In the realm of numerical simulation, 3D model quality plays a decisive role in obtaining reliable results. Holes and small geometric details often represent up to 80% of meshing time while generally being superfluous for analysis. Engineers waste precious hours manually simplifying these elements, particularly on non-parametric CAD models lacking construction history.
Automatic hole suppression is now a genuine optimization lever for engineering departments, drastically reducing preparation times and improving the quality of numerical simulations.
Table of contents
- Fundamentals and challenges of non-parametric CAD models
- Simplification stakes for different simulation types
- Traditional methods and their limitations
- CADfix DX for automatic hole suppression
- Workflow and integration in simulation processes
- Quantifiable and measurable benefits
- Industrial application cases
- Best practices and recommendations
Fundamentals and challenges of non-parametric CAD models
Non-parametric CAD models represent a major challenge for engineering teams. These geometries, often derived from neutral exchange formats such as STEP or IGES, lack construction history and parametric features, making their modification particularly complex.
Unlike native models that retain their construction tree, non-parametric models do not allow easy identification of geometric features such as holes, fillets, or chamfers. This lack of parametric information transforms each modification into a potentially risky operation for model integrity.
The main challenges associated with non-parametric models include:
- Absence of construction history making feature identification difficult
- Inability to use standard parametric modification tools
- High risks of topological errors during manual modifications
- Processing time considerably extended compared to native models
- Difficulties in maintaining geometric consistency after modification
In the context of preparation for numerical simulation, these challenges are amplified by the specific requirements of different solvers and the need to preserve certain geometric characteristics while simplifying others.
Simplification stakes for different simulation types
CAD model simplification represents a critical issue that varies considerably depending on the type of simulation planned. Each simulation discipline presents specific requirements in terms of geometric preparation.
For finite element analysis (FEA), eliminating holes and small details allows:
- Reducing mesh complexity and avoiding very small-sized elements
- Improving element aspect ratio in critical areas
- Significantly decreasing the total number of elements and therefore calculation times
- Avoiding geometric singularities that can distort analysis results
In the field of computational fluid dynamics (CFD), the issues are different:
- Elimination of geometries not relevant to fluid flow
- Optimization of fluid-structure interface surfaces
- Improvement of calculation convergence by eliminating artificial turbulence zones
- Reduction of calculation times by simplifying the fluid domain
For electromagnetic simulations (EM), simplification focuses on:
- Elimination of geometric details without impact on electromagnetic phenomena
- Improvement of precision in areas of high electromagnetic gradient
- Optimization of the ratio between precision and calculation cost
The following table compares simplification requirements according to analysis types:
| Simulation type | Hole criticality | Performance impact | Recommended simplification level |
|---|---|---|---|
| Structural FEA | High | Multiplication of elements up to 300% | Systematic removal of non-functional holes |
| CFD | Medium to high | Flow disturbance, difficult convergence | Selective removal based on flow impact |
| Electromagnetic simulation | Low to medium | Increased calculation times | Targeted simplification in non-critical areas |
| Thermal analysis | Medium | Excessive mesh refinement in thermally non-critical areas | Removal of holes without significant thermal impact |
Traditional methods and their limitations
Faced with the challenges of preparing CAD models for simulation, several traditional approaches are generally used, each presenting significant limitations:
Direct manual approach: The engineer directly modifies the model in its native CAD system, manually removing each hole and detail deemed irrelevant. This method, although precise, presents several major drawbacks:
- Extremely long processing time for complex models
- High risk of human errors and inconsistencies
- Impossibility of efficiently processing models without history
- Non-reproducibility of the process from one operator to another
Complete model reconstruction: This approach consists of entirely recreating a simplified model from the original geometry. While it allows obtaining a result perfectly adapted to simulation needs, it implies:
- A considerable time investment
- Advanced modeling skills
- Possible loss of important geometric information
- A disconnect between the simulation model and the design model
Use of defeaturing tools integrated in pre-processors: Many meshing software packages include basic simplification functionalities, but these tools generally present the following limitations:
- Limited detection capabilities, especially on complex models
- Insufficient topological repair operations
- Lack of control over entity selection criteria
- Difficulties in processing multi-body assemblies
These limitations highlight the need for specialized solutions capable of efficiently processing non-parametric models by automating the detection and removal of holes while preserving the topological integrity of the models.
CADfix DX for automatic hole suppression
Faced with the limitations of traditional methods, CADfix DX positions itself as a specialized solution in CAD geometry transformation for numerical simulation needs. This technology offers CAE analysts advanced functionalities to efficiently prepare models for different types of simulations.
CADfix DX distinguishes itself by its ability to process non-parametric CAD models from various formats and systems, such as CATIA, CREO, NX, SolidWorks, or neutral formats like STEP and IGES, to efficiently prepare them for simulation processes.
