I want to know how you can detect what race a player chooses in the pre-game lobby.
ex. A player chooses protoss for a UMS game, and they start with a Protoss Nexus on the map.

Can they only start with a Start Location and nothing more? Or is it more complicated?

The condition 'command' should be what you're looking for. You can use it to detect whether the player has a nexus, hatchery or command center at the beginning of the game, and do your actions as you would like.

I think he wants it to detect if the player is protoss and then place a nexus. For this, I have no fucking idea ;D

Wait...
Does that mean that on every UMS map it automatically has those units at the very start?
Or can you only have the Start Location for them at start?

Can you start the map with other units already owned by that player?

Doubtful. This is UMS, so you won't start with anything.

I don't know of any good way. The only thing that pops into head is EUD, which is never a good thing.

If there was a difference in race other than the gui, it would be easy. Perhaps you can start with all 3, and have the player build drone/scv/probe to start with that particular race?

Well, I know that in the World of Starcraft RPG it has a system like this. You can choose your race a start, and it decides what you do in-game.

If you select your race it creates the respective home building at the start location I think, so maybe the map just detects that they have either a hatchery/nexus/command center, kills it, and bases the rest of the players triggers from that.

Yup, when the player's race is set to 'User select' that player will ONLY have the main building of his race and 4 workers. Any preplaced units/buildings for that player will be removed.

So, if I were to have that player have other units besides the hatchery/CC/nexus, I would have to give it to them by trigger?

exactly. Preplace for P12 (or other players), then use give action.

Okay then. Tyvm!