I mean... the 3D model is an important part for an item, of course, but it is absolutely useless if the game logic/game code does not include a function to use it. Considering that OpenArena already has got the "personal teleporter", which is an "holdable item" useable by simply pressing ENTER, I imagined you meant to create a new feature, a teleporter that works like a weapon. Maybe I misunderstood.
Creating a portal weapon is not so banal, there are a lot of things to do and check, the first one being planning how it should work in practice.
DO NOT LINK[/b]) h t t p s : / / openarena . wikia . com/wiki/Team_Arena]Team Arena source code -that ended up in OpenArena
DO NOT LINK[/b]) h t t p s : / / openarena . wikia . com/wiki/The_Mission_Pack]Mission Pack, and from which many features (the 3 weapons, the 4 runes...) have been imported directly into OpenArena main game- contains an hidden, unfinished "portal device" (a different thing than the existing personal teleporter), that maybe we may complete and use in future OpenArena versions. But not only its model is unfinished,
probably also its game logic (I'm not sure), so it is not a quick thing to do, and it would require work from Sago.
Or you were simply planning to change the current "personal teleporter" model (a 3d "T") with something that resembles a weapon instead of a letter?
UPDATE: Okay, I understood what I misunderstood. I misinterpreted your image (I did not expand the thumbnail before). My fault, sorry. It's not representing an item to pickup, but a sort of "teleport booth" where the player has to enter. So yes, it would simply be a 3D model that would be used during map creation. What I previously said is out-of-context with what you were talking about. Sorry again.