Okay, I have my eyes on these nice set of doors on TSR

Unfortunately, all of them have 1x2 footprint, so they won't center properly on my sim's 2-tile wide hallway.

Now I want to edit them to have 2x2 footprint instead, which means widening the green box but letting the door stay centered.

I've gone as far as cloning the .package files... then I got stumped reading the tutorial footprint and someone's description about FTPT

(1) So, do I still need to edit both the FTPT and the VPXY chunks, or would it be necessary to edit only the FTPT chunk?

Now, inside the cloned .package file, I see 2 FTPT chunks. Checking them with the Footprint Editor (from inside S3PE), I noted that one of the FTPT chunks have its "IsEnabled" flag checked, while the other FTPT chunk doesn't.

(2) Does that mean I can delete the other FTPT chunk, i.e., the one where IsEnabled is NOT checked?

(3) Final question: Opening the FTPT chunk with IsEnabled, I see two footprint areas (attached for your perusal). Do I need to edit both areas, or just the elongated one?

Thank you for your kind assistance!

Look, I'm not very expert on this but I'll try to help.

Dont' delete anything, even if a footprint is not enabled (I never checked how doors work
exactly but I know that some footprints are enabled/disabled by the object's script and it
seems likely that doors too handle the routing/traffic in this way).

To change the "green outline" you have to change the footprint marked as "for placement".
I'm not sure if this will help with your issue though, but, again, I'm not an expert.

Until someone else more competent answers you, you can try (with a backup copy of the
package) to edit just the FTPT entry marked as "for placement". Follow the tutorial and see
my... ehm... embarassing """"contribution""" to it (should still be the last post) if in doubt.

About editing the VXPY: well, that contains the boundary box of the object and usually
has the same coordinates you get from the mesh.

Thanks, @Arsil! That helps a lot, especially with the discovery that Footsie doesn't update the "Upper" and "Lower" parameters.

Now the footprint is properly 2x2... except that I've run into a problem exactly like this: http://modthesims.info/t/377010

(tl;dr version: The door still insists to be placed within a tile, and not between tiles. In other words, instead of the door straddling 2 adjacent half-tiles, I see the footprint straddling a half tile + a full tile + a half tile)

*sigh*