optistruct模式重复

Pattern repetition is a technique that allows different structural components to be linked together so as to produce similar topological layouts.

To achieve this goal, a master DTPL card needs to be defined, followed by any number of slave DTPL cards which reference the master.  The master and slave components are related to each other through local coordinate systems, which are required, and through scaling factors, which are optional.

Other manufacturing constraints, such as minimum or maximum member size, draw direction constraints or extrusion constraints, can be applied to the master DTPL card.  These constraints will then automatically be applied to the slave DTPL card(s) as described in the next sections.

定义在主卡片上的各种制造约束自动地施加到从属卡片上去。

Local Coordinates Systems

Local coordinates systems are generated by providing four points.  These points can be defined either by entering explicit coordinates or by referencing existing grids, as follows:

1.	CAID defines the anchor point for the local coordinates system.

2.	CFID defines the direction of the X-axis.

3.	CSID defines the XY plane and indicates the positive sense of the Y-axis.

4.	CTID indicates the positive sense of the Z-axis.

The definition of the fourth point allows for both right-handed and left-handed coordinate systems, which facilitates the creation of reflection patterns.

Right-handed coordinates system

Left-handed coordinates system

Alternatively, local coordinate systems can be defined by referencing an existing rectangular coordinate system in the CID field, and by defining an anchor point in the CAID field.

Note that if the fields defining CFID, CSID, CTID, and CID are left blank, then the global coordinates system is used by default.  The anchor point CAID, however, is always required.