D-Cubed: Latest release of the 2D DCM, Version 54.0
Released September 2008
Siemens PLM Software announces the latest release of the D-Cubed 2D Dimensional Constraint Manager (2D DCM), a software component that controls 2D parametric sketches in 2D and 3D design environments. Some of the new features specific to version 54.0 are listed below. A full product description can be found here.
Performance enhancements: parallel processing; spline length constraints
Siemens PLM Software is committed to taking advantage of technology developments where possible to enhance the performance of our components. For example, the ability of an application to run different instances of the 2D DCM in separate threads was introduced in Version 52 in August 2007. This enables independent sketches to be solved in separate processors. This latest release begins the process of using multiple processors to accelerate performance in a single instance of the 2D DCM.
A sophisticated, computationally intensive 2D DCM function enables the length of splines to be solved in a sketch. In Version 54 such a computation can be distributed across multiple processors. The best results will be obtained for splines that have a large number of control points, where the computation can be divided among a number of spline segments. The spline length algorithm can run on four processors in less than 35% of the time taken on one processor. With the spline length algorithm being a part of a full evaluation solve cycle, the time taken on four processors can be less than 57% of the time taken on one processor.
In addition to this ability to use multi-core processors to speed computations involving spline lengths, substantive intrinsic enhancements to the spline length computation time have been made, typically resulting in a factor of two improvement, even on a single processor.
Functional enhancement: extended solution control
Dimensions and constraints alone may not define a unique location for a geometry. For example, a point dimensioned a distance from a fixed line can have two solutions relative to the line direction:
Two solutions for a line-point distance
Prior to this release, the 2D DCM would select the solution based on the initial position of the point relative to the line, though the 2D DCM could then be instructed to switch solution. Version 54 enables an application to define which side of the line the point will always lie irrespective of its starting position. Similar control is provided for circles, ellipses and parametric curves/splines to determine the side on which the dimension applies to the curve. Examples involving a circle and a parametric curve are given below:
Solving to the selected “side” of a geometry
Once an application has defined the “side” of the solution, a signed distance dimension may be used. If the value of the dimension is positive, it will solve on the same side. If the value of the dimension is negative, it will solve on the opposite side. This is useful, for example, when a dimension is set to zero, and then back to a non-zero value, ensuring that it solves to the same side. This is an important capability, for example, when the 2D DCM variational sketch solver is embedded into a history based solving process.
The new capability has extended the wide range of solution control techniques already offered by the 2D DCM. These techniques help users to develop sketches that solve as required and then behave predictably when modifications are made.
Functional enhancement: additional degrees of freedom information for sets
Sketch geometry (lines, circles, splines, etc.) have degrees of freedom that are removed as dimensions and constraints are applied. For example, dimensioning the radius of a circle will remove one of its three degrees of freedom (removing the remaining two freedoms will define the position of its centre).
The 2D DCM already reports degrees of freedom information for individual geometries. For example, if the radius or centre of a circle has not been defined, the 2D DCM can report this information, assisting the user with constraining their model. Version 54 extends this capability to sets. Sets are collections of geometries which the 2D DCM solves as if they are constrained relative to each other without requiring the use of individual dimensions and constraints.
The new information shows users how a set is free to move, helping them to determine what constraints are required to remove the freedoms. Information is provided on the translational and rotational freedoms, including for example, the centre of a rotational freedom.
In the figure below the green set represents a cam, the purple set a follower and the grey geometry is fixed (fully defined). The cam is constrained to rotate about the fixed point and the follower is constrained to translate between the grey rectangles, as shown. The rotational freedom and centre of rotation of the cam, and the direction of the translational freedom of the follower, can now be reported by the 2D DCM.
Degrees of freedom analysis on two sets
The new degrees of freedom information in Version 54 build on a wide range of sketch diagnostics already available. Developments of this kind are important in enabling users to create high quality parametric sketches more easily.
About the D-Cubed 2D DCM
First released in 1990, the 2D DCM is used in most major CAD applications and is widely acknowledged as the leading 2D geometric constraint solving technology. It provides a variational (non-sequential) approach to solving a broad range of dimension and constraint schemes optimised for use in 2D environments. In addition to driving the sketcher in most mechanical CAD products, it is used in the integral design environments of many other applications, such as CAM and CAE systems.
About PLM Components: Parasolid and D-Cubed
PLM Components are software tools that support innovation and promote interoperability in CAD, CAM, CAE and PLM applications. Siemens PLM Software develops these components, uses them throughout its own applications and licenses them to independent software vendors and end-user organizations. PLM Components include the Parasolid and D-Cubed products, widely used technologies that provide 3D part and assembly modeling, editing and interoperability, 2D/3D parametric sketching, motion simulation, collision detection, clearance measurement and visualization functionality. Applications include mechanical CAD, CAM, CAE, mold design, sheet metal, AEC, GIS, structural, plant and ship design, CMM, reverse engineering and sales configuration. For more information, please visit www.plm.automation.siemens.com/open/.
Contact
Jonathon Rimmer
Siemens PLM Software (D-Cubed Components)
Tel: +44-1223-722635