Select bottom polygons of a editable poly box help

Thanks too. I was having the same issue. If it doesnot work I will make the following.

Give them a very high depth like 20m or 200m so I can select in poly edit mode from teh side view and delete al the faces selected and I hope only the top faces will be left.

EDIT: solved

finally!!

I've not used the scritp provided but found a workarround. I use this for road pavement lines. Import from your cad file. MERGE SAME SPLINE TYPE PER LAYER. this will speed up importing specially if you've lots of them.

Mesh rendere with rectangular rendere with zero heigh, planar.

Apply EDIT MESH modyfier

Select per faces. aaand

CHEKCK ignore backfacing.

Place yourself in botton view (if you want to delete botton side)

Rectangle selection

ONLY botton faces are selected.

Elete.

DONE!!

Thanks

Select your converted splines and run this code
(works on E-Poly and E-Mesh)
fn deleteCupFaces =
(
if selection.count != 0 do
(
--call polyop and meshop function before start for-loop
local delPoly = polyop.deleteFaces, delMesh = meshop.deleteFaces
for obj in selection do
(
local fC = getNumFaces obj -- get number of Faces for each item in selection
if isKindOf obj Editable_Poly then (delPoly obj #{(fC-2)..fC} delIsoVerts:true) --E-Poly method
else if isKindOf obj Editable_Mesh do (delMesh obj #{(fC-3)..fC} delIsoVerts:true ; update obj) --E-Mesh method
)
)
)
deleteCupFaces()