfer between fluid and particles
• Applications: includes pneumatic conveying, fluidised beds, cyclone separators, and spray drying

Ansys Rocky 2025 R2 and 2026: What's New

The 2025 R2 release introduced:

• GPU performance: Enhanced GPU solver performance for very large particle counts
• Breakage models: Improved breakage model accuracy for ore crushing applications
• Fluent coupling: Better Fluent coupling stability for dense particle-fluid flows
• Flexible fibres: Expanded flexible fibre model capabilities

The 2026 release builds on these improvements with:

• Multi-GPU scaling: Expanded multi-GPU scaling for larger industrial simulations
• CAD shapes: Improved particle shape import from CAD geometry
• Post-processing tools: Enhanced post-processing tools for particle trajectory and collision analysis
• optiSLang integration: Better integration with Ansys optiSLang for equipment design optimisation workflows
• Python API: Updated Python scripting API for workflow automation and parametric studies

Ansys Rocky Price and Access Options

Ansys Rocky License Cost

Ansys Rocky does not carry a publicly listed price. Commercial licences are sold through Ansys and its authorised resellers with pricing negotiated based on configuration, the number of GPU tokens for HPC simulation, and the specific modules required. Rocky's GPU-based licensing model means that cost scales somewhat with the computational resources you need for your simulation scale.

For organisations running large-scale mining or materials processing simulations, Rocky is often most economically accessed as part of a broader Ansys simulation suite bundle rather than as a standalone product.

Ansys Rocky Student Version

Ansys Rocky offers a student version at no cost for educational use. The student version provides access to Rocky's core DEM simulation capabilities with model size and GPU usage limitations appropriate for academic work. It is entirely adequate for learning DEM simulation fundamentals, completing academic projects, and building genuine Rocky competency.

To access the Rocky student version:

• Step 1: Visit ansys.com/academic/students
• Step 2: Create a free Ansys account using your student or personal email
• Step 3: Navigate to the Rocky student product section — it may be listed separately from the main Ansys Student suite
• Step 4: Download the installer and follow the installation instructions
• Step 5: Activate using your Ansys account credentials at first launch

Ansys Rocky Free Download and Trial

The legitimate free access routes are:

• Student version: through the Ansys academic portal as described above
• Free Trial: through the Ansys Rocky product page on ansys.com; provides full commercial access for a limited evaluation period

To request the commercial trial:

• Step 1: Visit the Rocky product page on ansys.com
• Step 2: Select the trial or "Try Ansys" option
• Step 3: Complete registration with your work or institutional email
• Step 4: Download and install following the provided instructions

Platform Support: Windows, Mac, and Compatibility

Ansys Rocky on Windows 11

Ansys Rocky is fully supported on Windows 11. The application, its GPU-accelerated solver, and the post-processing environment all function correctly on Windows 11 in current releases.

GPU hardware matters significantly for Rocky. Recommended system configuration:

• GPU: NVIDIA GPU with CUDA support is required for GPU-accelerated simulation; RTX or Quadro series cards provide the best performance. A minimum of 6 GB GPU VRAM is practical for most simulations; 12 GB or more is preferred for large particle count simulations.
• RAM: 16 GB minimum; 32 GB or more recommended for large simulation datasets
• CPU: Modern multi-core processor; used for pre- and post-processing tasks
• Storage: SSD strongly recommended; Rocky simulation output files can be large, and fast I/O improves post-processing responsiveness significantly

Without an NVIDIA CUDA-capable GPU, Rocky simulations run on the CPU only, which is significantly slower for anything beyond small test cases. For serious DEM simulation work, NVIDIA GPU hardware is essentially a prerequisite.

Ansys Rocky on Mac

There is no native macOS application for Ansys Rocky. The software is Windows and Linux only. Mac users who need Rocky access have these options:

• Virtual Machines: Windows virtual machine — Parallels or VMware Fusion on Intel Mac can run Rocky's interface, but GPU pass-through to CUDA for the simulation solver is unreliable in virtualised environments, which severely limits simulation performance
• Remote Desktop: Remote desktop to a Windows workstation — the most practical approach for Mac users; run Rocky on a dedicated Windows machine with appropriate GPU hardware accessed remotely
• Linux HPC: Linux HPC cluster — Rocky has a Linux version suitable for HPC deployment, commonly used for large industrial simulations on institutional computing clusters

Ansys Rocky on Windows 7

Windows 7 is not supported for current Rocky releases. The software requires Windows 10 or Windows 11 and runtime dependencies unavailable on Windows 7. The installer will fail on Windows 7.

Ansys Rocky Getting Started: A Beginner's Roadmap

Rocky has a more accessible learning curve than many might expect for a specialist DEM tool. The interface is well-organised around the physics of the problem — particles, geometry, motion, simulation, results — and the workflow follows a logical sequence that mirrors how you would physically think about a bulk material handling problem.

