Create Butterfly geometry with geo “set multiple breps” boundary mesh shrink

grasshopper butterfly
1

Hi community,
there is something wrong with boundary mesh, it shrinks when i set the geometry with multiple breps. but it works fine when it’s only one brep.
really appreciate some help :pray:

Screenshot 2024-04-12 224920
Screenshot 2024-04-12 2249201165×1295 253 KB

2

already solved it. i need to increase the cell size in wind tunnel grading