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- This directory contains version 6.0 of the IRIT 3-D solid modeler.
- The binaries require at least a 68020, and an FPU. The main IRIT
- binary requires 18M or virtual (or real, if you are *that* lucky)
- memory to run.
-
- General Information:
-
- IRIT is a solid modeling environment that allows one to model basic,
- primitive based, models using Boolean operations as well as freeform
- surface's based models.
-
- The system is designed for simplicity and is geared toward research.
- As such, no graphical user interface (GUI) exists or is planned in the
- near future. The modeling is performed using the main
- module/executable of the system which is called (surprise!) IRIT. A
- textual interface (or PUI for programmable user interface) is
- available which provides the interaction interface. An interpreter
- processes the user's command and executes them. This interpreter
- includes general mechanisms that are common in high level programming
- languages such as loops, conditional sentences, and functions. In
- addition, features that can be found in modern languages such as
- operator overloading and object oriented design are extensively used.
-
- Version 6.0 of the IRIT solid modeling system contains tools that can
- aid in research and development in the areas of computer aided
- geometric design and computer graphics. Here is a list of the features
- that can be found:
-
- * Full featured points/vectors/homogeneous matrices algebra by overloading
- the basic operators +,-,*,/,^.
-
- * Polygonal based modeling. Constructors for basic primitives (box, cone,
- torus, etc.) are provided as well as low level constructors for direct
- polygonal model's construction. Boolean operations between polygonal
- models is also supported.
-
- * Freeform curve and surface manipulation tools. Supported are
- polynomial and rational Bezier and piecewise polynomial/rational NURB
- curves and surfaces. A large set of tools to manipulate freeform curves
- and surfaces is provided and includes (for both curves and surfaces):
-
- o Low level Constructors (direct control points control).
- o High Level Constructors (Sweep, Extrude, Boolean Sum, etc.).
- o Merging and Profiling tools.
- o Evaluation.
- o Subdivision.
- o Refinement.
- o Degree Raising.
- o Differentiation and Integration.
- o Symbolic Computation (Difference, Sum, and Product).
- o Polygonal/Polyline approximation.
- o Composition.
- o Offset.
- o Trimmed surfaces.
-
- * Tools to compute the zero set of curves, the extreme points,
- the minimal or maximal distance from a curve to a point or a line,
- the inflection points and/or points of extreme curvature, and the
- intersection points of two curves are also available.
-
- The symbolic tools provided allow one to represent scalar and
- vector fields of differential properties of the curves and surfaces
- such as normals and curvature. The curve's inflection and extreme
- curvature detection tools, mentioned above, exploits these symbolic
- tool and are therefore robust.
-
- * Trivariate Bspline and bezier support that includes evaluation, iso surface
- extraction, subdivision, differentiation etc.
-
- * In addition to the main module of IRIT, several other tools are provided:
- o poly3d-h: A hidden line removal tool.
- o illustrt: A line drawing illustration tool.
- o xgldrvs/xglmdrvs/xmtdrvs/x11drvs/wntdrvs/os2drvs/amidrvs: Display
- devices (and viewing programs at the same time) for SGI's gl, gl/Motif,
- X11, X11/Motif, Window NT, OS2 2.x, and AMIGA. All these drivers
- support the display of animation using animation curves.
- o irit2ps/irit2dxf/irit2iv/irit2nff/irit2plg/irit2ray/irit2scn/irit2xfg:
- Filters to convert data files created by IRIT to PostScript, DXF,
- SGI Inventor, NFF, REND386, Rayshade, SCN, and Xfig format.<TR>
- o dat2irit/dxf2irit: Filters to convert from data file of IRIT to IRIT's
- solid modeling scripts and from DXF to IRIT.<TR>
-
- * The IRIT solid modeller is actively used in various research
- areas. Several examples include:
-
- o Adaptive Isocurve Algorithm. A coverage based on adaptive extraction
- of isocurves can be used for various purposes from toolpath for
- machining purposes to image rendering. This algorithm, that is
- exploiting symbolic computation, is implemented using the IRIT
- solid modeller and a tool named xgladap make use of the hardware of
- the SGI systems to provide real time rendering using adaptive
- isocurves.
- o Layout. A new fabrication scheme automatically computes an
- approximated layout of a free form surface, on the plane, so it
- can be cut from planar sheets (such as paper or fabric) and
- stitched together to form an approximation of the original
- surface. Tools to automatically compute the layout were implemented
- using IRIT.
- o Morphing. Using refinement and degree raising, two tools that are
- available in this system, different surfaces can be brought to
- a common function space and be continuously morphed or transformed
- from one to the other. Again, a successful implementation exists in
- IRIT.
- o Matching. The inter-correspondance between two freeform curves is
- of importance in various applications from modeling (ruled and blend
- surfaces), through graphics (morphing), to computation geometry
- (offset computation).
- o Illustrt. Line drawings is a neglected area of computer graphics.
- Illustrt is a tool developed with the aid of IRIT, and now is part
- of IRIT, to automatically generate line drawings with special effects
- such as width/size and intensity depth cueing, Z sorting, and end of
- edge clipping etc.
-
- * The system is written in C and is running on virtually all Unix
- environments, including but not limited to SUN's SPARC, SGI's SGI4D,
- HP3xx/4xx/7xx, DEC 5000, IBM RS6000, E&S ESV, and i386 SVR4, using
- either X11 or, when available, SGI's GL. In addition, other
- environments such as Window NT and OS2 using IBM PC 386 and above or
- 68xxx AMIGA are also supported.
-