The following assumes you want a smooth object in TurboCAD format.
If you are working with Pro or Platinum, then you can try converting it to a Solid. That has worked... okay... for me on the few occasions I have tried it.
Alternatively, and depending on the complexity, of course, you can use the Snap functions to make high resolution 2D traces, then Extrude them.
For instance, the attached object was provided as an STL. I used the Circle by 3 Points tool to get most if it traced, then extruded to the other end. The inner details took a bit more time, but it was exact... and smooth.
TC Pro Platinum 2017, 2016 & 2015 (all with LightWorks) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1