Interactive Mesh Features (IMF) is an intuitive CAD modeling software for manipulating large-volume CAE meshes. IMF can add geometric features to a mesh surface or morph entire regions of a mesh model and capture each as a feature in a history tree. The individual features can be saved as templates to be applied to other models or later recalled to automatically generate a family of mesh models according to a DOE orthogonal table. IMF was developed with ease-of-use in mind and offers CAE engineers a nimble alternative to the existing CAD/CAE software.

 

Images & Features




IMF’s Direct Surface Manipulation can deform a user-specified region on an existing mesh while maintaining the desired continuity between a deformed and the un-deformed region. The user can define the maximum deformation and intuitively control the transition from the maximum deformation to the boundary of the region using a basis function:

where is the new position of a point V within a DSM, D the maximum displacement of DSM, t the parameter of V and f the basis function.

	Using the basis function to control a DSM feature

	Multiple peaks within a deformed region are possible with a DSM feature.		A line-type DSM used to create a spoiler shape on a vehicle mesh model

 

IMF’s lattice morphing (based on the Free-Form Deformation), allows modification of an object embedded inside a volume described by a three-dimensional grid called the lattice. After parameterizing the object within the domain of the lattice, the change of the object is controlled by the change of lattice grid vertices:

where V is a parameterized point and {Pi,j,k} are the vertices; and {Bi}, {Bj}, {Bk} are the basis functions in three parameter directions, respectively.

	A lattice grid used to change the windshield angle of a vehicle aerodynamic CAE model. A row of grid vertices (marked in red) is to be displaced by a user.

Inverse Morphing allows a user to directly edit mesh nodes. The system performs the task of repositioning the corresponding grid vertices automatically.

where V is a parameterized point and {Pi,j,k} are the vertices; and {Bi}, {Bj}, {Bk} are the basis functions in three parameter directions, respectively.

	Three mesh nodes are moved to their target locations (green lines indicate displacements). The UI form allows precise specification of target positions. The same lattice is used but is not shown.

DSM and lattice morphing can be represented as mesh features that contain mathematical operations to achieve a particular deformation. Mesh features are context-free, stored separately from a base mesh, and can be applied to the mesh in a desired mix at any time. Libraries of feature can also be created.

DoE Builder - IMF has a mesh feature replay mechanism that allows one to quickly shape a base mesh model into a desired shape. To maximize the power of replay, a macro was developed for the replay to execute repeatedly, each time using a unique set of mesh features as specified by the DoE study. IMF’s DoE interface allows the user to assign mesh features to DoE factors, specify output file names, and change and verify replay order

Benefits Summary

Workflow improvement:

• Direct Mesh Modification allows a CAE engineer to work with a mesh directly without going down the traditional "change-through-CAD" route.
• IMF's unique Direct Surface Manipulation, or DSM, tool allows the user the simultaneous manipulation of multiple mesh nodes within a user specified region on a mesh. The user has direct control over the shape of the region, the maximum deformation within the region. A basis function provides an intuitive way to control the continuity and shape characteristics of the deformation.
• IMF's lattice morphing tools allow the user to deform a mesh using a three-dimension grid. The user can either interactively morph the mesh by directly repositioning grid vertices or directly morph the mesh and have the system determine how to reposition the grid vertices.

Context-free Mesh Feature:

• IMF implemented both DSM and Lattice Morphing as self-contained shape features that are context-free, stored separately from a base FEA model, and can be applied to the model in a proper mix at any time. This allows the user to:

  
  - Save a mesh deformation for future use
  - Save a mesh deformation as a template for use on other vehicle designs
  - Create a mesh template library for the maximum efficiency of reusing existing work.
  
  

• Provides immediate knowledge of product performance in the hands of the By assigning mesh features for DoE factors, one can specify for the system the proper way to assemble them and apply automatically to the base model to generate a family meshes for a DoE study. Automatic generation DoE meshes results in maximum time savings and minimum chances for errors, especially for applications involving large-scale CAE models.

Applications

Pre-processing of CAE data:

• Vehicle exterior airflow CAE analysis
• Vehicle exterior airflow CAE analysis
• Certain structural CAE analysis applications
• CAE based Design of Experiment studies

Development Status

The latest version, IMF2.3, includes all the major functionalities, i.e., the Direct Surface Manipulation functionality, the lattice morphing functionality, mesh feature capability, and the DoE Builder interface. It runs on either a PC-based or an NT based platform. IMF2.4, which is under development, includes several new functionalities, such as mapping a mesh surface to given reference curves.

Licensee Support

• Technical reports
• IMF executables
• Source codes
• Consulting