LEDAS Releases LGS 2D v5 Constraint Solver with Extended Functions

New constraints include circular and variable patterns, and directed distances with ellipses, helping users of CAD/CAM/CAE applications to fully control their constrained drawings

Using circular pattern constraint for bearing design with LGS 2D 5.0

LEDAS Ltd today announced version 5.0 of LGS 2D, its geometric constraint solver. As the core technology of parametric software, LGS 2D allows users to express design intent in their sketches and drawings through geometric and dimensional constraints.

Version 5.0 extends the functionality of pattern constraints that were introduced in the previous version of LGS 2D. New are circular and variable patterns, as well as distance constraints for ellipses.

New Features in LGS 2D 5.0

LGS 2D v5 introduces variable patterns, both linear and circular:

  • Linear variable patterns extend ordinary linear patterns introduced in the previous version of LGS 2D. They link the distance between centers of any two adjacent objects with variables, allowing non-uniform distribution along a given direction, fully controlled through variables. The lengths of all the intervals not linked to variables are made uniform by the solver.
  • Circular patterns are applied to sets of objects of the same type. Another argument is the point, around which LGS 2D distributes the objects. The distance between the point and each object is equal, as are the angles between adjacent rays (that connect the point with objects’ centers).
  • Circular variable patterns, similarly to linear variable patter, use variables to control the angles between adjacent rays.
The directed distance constraint was firstly implemented in LGS 2D; in v5, ellipses can be used as arguments to this kind of constraint. Now any object (except lines, for which directed distances do not make sense) can be constrained with this type of constraint.

Version 5.0 finalizes the new family of functions introduced with the previous version, following requests from our customers,” explained Dmitry Ushakov, Director of Product Management at LEDAS. “We are now focusing on the next significant step in LGS 2D development, which we plan to announce at the beginning of 2011.

About LGS Software

Since the first commercial release in 2004, LGS 2D/3D software components have been licensed by a dozen CAD/CAM/CAE vendors, who have embedded them into their applications successfully.

The LGS 2D and 3D geometric constraint solvers are used as parametric engines for 2D sketching and drawing, history-free 3D modeling, assembly design, motion analysis, and other applications. LGS 2D/3D are cross-platform software packages running on 32- and 64-bit versions of Windows, Linux, Mac OS X, *BSD, AIX, HP-UX, and other operating systems. LGS 2D and 3D have a C-style API for easy integration into a broad range of software applications using a variety of wrappers, such as .NET, Java, and C++.

LGS 2D/3D supports the creation and modification of geometric models by means of explicit and implicit constraints. Geometric objects that can be constrained include points, lines, circles, ellipses, planes, cylinders, spheres, NURBS, application-defined parametric curves, and surfaces. Objects can be fixed in the absolute coordinate system or relative to each other. Supported constraints include geometric relations between objects (coincidence, parallelism, tangency, and so on) and dimensions that specify the required values for distances, angles, and radii. LGS 2D/3D moves and rotates objects to positions that satisfy all constraints, yet minimizes transformations from initial configurations.

Other LGS functions implement advanced features of CAD/CAM/CAE systems, such as diagnostics of over- and under-defined parts of models, engineering variables and equations, help points, and tolerance management.

“Lege’n’d 2D/3D” are example applications that are available as free downloads from the LEDAS web site. They include a collection of sample models representing different kinds of 2D sketches and 3D assemblies, and the applications can be used to test the functionality, robustness, and performance of LGS 2D/3D. The sample applications were created with the Open CASCADE open-source application framework; the source code is available to all licensees.

All members of Open Design Alliance can easily integrate LGS 2D geometric constraint solver with a Teigha for .dwg files client application to provide easy access to constraint solving functionality. A sample application demonstrating a number of constraint-related features can be found on the ODA web site.

To learn more about LGS 2D/3D, visit the LEDAS Web site at www.ledas.com/products/lgs2d.


LEDAS Ltd. is an independent software development company founded in 1999. It is based in the Novosibirsk Scientific Centre in Akademgorodok, Russia at the Siberian Branch of the Russian Academy of Science. A leader in constraint-based technologies, LEDAS is well-known for the computational software components it creates for PLM (Product Lifecycle Management) solutions.

Its solutions include geometric constraint solvers for CAD/CAM/CAE, optimization engines for project management, work scheduling and meeting planning software, and interval technologies for knowledge-based engineering and collaborative design. The company also provides services for PLM markets, including software development, consulting, reselling, and education, and training.

For more information about LEDAS, see www.ledas.com.

LGS is a trademark of LEDAS Ltd. Any other trademarks are the property of their respective owners.

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