Topic: trim solid hatch

[domenicomaria]

https://drive.google.com/file/d/1d6Jo1TwBHYGuMODuZgvQNroVoAFeVGdt/view?usp=sharing

. . . the version. 1.1 . . . 

[xdcad]

if i select a point on the boundary,
the no-entry symbol appears,
and trim doesn't work.

while,
if i select a point OVER the hatch
the no-entry symbol does not appear,
the part of the hatch that will be trimmed,
changes its color,
and the trim command, works well.

My question is :
via Vlisp,
what have I to do
to get an internal point,
in the part of the hatch
that i want trim ?

I had thought that I can generate the outline boundary of the "solid hatch",
divide it into segments, (when there are curves),
check the direction of the list of points,
calculate an internal parallel to the list of points
that represents the boundary,
and take a point from this new list of points. . .
. . .
but I hope there is a simpler way

Let you fully master handling HATCH:

https://www.theswamp.org/index.php?topic=58727.0
https://www.theswamp.org/index.php?topic=58726.0
https://www.theswamp.org/index.php?topic=58725.0