Region unoin error

hi,I have some problem at the component region union.
I guess the region union maybe have the tolerance,so my rhino absolute tolerance is 0.001. i also simplify the curves’ control point before i put them region union.
in most case, it works.

but in this file,There’s little I can do.I want to know the reason .
my commersial version is 6.30.
region (9.7 KB)

Hi TriRocks,

instead of region union, you could try clipper:

region union (9.1 KB)

Thanks for you answer.
i kown clipper is well,but’t i only use the GH component to graphics processing.
I have summarized some reasons why region union didn’t work.
This time I’m really not sure why region union didn’t work.

i guess region union should have a Input parameter about tolerance,just like this clipper component.