How to use HatchPatternTable

currently i try to create a hatch. But i cannot find any predefined HatchPattern.
If i call FindHatchPattern i do not find any Patterns. Also the the list of Patterns is empty.

int hatch_index = context.m_doc.m_hatchpattern_table.FindHatchPattern( pattern_name );
ON_SimpleArray<const CRhinoHatchPattern*> patterns;
context.m_doc.m_hatchpattern_table.GetSortedList (patterns);

Do you have any hints how to find the predefined Patterns?

Rhino has a set of pre-defined hatch patterns that are added to the hatch pattern table on-demand. That is, they are not added to the hatch pattern table until you run the Hatch command and select one of the patterns.

Does this help?

ok, yes i thought also that the table would be filled on demand. but even if run the hatch command, the table is still empty afterwards.

so the conclusion for me is to generate a new hatch pattern if i use a hatch in my code.