Hello, this is my first real map. I’ve made some things before, but nothing really worthy of mentioning here. Now after years of practise in Hammer (before that in GTKradiant) I finally got something to release so I can finally leave this behind me.

As the name might explains this is a more functional flatgrass map for your sandbox needs. I personally think this one is unique because it has support for literally anything you want to do in a gmod sandbox. Of course some maps allow this too, but on alot of popular building maps i’ve encountered alot of space issues. E.g. Water is only one small square or the traintracks are too narrow in turns or tunnels which makes them derail. Or there are dead-end roads or the flyspace or tunnels are too limited in size which is boring and simply sucks.

In this map you won’t have this problem! I have tested it with big trains, trucks, airplanes, boats and everything is usefull. As long as you build in realistic proportions, shipping cargo containers throughout the map won’t be a problem.

Some technical info:
Name: gm_functional_flatgrass
BSP size (incl. textures): 37.5mb
Required games: Gmod (HL2)
Supported gamemodes: Sandbox
Max players: 128 (wouldn’t recommand lol)
Build time: ~350 hours

Some features:

  • Biggest Skybox possible for flying or whatever big thing you wanna make.
  • Supports day and night with the ent. paint tool
  • Optimized using hints, areaportals, func_details, max draw distance etc to prevent fps drop even when noclipping through the map.
  • Has 3d skybox with ‘infinite’ water. Which makes it look big and nice but also usefull for navigation in air!
  • Lots of roads which have plenty of room for trucks etc.
  • Lots of water which is useful for small boats, amfibious vehicles and even huge ships.
  • Police station with jails and everything needed (some doors start locked from inside).
  • Many buildings such as: a cinema, club, stores, garages etc.
  • Bridges that can be opened/closed.
  • Building areas that can be closed with doors/areaportals so you can build your vehicles in peace.
  • Giant flat underground building area for big expensive things that you shouldn’t build right next to spawn if there are lots of players.
  • Giant underground wasteland terrain with mountains and some water for your offroad or tank battle needs…
  • Giant underground area for car testing needs.
  • Underground trainyard with stations and switches and turns and everything you need for trains.
  • Inside pool which can be filled/emptied for whatever reason that may be.
  • Buttons etc for alot of things.
  • Elevators for players or vehicles. Even trucks work, as long as they’re not too long.
  • All the space is used. The water is made as deep as possible with keeping the tunnels as high as possible.

The positive:

  • Great for everything you need in a Gmod Sandbox
  • Great for building everything
  • Great for driving small cars and big trucks
  • Great for driving boats and even huge ships are no problem, there is plenty of water.
  • Great for flying. The airspace is biggest one possible.
  • Great for trains. There are big turns and the tunnels are high enough for the double deckers from drumdevil for example.
  • Great for using everything together as some sort of transportation game.
  • Great for a default sandbox map where you won’t have to change maps because a certain feature is not supported or limited.

The negative:

  • The lighting is not professional, i’m simply not good at it. I think HDR is too bright and also a headache to optimize so I released it LDR. This won’t really matter if you want to use it as a good sandbox map.
  • Textures might be a bit boring and there might be some minor lighting bugs I couldn’t fix.
  • There could happen a weird reflection bug when you use Scars on the map. I have no further clue about this.

Great overall sandbox map for everything you need. Please let me know what you think of it. I am not going to release a new version though as I grew tired of it for now.


  • I used some road textures from “roadpack”. There are 5 textures from “roadpack/europe” inside the .bsp that are packed with pakrat.
  • I used the PHX tracks as traintracks template, eventhough i’ve edited the switches.
  • The rest is just HL2, gmod and me.


SOURCE: (read the readme!!)

I might be a bit late but I would just like to say that the your thread is just about as functional as the map.
Seriously I love well organized and in-depth release threads like this one.

This is also very impressive for a first released map. All in all you get all the stars.

for the lighting, try angling the skybox light a bit to cast some cool shadows, also, make sure you are compiling with the final compile settings correctly for max quality

and one little feature suggestion. I am not sure why I never see them in sandbox maps such as these, but I also enjoyed using cranes in gmod (like the one from hl2). It would help your map stand out a bit.

My very first map actually was just a crane, its terrible but it should show you how one is could be made. (I admit I actually cleaned it up before uploading it because when I loaded this old thing up, it was so cluttered and messy it was cringe worthy).

Anyways, heres the DL link if you are intrested or just want to take a look.
I also added a func viscluster to speed up compiling (very handy for wide open spaces)
(right click, save as vmf)

Thanks for the replies, tbh i kinda wondered why nobody replied in the first place and I only got ‘funny’ ratings.

As for the crane, i’m not putting one in. It does have support for them to be build anywhere though, i’ve already made them ingame. Especially the outside of the map shouldn’t have much more because i’m afraid it will bring fps down. The hl2 crane isn’t so hard to make though, but the controls are a bit meh and you’ll be better off making a realistic dock crane.

Some have requisted more AI nodes too. I do have some but not throughout the entire map. I thought the limit was 1000 or so?

So i’ll probably do an update soon. But thanks to the workshop it gets updated automaticly for everyone. If you have it on your server, just open the new gma and upload the new bsp to the server.

Thanks all!

That’s amazing for a first release! I wouldn’t worry about the repetitive textures or light too much, it’s very difficult to light up huge areas and texture flatgrass maps. Great job, I’ll test it out!

If anyone is interested, i’ve uploaded source for viewing, learning or expanding or whatever.

I’m probably not gonna do fixes or other versions anymore. If you are, be sure to read the readme if you want to release a version though for obvious reasons.

Hope this helps anyone!