The 3D ACIS Modeler (ACIS) is an object-oriented three-dimensional (3D) geometric/solid modeling engine from Spatial Corp. It is designed for use as the geometry foundation within virtually any end-user 3D modeling application. Written in C++, ACIS provides an open architecture framework for wireframe, surface, and solid modeling from a common, unified data structure.
The ACIS System represents the core functionality upon which the modeling system is based. Essentially, the core functionality manages models such as creating, copying, deleting, as well as saving and restoring models to disk. This framework also discusses ACIS' history mechanism for implementing undo/redo for your models, and best practices for optimizing your applications that use ACIS.
The ACIS Blending Framework comprises two components (Blending and Advanced Blending) which facilitate the creation of smooth blend surfaces and chamfers in order to replace sharp edges and vertices in a model. The ACIS Blending Frameworks allow creation of rolling ball, variable radius, entity-entity, three entity, curvature continuous, and holdline blends. The surfaces in this framework are generally ACIS procedural surfaces except when analytic representations are possible.
The ACIS Local Operations Framework comprises five components which facilitate the modification of ACIS bodies. The term Local Operations implies a change to modeling geometry in a localized fashion; specifically the modification of a surface definition under a topological face. This concept has been expanded to encompass body offset, shelling, move, tapering and sheet extend. In this context, a great deal of topological changes are possible and handled by their respective operators. In addition, this framework includes the components for face and wire edge removal, as well as repairing body self-intersections.
The Local Operations Component (LOP) is the base component of the framework. The core algorithm, TWEAK, replaces the surface definition of a face and is the main work horse for all the operations in this framework. TWEAK can be called standalone via api_tweak_faces. In addition, this component includes body offsetting, move, tapering, and sheet extend functionality...
The Remove Component (REM), supports the removal of faces from bodies and heals the resulting body with the remaining faces. In addition, the component supports the removal of edges from a wire body and healing the gap by edge extension ...
The Repair Body Intersections Component (RBI), repairs body self-intersections that arise from performing a modeling operation. RBI is used by Local Operations, Shelling, and other components like Sweeping and Blending ...
The ACIS Modeling Visualization and Display framework comprises four components which facilitate the display list, faceting, and hidden line removal of an ACIS model. The flagship component of this ACIS Framework is the HOOPS/ACIS Bridge which supports the generation of HOOPS® display data from an ACIS model. In conjunction with the HOOPS/ACIS Bridge is the ACIS Faceter and two forms of hidden line removal (interactive and precise).
The HOOPS/ACIS Bridge encapsulates the work needed to connect ACIS modeler from Spatial to the HOOPS/3dGS. The bridge provides an API for controlling the manner in which ACIS' geometric tessellation is mapped to HOOPS primitives ...
The Faceter Component (FCT) generates and controls approximate polygonal representations. The polygon approximations are used in all active and static rendering, in clearance analysis, and in operations where approximations are acceptable to simplify calculations ...
The Modeling Operations framework is a collection of related components that make up the foundation of the modeler. Some of the key components are Constructors (solid generation), Booleans Operations (solid manipulation), and Stitching (solid repair). Additionally, it implements support functionality, such as the uppercase classes used in topology, as well the upper- and lowercase geometryclasses.
The ACIS Surfacing framework comprises components which facilitate the construction of surfaces and topology built primarily from 3D curves. In all cases, the construction techniques build the required surfaces and topology for a proper closed or open solid body. The surfaces in this framework are generally ACIS procedural surfaces except when analytic representations are possible.
This component (SKIN) provides techniques for creating surfaces and faces by interpolating a sequence of edges, coedges, or wires, arbitrarily positioned in model space. It is subdivided into:
Skinning — A modeling technique that fits a surface through a series of disjoint curves (wire bodies), creating a sheet body or a solid body.
Lofting — A modeling technique that starts with a surface and fits another surface through a coedge of the original surface and a series of curves (coedges).
Net Surfaces — A surfacing technique that uses a network of curves defining both the u and v surface parameter directions (often called "bi-directional" curves because of this), unlike skinning and lofting which only take curves defining the u parameter.
This component (COVR) is used to fit a surface over the boundary defined with a closed and connected circuit of curves. It generates a sheet or solid body from a set of closed wires or closed circuits in sheet or solid bodies.
This component (ADM) is used to create or manipulate freeform curves and surfaces. Advanced Covering is a high-level interface to ADM that is used to cover (that is, fit a surface onto) closed circuits in solid, sheet, or wire bodies.