LEDAS Adds Advanced Parametric Drawing Functions to Version 4.0 of its 2D Constraint Solver

Patterns, directed distances, and orientation/alignment attributes help users of CAD/CAM/CAE applications to fully control constrained drawings.

Novosibirsk, Russia – LEDAS Ltd., the independent provider of constraint-based design tools, component technologies, and software development services for the CAD/CAM/CAE/PLM market, today announced version 4.0 of LGS 2D, its geometric constraint solver. As a core component of parametric drawing applications, LGS 2D allows users to express design intent through geometric and dimensional constraints applied to elements of sketches and drawings.
New Features in LGS 2D 4.0

Version 4.0 of LGS 2D introduces the following new functions: linear pattern constraints, directed distance constraints, and alignment/orientation attributes for most constraints.

Linear pattern constraints set relations between several sub-geometries of equal shapes (e.g. rectangles), aligning and uniformly distributing them along a given direction. Any changes in position or orientation of any one of the pattern constraint’s arguments leads to corresponding changes in other arguments. As with other LGS 2D constraints, a linear pattern constraint is variational, which means it can be combined with other constraints that are imposed on pattern’s sub-geometries. All constraints are solved simultaneously.

Directed distance is a new constraint that generalizes horizontal and vertical distance constraints introduced in previous versions of LGS 2D. It is a ternary (three-element) constraint imposed on any pair of objects (points, circles, or curves) and a line that represents the direction of distance measurement. It can be used to prevent segments from flipping their end points; using a signed, directed distance constraint (instead of the ordinary distance) fixes the desired relative locations of the end points.

Alignment attributes specify whether the tangent vectors of the constraint arguments are co-directed (collinear vectors with positive scalar product) or counter-directed (collinear vectors with negative scalar product). The attribute can be applied to any constraint involving two non-point entities: tangency, distance, parallelism, or perpendicularity between lines, circles, curves or ellipses.

Orientation attributes control whether an argument is positioned to the left or right side of other ones. They are applied to all distance constraints, except point-point distances. Orientation and alignment attributes fully control the chirality (left or right handedness) of constraints.

For developers, LEDAS provides special integration facilities that simplify the job of embedding LGS 2D into their applications. In particular, all members of Open Design Alliance can use the LGS 2D integration module (developed jointly by LEDAS and the ODA) to quickly implement constraint drawing functions that are fully compatible with the DWG file format. The ODA is a non-profit organization that develops the Teigha™ (formerly DWGdirect) software development platform for CAD and other technical graphics applications.

“The new functions in version 4 were ones requested by our customers,” said Dmitry Ushakov, Director of Product Management at LEDAS. “Our customers’ satisfaction with our products is the greatest recognition we can receive. We appreciate their feedback on our components so that we can continue to improve them.”