Quote - Well, if the ends are n gons (polygons with more then 4 verticies, then there's your problem right here.. for poser you need to use only 3 or 4 point polygons.

If it was me, and you only needed a cylinder, why not just scale and use the included one in poser already?

not quite true. you can use an N-Gon on the end of a cylinder right there without an issue. remove the center Vertex and let it be a 5-16- whatever  sided N-gon and it'll work just fine.

trust me. it'll render just fine.

Airport security is a burden we must all shoulder. Do your part, and please grope yourself in advance.