Needing help with a Map error

Hello, so recently I began to edit and create a map. I then moved the .bsp to my maps folder in Garry's Mod when done editing and I got this error..
CModelLoader::Map_IsValid: Map 'maps/rp_city8_v3.bsp' bsp version 21, expecting 20
map load failed: rp_city8_v3 not found or invalid.

I am using Source Film Maker (SFM) to build the map. So I don't know if its because of that or if something else is wrong.. If anyone could help out, that'd be great.
(And I don't know if this is the right place to have this thread)

 

I'll move this where it belongs.
If you don't find good help here, you're gonna want to ask on the Facepunch Mapping forum.

 

Alright, thanks!

 

SFM is extremely fidgety with anything other than TF2 maps due to the multiple versions of Source over the years. As someone who doesn't use SFM I can't really help you, best thing you can do is to decompile the map, recompiling it with the TF2 version of Hammer and trying that.

 

I will try this when I get home.

 

I also forgot to add that when I tried to load the .vmf file in Source SDK, hammer closes at 5% loading. So idk if this is part of the issue or if its something different.

 

Not sure if you still need help, but a few things.
Firstly, you can't open BSP (Binary Space Partitioning) files in Hammer Editor, you need to decompile the map so it becomes a VMF (Valve Map File). Basically, VMFs are compressed maps so Hammer can open them and edit them, otherwise the size of a map is too big and it'll crash hammer.
Since you're using Source Film Maker's SDK to use Hammer, you have to compile it by pressing F9 and doing the rest of the blahblah. It'll air the fuck out of your CPU (Depending on the map size, guaranteed it'll go to 100% CPU) and it'll compile the map into a BSP, which allows games like Garry's Mod to open and play them.

Judging by that error, a few things could have happened. I'm not exactly sure which but SDK's model viewer is really shitty. I would recommend using Nem's Tools, specifically Crafty to view the BSP/VMF. Whenever you try to open a BSP in SDK, it may be too big, so it'll mostly crash the pre-loading process.

http://nemesis.thewavelength.net/index.php?p=45 <- Crafty

 

You got those the wrong way around buddy, VMF files are for hammer, BSP files are for the game itself.

 

Oops, yeah, switch that. My bad.