UPDATE: People have been asking for more screenshots, I have been too busy to supply them but I have found a youtube video by ponihkio ( a recap of his TGIF lobby) containing gameplay from Catalyst.

Here is the video, skip to 4:08 for Catalyst. YouTube- Forgehub TGIF 13 Recap

This is a screen shot of my BTB map catalyst (my map).

It emphasises vehicle combat but in a very different way to hemmorhage. Here is a comparison.

Hemmorhage:
very little vehicles vs infantry combat.
infantry are helpless if caught in the open.
vehicles are helpless if they being shot at from a ledge with a DMR or sniper.
infantry's main weapon vs vehicles is the the DMR
infantry combat is very long range.
One large main area where all the combat takes place.
Best for infantry to stay put and snipe.
Some very powerful weapons like the sniper and wraith.

Catalyst:
lots of vehicle vs infantry combat.
infantry and vehicles always both have a chance in a battle.
infantry's main weapons against vehicles are grenades and hijacking.
Infantry combat is nearly exclusively medium range.
Several main areas which one can easily and fluidly move between.
Best for infantry to advance and stay together.
No very powerful weapons, there are revenants and rocket hogs but they are not as powerful as the wraith or sniper on hemmorhage.

Teams:
designed for 2 teams of 5 to 8 players each, but upto eight teams are supported.

Gametypes:
This map is prmarily designed for slayer with but assault, multiflag, invasion slayer and rocket race work well on it. It also supports oddball, crazy king, territories, race, stockpile and headhunter.

Layout:
The map has a central area (depicted above) connected on two (opposit) sides to a ring which ecompasses the map, the other two sides enter onto bases which favour infantry but can be entered by vehicles (the rest of the map is mainly vehicular). The backs of these are connected to the ring around the map. All the exits from the central area restrict sightlines (keeping comabt medium range), but not access. Spread out across each base are a revenant, 2 ghosts, 2 warthogs, a rocket hog and 2 mongeese. There are also smaller bases on the outside of the ring which contain a man cannon into the center and an assortment or warthogs, ghosts and mongeese.

Information on testing:
This map made its debut on the 29th April TGIF being played twice in Pinokhio's party (both times with slayer, once with AR spawns, once with DMR spawns) and it was generally very well received. I have since updated the map (no major changes but more gametypes supported) and the Berb has said that he would like to use it for his TGIF party on 13th May.

Other than this the map has had not testing, so please download, test it and give feedback.

other pictures:

overview of the map

Vehiclular area on the ring, tunnels lead to centre

view from behind red base. Bottem left: red vehicles, right: another vehicular area on the ring

the outside of red base (the map is symetrical so blue base looks the same)

the inside of red base