ACIS Release Notes/R21
Package and Build Changes
HP-UX and Solaris
- HP-UX and Solaris platforms have been discontinued. ACIS and InterOp binaries are no longer provided for Hewlett-Packard HP-UX and for SUN Solaris operating systems. For currently supported platforms, refer to the platform support documentation for either ACIS or InterOp.
- CATIA V5 Reader and Writer are currently not supported on the Windows 7 x64 environment. All other InterOp Readers and Writers are supported on the Windows 7 operating system. The configuration has been tested on Windows 7 with no resulting critical problems.
- InterOp binaries are supported on the AIX 6.1 (TL02) operating system. The configuration has been tested on AIX 6.1 with no resulting critical problems.
api_slice now has an optional failsafe mode. In this mode, a partial intersection graph may be returned in the event of problems. Pairs of faces which experienced problems are returned using the error_info structure.
To enable this functionality, switch the global option fss on, as well as enabling general failsafe behavior.
Projection with a Tolerance
A 3-space tolerance can now be set in the project_options object, to be used in projection operations, such as api_project_wire_to_body. This can be used to "snap" projected edges or vertices to pre-existing edges or vertices in the target body, if they are within tolerance. The resulting body containing the imprinted projected wire may contain additional tolerant vertices.
Detection of sliver faces through api_detect_sliver_faces has been made more robust in this release. This behavior change helps detect appropriate sliver faces that may have been overlooked in an earlier version of ACIS.
Direct Option Support to the Meshing of Non-Manifold Geometries and Internal Surfaces
- Main article: EDA_Mesh_Options#Parameters That Can Be Set Directly
This enhancement to the bridge provides direct support of the setting of two more options in VKI. These options are particularly critical when generating surface meshes.
|Option||Type of Mesh||Default||Description|
|Enable Support of Non-Manifolds|| || ||
Logical value to enable support of the surface meshing of non-manifold geometries, in which more than two input triangles share a common edge. By default, however, for historical reasons, the module in VKI assumes that non-manifold geometry is a modeling error and attempts to remove non-manifold input triangles from the geometry. This bridge reverses this option by switching on this support.
|Internal Surface Meshing (double-backed)|| || ||
Logical value to facilitate generating triangulations on the boundaries of solids which are to be subsequently tetrahedralized by the TetMesh module. In this case all internal triangles are replicated by a coincident triangle with opposite sense, that is, the internal triangles are "double backed". This is the convention used by the TetMesh module for flagging boundary triangles which are internal.
The Faceter has been vigorously improved for R21.
- The spline gridding algorithm has been rewritten to greatly improve accuracy and robustness.
- The default tolerances have been revised for reduced facet count.
- If you use refinements, we advise that you reevaluate their tolerance choices to achieve optimum performance.
- The algorithm has been refactored to reduce memory footprint per facet.
- The interface has been simplified.
- For pre-R21 behavior, call the faceting APIs with the version tag set below R21.
Testing on a large random sample of parts indicates the default visualization settings generate half as many facets as the default settings in R20.
Much Smaller Memory Footprint
The amount of memory used during the faceting operation is much smaller for bodies with a large number of faces (except when using the LINKED_MESH_MANAGER).
New Default Settings
Also, the default for normal tolerance in REFINEMENTS has been changed from 15 to 30 degrees.
Faceter Problem Reporting
In R21 the Faceter returns detailed error information with the outcome object returned by the APIs. Refer to Faceter Problem Reporting for details.
Changes Needed to Your Mesh Manager
If you wrote your own mesh manager, it may need improvements to be used with the R21 Faceter. Refer to Updating Your Mesh Manager for details.
The Faceter has been tuned for visualization and analysis workflows using facet_options objects. The new Faceter uses more computational effort to ensure uniform quality which allows significantly lower facet count and lower memory usage with predictable results. Users may observe longer faceting times using R21 default settings compared to R20 default settings, but the R21 results more reliably represent all features in a more efficient mesh.
Recommended Mesh Manager
ACIS has introduced functionality to manipulate and visualize large sets of points in this release. This functionality is implemented by a rich C++ interface, including the SPApoint_cloud class. Also, several new Scheme extensions have been made available for exploring this functionality. For more information, refer to Point Cloud.
The sheet thicken algorithm (api_sheet_thicken) has been vastly enhanced to improve its robustness and performance. Due to this change, you may encounter topology-related behavior changes such as vent faces being created to prevent large tolerant edges or vertices.
New "unsigned" Distance Mode Added to api_entity_point_distance
The api_entity_point_distance API now has an option to provide unsigned distances. This is provided via SPAentity_point_distance_options. Previously, ACIS solely had signed distances or the default (distance to solid). ACIS now has three distance modes with the following properties:
- Distance to solid (default) mode for returning zero for any internal or boundary points, and a positive distance for external points
- Signed distance mode for returning negative distances for internal points, zero for boundary points, and positive distances for external points
- Unsigned distance mode for returning the same as the signed distance mode except that it is always non-negative.
Initialization and Termination
New Product-specific Features
History Callbacks Have Been Moved
The history callbacks that help keep HOOPS segments up-to-date during roll operations have been moved from the HOOPS/ACIS Bridge to the HOOPS/ACIS Part Management component (HA_Part). These callbacks as implemented require part management knowledge, which is not available at the bridge level. As a consequence, entities not belonging to the active part were erroneously rendered to the display. Customers utilizing the bridge without ACIS Part Management will have to implement history callbacks that keep HOOPS segments up-to-date during roll operations in conjunction with their custom part management implementations. Refer to Entity Callbacks and History Callbacks for more details.