[Inkscape-user] Metallic cone - perspective tool?

Hi all, I am new to Inkscape. I intend to create an object, that looks like a cone, made of metal. I made an illustration of my problem, here it is: https://www.semilab.hu/fileshare/download.php?file=4d5a2cd6af0883.9642163... I have already created something that looks like a metal tube (from the side). It is a square, with a linear gradient fill. The fill has three stops: two black at the edges and a white in the middle. It is fine, but when I try to turn it something like a cone, I get stuck. The only thing similar to what I want is to turn the square to path, then move two of its corners near to each other. But this doesn't change the gradient fill, so the tip of the cone will be all white, instead of a narrower gradient of black-white-black. What I would need is something like the perspective tool in Gimp, that distorts the whole object, including the fill, but I didn't find it in Inkscape. Is there something like this, or can you suggest another way to do what I want? Thanks: Abel