build error in vs2017 for using RecastDetour

[marsxu1984]

Error CS0246 The type or namespace name 'RecastDetour' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 21 Active
Error CS0246 The type or namespace name 'RecastDetour' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 1 Active
Error CS0246 The type or namespace name 'RecastDetour' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 1 Active
Error CS0246 The type or namespace name 'RecastDetour' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyRDPathfinding.cs 1 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 50 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 74 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 119 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyRDPathfinding.cs 426 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 432 Active
Error CS0246 The type or namespace name 'MyRecastOptions' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyRDPathfinding.cs 430 Active
Error CS0246 The type or namespace name 'MyRecastDetourPolygon' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 51 Active
Error CS0246 The type or namespace name 'MyRecastDetourPolygon' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 91 Active
Error CS0246 The type or namespace name 'MyRecastDetourPolygon' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 745 Active
Error CS0246 The type or namespace name 'MyRecastDetourPolygon' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 51 Active
Error CS0246 The type or namespace name 'MyRecastDetourPolygon' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 91 Active
Error CS0246 The type or namespace name 'MyRDWrapper' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 60 Active
Error CS0246 The type or namespace name 'MyRDWrapper' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 81 Active
Error CS0246 The type or namespace name 'MyRDWrapper' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 456 Active
Error CS0246 The type or namespace name 'MyRDWrapper' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 138 Active
Error CS0246 The type or namespace name 'MyPolyMeshDetail' could not be found (are you missing a using directive or an assembly reference?) Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 52 Active
Error CS0103 The name 'MyRDWrapper' does not exist in the current context Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 640 Active
Error CS0103 The name 'MyRDWrapper' does not exist in the current context Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 647 Active
Error CS0103 The name 'MyRDWrapper' does not exist in the current context Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 845 Active
Error CS0103 The name 'MyRDWrapper' does not exist in the current context Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 853 Active
Error The command ""D:\projects\SpaceEngineers\Sources\SpaceEngineers.ObjectBuilders....\Build\Tools\SGenAutoResolve\SGenAutoResolve_x86.exe" /a:"D:\projects\SpaceEngineers\Sources\SpaceEngineers.ObjectBuilders\bin\x86\Debug\SpaceEngineers.ObjectBuilders.dll" /d:"D:\projects\SpaceEngineers\Sources\SpaceEngineers.ObjectBuilders\bin\x86\Debug\VRage.Game.dll" /b /v" exited with code -532462766. SpaceEngineers.ObjectBuilders
Error CS0019 Operator '>' cannot be applied to operands of type 'method group' and 'int' Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 282 Active
Error CS0019 Operator '==' cannot be applied to operands of type 'method group' and 'int' Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 817 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\VRage.Dedicated\bin\x86\Debug\VRage.Dedicated.dll' could not be found SpaceEngineers.Dedicated D:\projects\SpaceEngineers\Sources\SpaceEngineers.Dedicated\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\SpaceEngineers.Game\bin\x86\Debug\SpaceEngineers.Game.dll' could not be found SpaceEngineers D:\projects\SpaceEngineers\Sources\SpaceEngineers\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\SpaceEngineers.Game\bin\x86\Debug\SpaceEngineers.Game.dll' could not be found SpaceEngineers.Dedicated D:\projects\SpaceEngineers\Sources\SpaceEngineers.Dedicated\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\Sandbox.Game\bin\x86\Debug\Sandbox.Game.dll' could not be found SpaceEngineers.Game D:\projects\SpaceEngineers\Sources\SpaceEngineers.Game\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\Sandbox.Game\bin\x86\Debug\Sandbox.Game.dll' could not be found VRage.Dedicated D:\projects\SpaceEngineers\Sources\VRage.Dedicated\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\Sandbox.Game\bin\x86\Debug\Sandbox.Game.dll' could not be found SpaceEngineers D:\projects\SpaceEngineers\Sources\SpaceEngineers\CSC 1 Active
Error CS0006 Metadata file 'D:\projects\SpaceEngineers\Sources\Sandbox.Game\bin\x86\Debug\Sandbox.Game.dll' could not be found SpaceEngineers.Dedicated D:\projects\SpaceEngineers\Sources\SpaceEngineers.Dedicated\CSC 1 Active
Error CS1579 foreach statement cannot operate on variables of type '?' because '?' does not contain a public instance definition for 'GetEnumerator' Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyExternalPathfinding.cs 825 Active
Error CS1579 foreach statement cannot operate on variables of type '?' because '?' does not contain a public instance definition for 'GetEnumerator' Sandbox.Game D:\projects\SpaceEngineers\Sources\Sandbox.Game\Game\AI\Pathfinding\MyNavmeshManager.cs 284 Active

it says missing RecastDetour lib for navmeh navigation, I had used this lib before.
Do I need to compile dll form https://github.com/recastnavigation/recastnavigation by myself?

[jeffvella]

I was able to find this dll by installing the game on steam, then going to the SteamApps folder where the game is stored and all the needed dlls are there. You may or may not have to go into the properties>betas tab for the game in steam and select another opt-in version such as Mod API beta improvements.