Vary line with Z-axis for imported SVG file
In OpenSCAD you could create a bevel using the minkowski transformation by transforming the curve using tapered shape such as a pyramid or as I do below a tapered cylinder:
minkowski() {

  linear_extrude(1)
    import(&quot;drawing.svg&quot;);
  
  cylinder(h = 20, r1 = 10, r2 = 1); 
}