code: def is_convex(mesh):
      
      # don't consider zero- area faces
      nonzero = mesh.area_faces > tol.merge
  
      # adjacencies with two nonzero faces
      adj_ok = nonzero[mesh.face_adjacency].all(axis=1)
  
      # make threshold of convexity scale- relative
      threshold = tol.planar * mesh.scale
      # if projections of vertex onto plane of adjacent
      # face is negative, it means the face pair is locally
      # convex, and if that is true for all faces the mesh is convex
      convex = bool(mesh.face_adjacency_projections[adj_ok].max() < threshold)
  
      return convex
docs: Check if a mesh is convex.
  
      Parameters
      -----------
      mesh : Trimesh
        Input geometry
  
      Returns
      -----------
      convex : bool
        Was passed mesh convex or not