ACIS
Encyclopedia
The 3D ACIS Modeler is a 3D modelling kernel
(or engine) owned by Spatial Corp
oration (formerly Spatial Technology). ACIS is used by many software developers in industries such as computer-aided design
(CAD), Computer-aided manufacturing
(CAM), Computer-aided engineering
(CAE), Architecture, engineering and construction (AEC), Coordinate-measuring machine
(CMM), 3D animation, and shipbuilding. ACIS provides software developers and manufacturers the underlying 3D modeling functionality.
ACIS features an open, object-oriented C++ architecture that enables robust, 3D modelling capabilities. ACIS is used to construct applications with hybrid modeling features, since it integrates wireframe model, surface
, and solid modeling
functionality with both manifold and non-manifold topology, and a rich set of geometric operations.
There are several versions about what the word ACIS actually stands for, or whether it is an acronym at all. The most popular version is that ACIS stands for Alan, Charles, Ian's System (Alan Grayer, Charles Lang and Ian Braid as part of Three-Space Ltd.), or Alan, Charles, Ian and Spatial (as the system was later on sold to Spatial Technology, now Spatial Corp
). However, when asked, the creators of ACIS would simply suggest that its name was derived from Greek mythology
(See also Acis
).
In 1985 Charles Lang and Ian Braid (creators of Romulus
and Romulus-D) formed Three-Space Ltd. (Cambridge
, England
) which had been retained by Dick Sowar's Spatial Technology (which had ben founded by Sowar in 1986) to develop the ACIS solid modeling kernel for Spatial Technology's Strata CAM software. The first version of ACIS was released in 1989 and was quickly licensed by HP
for integration into its ME CAD software.
In late 2000, around the time when Spatial was acquired out by Dassault Systemes
, the ACIS file format changed slightly and was no longer openly published.
The ACIS product line is designed using software component technology, which allows an application to use only the components it requires. In some cases, more than one component is available (either from Spatial or third party vendors) for a given purpose, so application developers can use the component that best meets their needs. For example, several rendering components are available from Spatial, and developers use the one that works best for their platform or application.
and NURBS curves and surfaces.
Advanced Covering: Advanced Covering is a feature of Deformable Modeling that is now available as a standalone add-on for the 3D ACIS Modeler. This single API uses sophisticated algorithms to create high-quality n-sided surfaces that meet user-specified tolerances for position and continuity on boundaries and on optional internal guiding geometry. Advanced Covering allows a surface to be fit onto circuits (collections of edges that form closed loops) in solid or wire bodies, which is useful in consumer product design. Among other uses, Advanced Covering can be used for end-capping, post-translation corrections, and surface definition from curve data.
Defeaturing: Defeaturing automatically identifies and removes small features that CAE analysts typically want to eliminate from the 3D model prior to meshing. Analysts frequently work from the same models that are used for design and manufacture, but these models often carry much more detail than is necessary for simulation
or analysis purposes. By removing unnecessary detail, Defeaturing simplifies the model, a process that typically is done manually at significant cost.
3D PHL V5: 3D ACIS PHL V5 is a hidden line removal (HLR) solution from Spatial based on CATIA
V5 technology. 3D ACIS PHL V5 is an ACIS-dependent development technology - an ACIS license is required. Though 3D is now the de facto CAD standard in most engineering disciplines, 2D still has a place in industries such as technical illustration, manufacturing
, and architecture
. Since 3D models are the typical primary output for CAD design, users in these industries require an efficient and accurate method of generating 2D computational drawings directly from the 3D models. Hidden line removal (HLR) is an important aspect of creating an accurate 2D representation from a 3D model. Using HLR, the converted model only displays those parts visible from a given perspective; hidden (or occluded) edges normally included in a 3D model representation are removed, or drawn in a line style that indicates their obscured position.
Beginning with ACIS Release 6.3, it is required that the product ID and units be populated for the file header before you can save a SAT file.
