How is it possible to smooth continuous boundary lines of membrane cuttings?

Answer

The perimeter of membrane cuttings is described by boundary lines. These boundary lines can be as follows:

  1. globally defined boundary lines of the assigned membrane surfaces or
  2. retroactively introduced cutting lines for dividing the cuttings on the membrane surfaces
The cuttings can only consist of a global line definition or retroactively imported cutting lines, or of mixtures of both types.

Figure 01 - Border Lines of Cuttings

The global boundary lines are untouchable due to their fixed geometry description (arc, circle, spline, etc.) and are thus also implemented in the design of the plane cuttings.

On the other hand, subsequently introduced cutting lines are based on the FE Mesh of the surfaces assigned in the cutting line specification and have no influence on the mesh itself.


The cutting units encircled by boundary lines and cutting lines take over the FE Mesh of the assigned surfaces for flattening. Since the cutting lines run over the FE elements themselves, independently of the global mesh in the boundary zone, the edges of the original FE elements can not be used to describe the cutting edge definition. In this case, the affected FE elements within the cutting line area are divided by the cutting lines.

Depending on the orientation of the cutting line, the FE elements are split in the middle or almost on the edge. Since the FE elements on the edge can cause some problems with geometry, a certain tolerance limit has been entered for the decision. This checkbox controls the critical length ratio between the FE edge length specified by the cutting line and the original edge length of the FE. If the ratio is smaller than the given restrictive value, the cutting line refers to the original FE node.

Figure 03 - Smoothing

This fact may lead to an "Irritation" of the cutting line when the cutting lines are passing close to the FE element edges. This situation can be optimized by reducing the given limit of tolerance.


Keywords

Cutting Zigzag Cutting line Boundary line Continuously Smoothing

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