[PD] Gem - how to get a concave/convex plane

[Oliver]

>> basically [curve3d] works well, with a minor issue that can be worked
>around. though i don't understand why it's there.
>Certainlly because I made a mistake with S T coordinate when I code
>this object, and you  are the 1st one to notice it.
>I don't know if it's a bug that should be corrected, or a bug that is
>there for so long that it should stay for compatibility.
>anyway, the workaround is easy.
>

Indeed, and yes i too think compatibility is important. 
A suggestion for a possible Future release: maybe you could add something like a "flip_texture" or "tex_coordinate" function to [curve3d]. (would be a great Feature anyway ;-))

Best

Oliver