Beginning with ACIS Release 4.0, the SAT save file format does not change with minor releases, only with major releases. This allows applications that are based upon the same major version of ACIS to exchange data without being concerned about the save version. To provide this interoperability in a simple implementation, ACIS save files have contained a symbol that accurately identified the major version number, but not the minor version. This meant that applications created using the same major version of ACIS would produce compatible save files, regardless of their minor versions. This was accomplished by simply not incrementing the internal minor version number between major versions.
Beginning with Release 7.0, ACIS started again providing accurate major, minor, and point version numbers.
To summarize how release numbers and SAT changes are related:
Kernel (computing)
In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources...
(or engine) owned by Spatial Corp
Spatial Corp
Spatial Corporation was founded in 1986, and had one main product: ACIS, the first commercially available 3D modeling kernel. Through subsequent years, Spatial added products to its portfolio that enabled ISVs mostly in the CAD/CAM industries, to build applications...
oration (formerly Spatial Technology). ACIS is used by many software developers in industries such as computer-aided design
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...
(CAD), Computer-aided manufacturing
Computer-aided manufacturing
Computer-aided manufacturing is the use of computer software to control machine tools and related machinery in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a...
(CAM), Computer-aided engineering
Computer-aided engineering
Computer-aided engineering is the broad usage of computer software to aid in engineering tasks. It includes computer-aided design , computer-aided analysis , computer-integrated manufacturing , computer-aided manufacturing , material requirements planning , and computer-aided planning .- Overview...
(CAE), Architecture, engineering and construction (AEC), Coordinate-measuring machine
Coordinate-measuring machine
A coordinate measuring machine is a device for measuring the physical geometrical characteristics of an object. This machine may be manually controlled by an operator or it may be computer controlled. Measurements are defined by a probe attached to the third moving axis of this machine...
(CMM), 3D animation, and shipbuilding. ACIS provides software developers and manufacturers the underlying 3D modeling functionality.
ACIS features an open, object-oriented C++ architecture that enables robust, 3D modelling capabilities. ACIS is used to construct applications with hybrid modeling features, since it integrates wireframe model, surface
Surface
In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...
, and solid modeling
Solid modeling
Solid modeling is a consistent set of principles for mathematical and computer modeling of three dimensional solids. Solid modeling is distinguished from related areas of Geometric modeling and Computer graphics by its emphasis on physical fidelity...
functionality with both manifold and non-manifold topology, and a rich set of geometric operations.
History
As a geometric kernel, ACIS is a second generation system, coming after the first generation RomulusRomulus (b-rep solid modeler)
The Romulus b-rep solid modeler was released in 1982 by Ian Braid, Charles Lang and the Shape Data team in Cambridge, England. It was the first commercial solid modeling kernel designed for straightforward integration into CAD software...
There are several versions about what the word ACIS actually stands for, or whether it is an acronym at all. The most popular version is that ACIS stands for Alan, Charles, Ian's System (Alan Grayer, Charles Lang and Ian Braid as part of Three-Space Ltd.), or Alan, Charles, Ian and Spatial (as the system was later on sold to Spatial Technology, now Spatial Corp
Spatial Corp
Spatial Corporation was founded in 1986, and had one main product: ACIS, the first commercially available 3D modeling kernel. Through subsequent years, Spatial added products to its portfolio that enabled ISVs mostly in the CAD/CAM industries, to build applications...
). However, when asked, the creators of ACIS would simply suggest that its name was derived from Greek mythology
Greek mythology
Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...
(See also Acis
ACIS
The 3D ACIS Modeler is a 3D modelling kernel owned by Spatial Corporation . ACIS is used by many software developers in industries such as computer-aided design , Computer-aided manufacturing , Computer-aided engineering , Architecture, engineering and construction , Coordinate-measuring machine...
).
In 1985 Charles Lang and Ian Braid (creators of Romulus
Romulus (b-rep solid modeler)
The Romulus b-rep solid modeler was released in 1982 by Ian Braid, Charles Lang and the Shape Data team in Cambridge, England. It was the first commercial solid modeling kernel designed for straightforward integration into CAD software...
and Romulus-D) formed Three-Space Ltd. (Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
) which had been retained by Dick Sowar's Spatial Technology (which had ben founded by Sowar in 1986) to develop the ACIS solid modeling kernel for Spatial Technology's Strata CAM software. The first version of ACIS was released in 1989 and was quickly licensed by HP
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
for integration into its ME CAD software.