Fundamental principles of CADfix DX
The technological approach of CADfix DX is based on several fundamental pillars:
- Software architecture specifically developed for CAD-CAE interoperability
- Geometric engine capable of analyzing and manipulating models regardless of their source
- Advanced algorithms for recognizing geometric features without history
- Topological repair technology ensuring model integrity after modification
The hole suppression tool
The automatic hole suppression module of CADfix DX presents several key functionalities:
- Intelligent detection: Automatic identification of holes based on customizable geometric criteria, even on models without construction history
- Customization options: Possibility to filter holes according to their size, depth, orientation, or position in the model
- Topological reconstruction: Automatic closure of open surfaces after removal, with maintenance of geometric continuity
- Batch processing: Ability to simultaneously process multiple models according to predefined criteria
Complementary functionalities
Beyond hole suppression, CADfix DX offers a set of complementary functionalities essential for simulation model preparation:
- Fillet and chamfer removal: Identification and elimination of fillets and chamfers not relevant for analysis
- Small body processing: Detection and removal or merging of small isolated elements that can disrupt meshing
- Tangency propagation: Semi-automatic selection of connected geometric elements for consistent processing
- Complex area parameterization: Tools allowing adjustment of detail level in critical model areas
These capabilities are particularly valuable for engineering teams facing time and quality constraints in their numerical simulation processes.
Workflow and integration in simulation processes
The efficiency of a CAD preparation solution for simulation is also measured by its ability to integrate harmoniously into existing workflows. CADfix DX offers a structured methodological approach that optimizes the model preparation process.
Recommended methodology
The typical workflow with CADfix DX for automatic hole suppression generally follows these steps:
- Model import: Loading the CAD model from its native or neutral format
- Diagnostic analysis: Automatic identification of potential problems and geometric entities candidates for simplification
- Criteria configuration: Definition of simplification parameters adapted to the targeted simulation type
- Suppression execution: Automatic application of removal operations with preview
- Topological validation: Verification of model integrity after processing
- Export to solver: Generation of the simplified model in the format required by the simulation tool
This structured methodology allows standardization of the preparation process, thus reducing variability and risk of error.
Integration with main solvers
CADfix DX integrates with a wide range of simulation solvers, as demonstrated by its ability to export to different formats:
| Simulation domain | Compatible solvers | Exchange formats |
|---|---|---|
| Finite elements (FEA) | ANSYS, ABAQUS, NASTRAN, LS-DYNA | IGES, STEP, Parasolid, NASTRAN, INP |
| Fluid dynamics (CFD) | FLUENT, CFX, STAR-CCM+, OpenFOAM | STEP, STL, CGNS |
| Electromagnetism | ANSYS Maxwell, COMSOL | STEP, Parasolid |
Workflow automation
For organizations processing a large volume of models or having recurring processes, CADfix DX offers advanced automation capabilities:
- Script creation for automating repetitive tasks
- Batch processing of multiple files according to predefined rules
- Programming interfaces (API) allowing integration into PLM/PDM systems
- Automatic generation of processing reports for traceability
These automation features allow organizations to industrialize their model preparation processes, thus ensuring consistent quality while significantly reducing lead times.
Quantifiable and measurable benefits
The adoption of a specialized solution for automatic hole suppression generates concrete and measurable benefits for organizations. These advantages manifest at several levels and can be quantified to justify the investment.
Reduction in preparation times
One of the most immediate benefits concerns the drastic reduction in model preparation times for simulation:
- 50% to 90% reduction in preparation time for complex models
- Automated processing of hundreds of holes in just a few minutes
- Elimination of repetitive manual tasks with low added value
- Acceleration of product development cycles
This optimization allows engineers to devote more time to analyzing results and improving products rather than preparing models.
Optimization of calculation performance
Targeted model simplification translates into significant improvement in calculation performance:
- Reduction in the number of mesh elements by 30% to 70% depending on the models
- Proportional decrease in calculation times
- Improvement in solver convergence
- Possibility of refining the mesh in critical areas without exceeding hardware capabilities
Mesh quality improvement
Automatic hole suppression directly contributes to improving mesh quality:
- Elimination of very small-sized elements around holes
- Improvement in average aspect ratio of elements
- Reduction of geometric distortions
- Decrease in numerical singularities
These improvements translate into greater accuracy of results and better reliability of analyses.
Impact on development cycles
At the scale of the product development cycle, using a solution like CADfix DX generates strategic advantages:
- 20% to 40% acceleration of simulation cycles
- Increase in the number of design iterations possible in a given time
- Reduction in time-to-market
- Standardization of preparation processes between teams and sites
Industrial application cases
Automatic hole suppression on non-parametric CAD models has demonstrated its value in many industrial sectors. Here are some concrete application cases illustrating the real benefits obtained by organizations that have adopted this approach.