Ansys Rocky for Beginners: Where to Start

My honest recommendations for a productive first week:

• Start simple: Start with a simple chute or hopper simulation. A single-material particle flow through a chute onto a flat surface is the cleanest first problem. It involves all the core workflow steps — particle definition, geometry, simulation settings, solve, post-processing — without the complexity of multi-material populations or equipment motion.
• Use spheres first: Use spherical particles for your first simulation. Rocky supports complex particle shapes, but spheres are computationally fastest and simplest to configure. Build your workflow competence on spheres before adding shape complexity.
• Check setup with a small particle count: Run a small particle count first to check your setup. Before committing to a simulation with 500,000 particles, run the same setup with 10,000 particles using a short simulation time. This confirms your geometry, contact model, and boundary conditions are correct before spending GPU hours on a full run.
• Understand timestep: Understand the timestep before your first real run. The simulation timestep in DEM must be sufficiently small relative to the contact duration between particles. Rocky has an automatic timestep recommendation tool — use it, and understand why the value it suggests matters.
• Watch the fill process: Watch the particle fill process before post-processing results. Rocky's 3D viewer shows particles being generated and falling into the geometry in real time. Watching this for the first minute of a simulation tells you immediately whether your particle generation rate, geometry, and gravity settings are correct.

How to Use Ansys Rocky: The Core Workflow

• Define domain: Define the simulation domain — set up the simulation environment including gravity direction, time settings, and simulation duration
• Import geometry: Import or create geometry — import equipment surfaces (conveyor belts, hoppers, crushers, screens) from CAD files (STL, STEP, or other formats); define wall material properties
• Define particles: Define particles — specify particle shape, size distribution, density, and contact material properties
• Set up injection: Set up particle injection — define how particles enter the simulation: injection rate, velocity, starting position, and particle generation duration
• Define motion: Define motion — specify any moving equipment surfaces (conveyor belts, rotating drums, vibrating screens) with their motion parameters
• Configure contact model: Configure contact model — select and configure the contact model appropriate for your materials (Hertz-Mindlin is the default for most applications)
• Set timestep & output: Set timestep and output frequency — confirm the simulation timestep and specify how frequently particle position data is saved
• Run the simulation: Run the simulation — execute the DEM solve; monitor progress through the real-time particle viewer and the simulation progress panel
• Post-process results: Post-process results — review particle flow patterns, velocity distributions, force chains, wear maps, and energy dissipation data

Ansys Rocky Tutorial and Documentation Resources

Official Guides and User Manual

Rocky's documentation set is comprehensive:

• Ansys Rocky User Manual: the primary reference document covering all features, particle models, contact models, motion types, and post-processing tools; available through the Ansys Customer Portal
• Getting Started Guide: a structured introduction to the Rocky workflow covering the interface, a first simple simulation, and core result interpretation
• Rocky Tutorial collection: worked examples covering conveyor loading, hopper discharge, screen efficiency, and mill charge motion; available through the Ansys Customer Portal and Learning Hub
• Ansys Learning Hub: structured Rocky courses covering DEM fundamentals and application-specific workflows; free for Student users and trial users
• CFD-DEM Coupling Guide: specific documentation for the Rocky-Fluent coupling workflow; essential reading for pneumatic conveying and fluidised bed applications

Recommended Learning Path

• Step 1: Complete the Getting Started Guide from beginning to end — do not skip this
• Step 2: Run the hopper discharge tutorial from the tutorial collection, following each step manually
• Step 3: Modify the tutorial to use a different particle shape and compare the discharge behaviour
• Step 4: Set up a simple conveyor belt simulation from scratch using geometry you create or import
• Step 5: Explore the post-processing environment: create velocity colour maps, particle trajectory plots, and force chain visualisations on a completed simulation
• Step 6: Attempt a Rocky-Fluent coupled simulation on a simple pneumatic conveying geometry once you're comfortable with standalone Rocky

Ansys Rocky Tips for Better DEM Simulation Results

Particle Definition Tips

• Match size distributions: Match your particle size distribution to physical sieve analysis data where possible. A DEM simulation using a realistic particle size distribution produces significantly more accurate bulk flow predictions than one using a uniform particle size, even if the median particle size is correct.
• Optimise particle count: Use the minimum particle count that captures the key physics. More particles give better statistical accuracy, but simulation time scales with particle count. For equipment design comparisons, a relative comparison between design variants at lower particle count is often more valuable than an absolute prediction at high particle count.
• Use non-spherical shapes: Don't use perfectly spherical particles if shape matters. Rocky's non-spherical particle shapes — polyhedra, rounded polyhedra — produce realistic angle of repose, packing density, and flowability behaviour that spheres cannot replicate. For equipment where bulk flow pattern matters (hopper discharge, screen efficiency), non-spherical shapes are worth the additional computational cost.

Contact Model Tips

• Calibrate models: Calibrate your contact model against physical bulk tests before using simulation results for design decisions. The angle of repose test, the flow factor test, and the impact plate wear test are all well-established calibration experiments. A few hours of calibration significantly improves simulation predictive accuracy.
• Apply rolling resistance selectively: Use rolling resistance appropriately. Rolling resistance is not a physical contact property — it's a correction factor that accounts for particle shape effects in spherical particle simulations. If you're using non-spherical particle shapes, rolling resistance is typically not needed.