In late 2000, around the time when Spatial was acquired out by Dassault Systemes
Dassault Systemes
Dassault Systèmes S.A. is a leading company specializing in 3D and PLM software.Dassault Systèmes develops and markets PLM application software and services that support industrial processes and provide a 3D vision of the entire lifecycle of products from conception to maintenance to recycling...
, the ACIS file format changed slightly and was no longer openly published.
Architecture
A software component is a functionally specialized unit of software—a collection of software items (functions, classes, etc.) grouped together to serve some distinct purpose. It serves as a constituent part of a whole software system or product. A product is one or more software components that are assembled together and sold as a package. Components can be arranged in different combinations to form different products.The ACIS product line is designed using software component technology, which allows an application to use only the components it requires. In some cases, more than one component is available (either from Spatial or third party vendors) for a given purpose, so application developers can use the component that best meets their needs. For example, several rendering components are available from Spatial, and developers use the one that works best for their platform or application.
Supported Platforms and Operating Systems
| Platform | Operating System | Compiler | 32-bit | 64-bit |
|---|---|---|---|---|
| Microsoft | Windows XP Professional SP2 | Visual C++ .NET 2005 | X | X |
| Microsoft | Windows 2000 SP4 | Visual C++ .NET 2003 | X | |
| Microsoft | Windows XP Professional x64 Edition | Platform SDK for Windows Server February 2003 Version 13.10.2240.8 | X | |
| Red Hat | Enterprise Linux, Version 5 | GNU C++ gcc 4.1.2 | X | X |
| Apple | OS X 10.4 (Native BSD) | GNU C++ gcc 4.0 and XCode 2.3 | X | |
| IBM | AIX Version 5.3 | VisualAge C++ Version 8.0 | X | X |
| HP | HP-UX 11i v1 | HP aC++ Version A.03.52 | X | X |
| SunTM | SolarisTM 10 | Sun ONETM Studio 10 | X | X |
3D Modelling
- Extrude/revolve/sweep sets of 2D curves into complex surfaces or solids.
- Fillet and chamfer between faces and along edges in surface and solid models.
- Fit surfaces to a closed network of curves.
- Generate patterns of repetitive shapes.
- Hollow solids and thicken surfaces.
- Interactively bend, twist, stretch, and warp combinations of curves, surfaces, and solids.
- Intersect/subtract/unite any combination of curves, surfaces, and solids.
- Loft surfaces to fit a set of profile curves.
- Taper/offset/move surfaces in a model.
3D Model Management
- Attach user-defined data to any level of a model.
- Track geometry and topology changes.
- Calculate mass and volume.
- Model sub-regions of a solid using cellular topology.
- Unlimited undo/redo with independent history streams.
3D Model Visualization
- Tessellate surface geometry into polygonal mesh representation.
- Create advanced surfacing capabilities with the optional Deformable Modeling component.
- Generate precise 2D projections with hidden line removal using optional PHL V5 component.
- Develop graphical applications
ACIS Modeler Extensions
3D Deformable Modeling: 3D Deformable Modeling is an interactive sculpting tool for shaping 3D models. Included as part of Spatial's suite of 3D modeling development technologies, 3D Deformable Modeling uses local and global editing features that allow for the easy creation and manipulation of free-form B-splineB-spline
In the mathematical subfield of numerical analysis, a B-spline is a spline function that has minimal support with respect to a given degree, smoothness, and domain partition. B-splines were investigated as early as the nineteenth century by Nikolai Lobachevsky...
and NURBS curves and surfaces.
Advanced Covering: Advanced Covering is a feature of Deformable Modeling that is now available as a standalone add-on for the 3D ACIS Modeler. This single API uses sophisticated algorithms to create high-quality n-sided surfaces that meet user-specified tolerances for position and continuity on boundaries and on optional internal guiding geometry. Advanced Covering allows a surface to be fit onto circuits (collections of edges that form closed loops) in solid or wire bodies, which is useful in consumer product design. Among other uses, Advanced Covering can be used for end-capping, post-translation corrections, and surface definition from curve data.
