make a mother mold for casting silicone rubber molds for a planter mold

a 3D Design includes 3 parts

1- outter walls to contain the original part
2- original shape to be reproduced out of the silicone rubber mold
3- cavity management peice to fill blank inside of the planter original preventing unneccessery silicone rubber waste.

part should be mechanically functional as following

1- ease of assemply
2- a tight fit design to prevent silicone rubber leaks or parts free float.
3- correcrt spacing and parameters ensure a good silicone rubber cast.

to be provided as ready to slice STL File.