Limiting the NavMesh.CalculateTriangulation Mesh to an "Area" Around Player

Hello. I was wondering how I might limit the rendering of the mesh that is created at Runtime when using the NavMesh.CalculateTriangulation function. Basically I want to provide a variable that will control how far away from the player the max extents of the mesh is rendered. Like when you click on an army in Total War style games and it shows you how far that unit can move. Currently I can visualize the mesh at Runtime but I cannot figure out how to mask it to only be a specific radius around the player. I would like to use the NavMesh since I can assign higher cost values to areas such as woods or swamps (which would limit the units speed through those areas) and give me a visual representation that a unit will move much slower through those areas compared to open ground.

Thank you,