Ring Hatch: the hatch lines will be marked from outside to inside of
the object contour in a circular and skewing manner. As shown on the left of
Figure 3-8.
Ring filling: filling lines is object outline, from outside to inside cycle
offset fill. As shown on the left of Figure 3-8.
Optimized bidirectional hatch: It is similar to bidirectional hatch,
but the ends of hatch lines will connect. 3-8。
Optimized bidirectional hatch: It is similar to bidirectional hatch,
but the ends of hatch lines will connect. As shown on the right of Figure 3-8.
Bow shaped filling: Similar to a two-way fill, but there are
connecting lines between the ends of the fill lines. As shown on the right of
Figure 3-8.
Fig.3-8 Left is Ring Hatch filling, Right is Optimized bidirectional hatch filling
Optimization Gong type hatch: similar with Gong, will jump in null
place. 3-9：
46 / 217
    "