What is the best way to spacially query the navmesh?

Say I want a character to execute a sideways roll, but only if they have enough navmesh to their right to do it. What is the best way of acheiving that with blueprints?

Should I find the desired final position and see if there’s navmesh there? or is there a better, more native solution to the navmesh system?

I have no idea how good or bad this is yet but found this:

UNavigationSystem* NavSys = UNavigationSystem::GetCurrent(GetWorld());

bool GetRandomPoint(FNavLocation& ResultLocation, ANavigationData* NavData = NULL, FSharedConstNavQueryFilter QueryFilter = NULL);

Have you looked at the Environmental Query System yet? It uses the nav mesh. You didn’t say whether this was for a player or AI controlled charcter, but the eqs system works very well with AI behavior trees. You could have an eqs query find valid points within the nav mesh to roll to and then only if there is a valid roll to point within some [max roll to distance], then execute the sideways roll. Here is a link to the docs on EQS:

https://docs.unrealengine.com/latest/INT/Engine/AI/EnvironmentQuerySystem/UserGuide/