Aerospace industry
In the aerospace sector, where 3D models reach extreme levels of complexity, automatic hole suppression has enabled:
- Preparation of a wing structure model containing more than 5000 holes in less than 30 minutes, compared to 3 days previously
- 80% reduction in file size, facilitating their manipulation and sharing
- Complete automation of the preparation process for recurring vibratory analyses
- Harmonization of working methods between different sites of a large aerospace group
Automotive industry
For an automotive manufacturer, implementing an automatic hole suppression solution led to:
- 65% reduction in preparation time for engine block models for thermal analyses
- Improved accuracy of flow simulations in cooling circuits
- Ability to efficiently process complete assemblies rather than isolated components
- Smooth integration with existing PDM systems via automated workflows
Heavy industry and energy
In the energy sector, an equipment manufacturer found:
- A 70% decrease in time needed to prepare turbine models for structural analyses
- Significant reduction in meshing errors on complex geometries
- Ability to perform analyses of complete assemblies previously impossible to process
- A 35% increase in the number of simulations feasible within the development schedule
Complex multi-body assemblies
For complex multi-body assemblies, particularly present in the manufacturing industry, the adoption of automated hole suppression tools has enabled:
- Processing of assemblies of several hundred components in a single operation
- Preservation of contact interfaces between components despite simplification
- Reduction in the number of mesh elements by 65% without compromising precision at interfaces
- Acceleration of global behavior studies of complex structures
These concrete examples demonstrate the transformative potential of automatic hole suppression in various industrial contexts, with tangible benefits in terms of time, quality, and analysis capability.
Best practices and recommendations
To fully benefit from automatic hole suppression technologies on non-parametric CAD models, several best practices and recommendations can be implemented.
Decision criteria for element removal
Defining relevant criteria constitutes a crucial step for effective simplification:
- For holes: Establish diameter thresholds relative to the overall model size (typically between 1% and 5% of the characteristic dimension)
- For fillets: Define a maximum radius based on the level of detail required for the analysis
- For small bodies: Set a minimum relative volume as a percentage of the total model volume
- For surface details: Evaluate the potential impact on the physical phenomena being studied
These criteria should be documented and standardized within the organization to ensure consistency of results.
Optimization strategies according to simulation type
Adapting the suppression strategy to the targeted simulation type allows optimizing the precision/performance ratio:
| Simulation type | Recommended strategy | Elements to preserve |
|---|---|---|
| Static structural analysis | Aggressive suppression of non-load-bearing holes | Fastening holes, functional bores |
| Vibratory analysis | Moderate suppression with conservation of mass distribution | Large holes influencing inertia |
| Thermal simulation | Conservation of holes on thermal flux paths | Openings for air or fluid circulation |
| CFD | Targeted suppression with preservation of flow characteristics | Elements influencing turbulence |
Quality control and verification
Establishing a robust quality control process is essential to guarantee the validity of simplified models:
- Systematic verification of model watertightness after suppression
- Control of mass properties (volume, center of gravity, inertia) before and after simplification
- Comparison of simulation results on representative subsets before large-scale deployment
- Documentation of modifications made to ensure traceability
Training and skill development
The success of implementing an automatic hole suppression solution also relies on the human factor:
- Thorough training of teams on underlying principles and not just tool usage
- Identification and empowerment of reference users to support deployment
- Development of internal guides adapted to the organization's business specificities
- Implementation of sessions for sharing best practices and feedback
Applying these recommendations allows not only optimizing the use of automatic hole suppression tools but also maximizing their positive impact on engineering processes as a whole.
Conclusion
Automatic hole suppression on non-parametric CAD models now represents a major optimization lever for engineering teams facing the challenges of numerical simulation. This approach allows radical transformation of model preparation processes, with tangible benefits in terms of time, quality, and analysis capability.
Specialized technologies like CADfix DX now offer organizations the means to overcome the inherent limitations of non-parametric models, by automating the detection and suppression of holes while ensuring the topological integrity of models.
The benefits observed in various industrial sectors are eloquent: drastic reduction in preparation times, optimization of calculation performance, improvement in mesh quality, and acceleration of product development cycles. These advantages directly contribute to the competitiveness of organizations by allowing engineers to focus on analysis and innovation rather than model preparation.
As requirements for numerical simulation continue to evolve toward increasingly complex models and more sophisticated analyses, automatic hole suppression tools will become an essential link in the digital chain, contributing to the global optimization of simulation-based engineering processes.