Simulation Performance Tips

• Maximise GPU utilisation: Maximise your GPU utilisation. Rocky's GPU solver is significantly faster than the CPU solver for large particle counts. Ensure Rocky is configured to use your NVIDIA GPU, and close other GPU-intensive applications during simulation runs.
• Manage output frequency: Set output frequency thoughtfully. Saving particle position data every simulation timestep produces enormous output files. For most analyses, saving data every 0.01–0.1 seconds of simulation time is sufficient. Only increase output frequency if you need to analyse very rapid collision events.

Ansys Rocky Keyboard Shortcuts

Ansys Rocky Error Fix: Resolving the Problems Beginners Hit Most

Ansys Rocky Resolve Errors: Common Issues and How to Fix Them

Problem: Simulation starts but particles immediately escape through geometry walls

This is one of the most common first-run issues and almost always indicates a geometry problem.

• Check surface orientation: Check that your geometry surfaces are correctly oriented — in STL format, surface normals must face the correct direction (inward for containing walls). Reversed normals allow particles to pass through surfaces as if they don't exist.
• Verify scale: Check the geometry scale — a geometry imported in millimetres but interpreted as metres will be 1,000 times smaller than intended, and particles will appear enormous relative to the equipment
• Check for gaps: Verify that the geometry is watertight with no gaps at seams or edges; gaps allow particles to escape at the boundaries between surfaces

Problem: GPU solver is not being used; simulation runs on CPU only

• Verify GPU detection: Confirm your NVIDIA GPU is detected by Rocky — check the solver settings panel for GPU device options
• Update drivers: Verify that NVIDIA CUDA drivers are installed and up to date on your Windows system
• Check VRAM: Check that your GPU has sufficient VRAM for the simulation size; if VRAM is insufficient, Rocky falls back to CPU automatically
• Confirm solver settings: Confirm Rocky's solver settings are configured to use GPU rather than CPU in the simulation configuration panel

Problem: Simulation timestep warning — timestep too large

• Use automatic tool: Use Rocky's automatic timestep recommendation tool and accept the suggested value; the recommended timestep is calculated based on your contact model stiffness and particle properties
• Don't increase manually: Do not manually increase the timestep beyond the recommended value to speed up simulation — this causes numerical instability and produces physically incorrect particle behaviour
• Adjust stiffness if needed: If the recommended timestep is producing unacceptably long simulation times, consider whether your contact stiffness can be reduced without significantly affecting your bulk behaviour of interest; softer contact models allow larger timesteps at the cost of some contact accuracy

Problem: Particle pile-up at injection point rather than flowing into the domain

• Check injection velocity: Check that the particle injection velocity and direction are set correctly; particles injected at zero velocity or in the wrong direction will pile up immediately
• Verify throughput capacity: Verify that the geometry at the injection point is not restricting flow; an injection rate that exceeds the geometry's throughput capacity will produce a growing pile at the entry
• Check gravity direction: Check that gravity is correctly configured — incorrect gravity direction or magnitude produces unrealistic bulk flow behaviour

Problem: Rocky crashes or runs out of memory during large simulations

• Check particle count: Check total particle count — each particle requires memory allocation; very large particle counts can exhaust both GPU VRAM and system RAM
• Reduce domain or particles: Reduce the simulation domain size or particle count to a level your hardware can support; for industrial-scale simulations requiring very large particle counts, Rocky's multi-GPU or HPC cluster deployment is necessary
• Maximise available memory: Close other applications to maximise available memory during the simulation run

Problem: Licence checkout failure on startup

• Check licence manager: Confirm the Ansys Licence Manager service is running — open Windows Services and check status; restart if stopped
• Verify internet: For Student version, confirm an active internet connection is available; student licences require online validation at launch
• Review firewall rules: Check that your firewall is not blocking licence manager communication on the default ports

Is Ansys Rocky Worth Learning in 2026

My honest assessment: for anyone working in bulk material handling, mining, pharmaceutical manufacturing, food processing, or any other industry where granular material behaviour matters, Ansys Rocky is the most capable and best-supported DEM simulation tool available. The combination of flexible particle shape definition, GPU-accelerated solving at industrial scale, and tight integration with the rest of the Ansys ecosystem for coupled CFD-DEM and structural analysis sets it apart from alternatives in the market.

The GPU dependency is a real hardware consideration — you need an appropriate NVIDIA GPU to use Rocky at its full potential. But given that modern engineering workstations routinely include capable NVIDIA GPUs, this is less of a barrier than it once was. For students using the student version, a mid-range gaming GPU is sufficient for academic-scale simulations.

The documentation is comprehensive, the tutorial resources cover the most important application types, and the community of users across mining, pharmaceutical, and process industries provides a substantial body of shared knowledge to draw on.

My rating: Good — clearly and without reservation. If bulk material simulation is relevant to your work, Rocky is the right tool. Start simple with a hopper or chute case, calibrate your contact model against physical data, use the GPU solver from day one, and Rocky will give you insights into bulk material behaviour that no other simulation approach can provide.