I believe that the steps to creating an infection map in Halo Reach and Halo 4 are very similar, and here is how you do it in REACH:
First, you need to create a map in forge world. Place buildings, weapons, or whatever you think will be good for infection. Next, you need to save that map and return to the Forge Home screen at the main menu.
Select the map you just saved and make sure that the game type is set to "Infection", not "Basic Editing". (NOTE: In Halo 4, I believe the gametype is called "Flood")
You must then reload the map. Next, place RED spawn/respawn points where you want the survivors to start from. Each time you place a Survivor spawn point, make sure you go to the settings and change the TEAM of the spawn point to red, and make sure you go to the advanced settings and change the LABEL to inf_spawn. In that same box, it may also be beneficial to change the GAME-SPECIFIC option to TRUE, but it is not required.
Next, place blue spawn/respawn points for Zombies in the same manner as above.
Lastly, regardless of whether or not you are making a SAFE HAVENS infection map or not, you will to go to the OBJECTIVES panel, select HILL MARKER, change its SPAWN SEQUENCE to 1, and make sure that you change its LABEL in the advanced settings to inf_haven. Place it somewhere on the map. (NOTE: This may not be a requirement for infection maps on Halo 4)
Next, play your map in custom games and have fun!
You cannot make your own maps in Halo: ODST, it doesn't contain forge world. Halo 3, Halo: Reach and Halo 4 all contain forge world.
A genuine code for a copy of the Horizon Map Pack for Halo 4 is available to you upon purchase of the map pack card from a store, such as Target, or you can purchase the map pack directly on Xbox Live via the Store on the Halo 4 main menu.
Well, it is 343, and it is true :( Bungie is GONE now :( and 343 made a new map pack for Halo: Reach. They are almost 100% sure they are going to make a Halo 4! :) (too bad it is not Bungie)
No, they will not make a Halo 4... But 343 Games will!
Halo rights are owned by Bungee. Technically Halo 4 is "Halo ODST"
yes it will be HALO reach or ODST
they are going to make halo 4 but bunige will not be making that
Left 4 Dead, or Zombie House.
Halo 4 was Halo ODST (orbital drop shock trooper) there are many more halos than 3. 1-Halo 2-Halo 2 3-Halo 3 4-Halo ODST 5-Halo Wars 6-Halo: Reach Halo 4 was already made, and idk if they will make the 7th because at the end of reach, everyone (and i mean literally everyone) dies and master chief is already gone sooo.....idk. but halo 4 was made.
Gravemind and the flood do not make a reappearance in Halo 4. Instead we get the Didat and the Prometheans.
Yes, it's a pretty big possibility that they will make, not one, but two more games as Halo 4 marks the beginning of the Reclaimer Trilogy.
The map "Forge World" in a Halo: Reach is just a large map with nothing on it, other than like trees and rocks and stuff. There are only 4 items which you can place in Forge mode on "Forge World". 3 of which are in the spawn category.