Hatch fills the island ...why?

Rhino Rhino for Windows
1

Hi,
V5
despite exploding and analysing, also project to cplane the inner shape and delete original etc, I am unable to fill with hatch this shape and have a white island.

If I draw a box and then another within I can get it to behave on that.

Unable hatch island out.3dm (28.5 KB)

Steve

2

_Hatch needs closed curves to work, your inner island curve is an open curve.

c.

3

Good find by clement.

Use CrvStart and CrvEnd to mark the ends of the curve. In this case it appears to overlap.