Anyway, this is a render of the Poser Pro 2010 cone. The first render was with smoothing off, the second partial render (inset) was with smoothing switched on.

Is this just down to bad geometry?

I never use the smoothing.  I find it tends to distort the geometries too much for some reason.

Quote - I never use the smoothing.  I find it tends to distort the geometries too much for some reason.

That's often okay... but I want a proper, smooth cone in my render, not an arrangement of flat triangular polygons and hard edges.

The P7 cone renders fine in P7, but both the 7 and 8 cones are droopy
when rendered in 8 with smoothing on.  (The picture shows the 7 cone
rendered both ways.)

I try to use smoothing as little as possible, turning it on via the CR2 only
for the pieces that (1) need it and (2) don't go bonkers when it's on.

Thanks for the tests, David... I never even considered that it might be the smoothing algorithm itself.
I'll report it to SM. In the meantime, I'll try different smoothing angles, see if it makes any difference.

The top point is actually a very small open circle,
and the bottom circle is unwelded.

Attached TXT is an OBJ file; rename to something like
NewCone.obj and then save it as a prop.  

Thank you! I'll give that a spin in my scene a little later.

It's a big improvement over the Poser cone, but I'm still getting some problems - see screenshot. There is some barely discernible ballooning - I had to put a straight edge up against the cone edge on my screen to be sure of this. Also, the surface gradient is nowhere near smooth near the top end. The Poser hi-res ball, on the other hand, is showing nice smooth shading all over.

Perhaps Poser doesn't like the long thin polygons? Not sure...

Anyway, I don't want you to spend any more time on it, just thought you might be interested.

d3d's cone (comes with some later versions of poser) doesn't deform on smoothing.
these later versions may not work well with a vertex at the junction of 20 or 32 triangles,
hence d3d's axially-segmented cone also has an empty multi-sided polygon at the tip
of the final segment.  too small to see excepting under extreme magn.

Thanks, Miss Nancy. I didn't know about D3D's props. As you say, the cone works fine.