Defeaturing: Defeaturing automatically identifies and removes small features that CAE analysts typically want to eliminate from the 3D model prior to meshing. Analysts frequently work from the same models that are used for design and manufacture, but these models often carry much more detail than is necessary for simulation
Simulation
Simulation is the imitation of some real thing available, state of affairs, or process. The act of simulating something generally entails representing certain key characteristics or behaviours of a selected physical or abstract system....
or analysis purposes. By removing unnecessary detail, Defeaturing simplifies the model, a process that typically is done manually at significant cost.
3D PHL V5: 3D ACIS PHL V5 is a hidden line removal (HLR) solution from Spatial based on CATIA
CATIA
CATIA is a multi-platform CAD/CAM/CAE commercial software suite developed by the French company Dassault Systemes...
V5 technology. 3D ACIS PHL V5 is an ACIS-dependent development technology - an ACIS license is required. Though 3D is now the de facto CAD standard in most engineering disciplines, 2D still has a place in industries such as technical illustration, manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
, and architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...
. Since 3D models are the typical primary output for CAD design, users in these industries require an efficient and accurate method of generating 2D computational drawings directly from the 3D models. Hidden line removal (HLR) is an important aspect of creating an accurate 2D representation from a 3D model. Using HLR, the converted model only displays those parts visible from a given perspective; hidden (or occluded) edges normally included in a 3D model representation are removed, or drawn in a line style that indicates their obscured position.
File format
ACIS saves modeling information to external files which have an open format allowing external applications, even those not based on ACIS, access to the ACIS geometric model. The basic information needed to understand the ACIS file format (focusing on the reading, or restore, operation), includes the structure of the save file format, how data is encapsulated, the types of data written, and subtypes and references.Save File Types
ACIS supports two kinds of save files, Standard ACIS Text (SAT), and Standard ACIS Binary (SAB). The two formats store identical information, so the term SAT file is generally used to refer to either (when no distinction is needed). SAT files are ASCII text files that may be viewed with a simple text editor. A SAT file contains carriage returns, white space and other formatting that makes it readable to the human eye. A SAT file has a .sat file extension. SAB files cannot be viewed with a simple text editor and are meant for compactness and not for human readability. A SAB file has a .sab file extension. A SAB file uses delimiters between elements and binary tags, without additional formatting.Structure of the Save File
A save file contains:- a three-line header
- entity records, representing the bulk of the data
- optionally, a begin history data marker
- optionally, old entity records needed for history and rollback
- optionally, an end history data marker
- an end marker
Beginning with ACIS Release 6.3, it is required that the product ID and units be populated for the file header before you can save a SAT file.
Version Numbers and ACIS Releases
ACIS is currently being developed by Spatial. They maintain the concept of a current version (release) number in ACIS, as well as a save version number. The save version allows one to create a SAT save file that can be read by a previous version of ACIS.Beginning with ACIS Release 4.0, the SAT save file format does not change with minor releases, only with major releases. This allows applications that are based upon the same major version of ACIS to exchange data without being concerned about the save version. To provide this interoperability in a simple implementation, ACIS save files have contained a symbol that accurately identified the major version number, but not the minor version. This meant that applications created using the same major version of ACIS would produce compatible save files, regardless of their minor versions. This was accomplished by simply not incrementing the internal minor version number between major versions.
Beginning with Release 7.0, ACIS started again providing accurate major, minor, and point version numbers.
To summarize how release numbers and SAT changes are related:
- Major release: SAT file changes may be made; significant functionality changes likely; may require significant changes to existing applications
- Minor release: No SAT file changes are made; may provide new functionality; may require some minimal changes to existing applications
- Point release: Minor changes only (bug fixes). (Also known as service packs).
| Release | Date |
|---|---|
| 21.0 | May 2010 |
| 20.0 | May 2009 |
| 19.0 | July 2008 |
| 18.0 | November 2007 |
| 17.0 | April 2007 |
| 16.0 | January 2006 |
See also
- Comparison of CAD editors for Architecture, Engineering and Construction