Selecting top faces only of multiple objects

Thanks again for the time you spent on the script :) I tried it for 1 object and it works perfrectly but for many independant objects in the scene it did not function unfortunately.

What I did is select all objects and run the script then I hit 4 but I see no selection being done?

Thanks !

You need to select single object and then press 4.

Yes I did select a single object and pressed 4 but only the roof of that object was selected and not all the other objects roofs

Is there anything I need to change in the script?

Thanks

Here also script and test file (*.obj and *.ms)
You welcome!

:)

Options:
"Angle Threshold spinner" -- angle beetven face normal and Z-axis
"Max Height" -- select only faces which center position is > Max Height

try(DestroyDialog ::bgaRoll)catch()
rollout bgaRoll "selectObjTops"
(
local poGFN = polyop.getFaceNormal, poGFC = polyop.getFaceCenter
spinner spn_ang "Angle Threshold:" range:[0,360,5] pos:[5,5]
spinner spn_heig "Max Height: " range:[0,360,0] pos:[4,25]
button btn "Select T O P S!" width:150 pos:[5,45]

fn getDirAngle v1 v2 = (acos(dot (normalize v1) (normalize v2)))
fn getTops obj ang: elev: =
(
local topFaces = #{}, norm = [0,0,1]
if isKindOf obj Editable_Mesh do (poGFN = getFaceNormal ; poGFC = meshop.getFaceCenter)
for f = 1 to obj.numfaces where getDirAngle norm (poGFN obj f) <= ang do
(
if abs ((poGFC obj f).z-obj.min.z) >= elev do append topFaces f
) ; obj.selectedfaces = topFaces
)
on btn pressed do
(
if selection.count > 0 do
(
for obj in selection where isKindOf obj Editable_Poly or isKindOf obj Editable_Mesh do
getTops obj ang:(spn_ang.value) elev:(spn_heig.value)
)
)
)
createDialog bgaRoll 160 70 style:#(#style_titlebar, #style_sysmenu, #style_toolwindow)

This is a test code.Select all objects (E-Poly or E-Mesh) and run the code.
Then go and select any object and press "4" on keyboard (face sub-object mode)

for o in selection where isKindOf o Editable_Poly or isKindOf o Editable_Mesh do
(
topFaces = #{}
gfc = if isKindOf o Editable_Poly then polyop.getFaceCenter else meshop.getFaceCenter
for f = 1 to o.numfaces do
(
if (gfc o f).z == o.max.z do append topFaces f
)
o.selectedfaces = topFaces
)

Attach a screenshot to see with what kind of objects you have

Thanks so much, I tried the script as you mentioned but did not get the selections of all top faces. I followed your tutorial by selecting all objects in the scene, run the script, then select 1 object and I hit 4. But only the selected object top face/roof was selected and not all of the objects top faces.

Here is a screen capture of a portion of the objects (buildings) that I need to select the roofs (top faces) only