In Editable Poly, you could just select all vertices and hit Connect. Basically does a triangulate (without requiring script). You definitely don't want to convert to Editable Patch. No no no.
Resurrection! I've automated this process by creating this macroScript (i've linked it to my own quadmenu) macroScript TriangulateSelection category:"Mesh Editing" internalcategory: "Mesh Editing"tooltip: "Triangulate Selected Mesh"buttontext: "Triangulate Selection"(macros.run "Modifiers"…