we are using the JT-IFC-JT translator , but...
the problem is that ALL (+foul words...) AEC software are "saying" that they support IFC4 but NONE which i have seen so far actually support Advanced Brep, which is part of the IFC4 standard.
So , the only system i have seen so far supporting advanced Brep is NX (! ) using this standalone JT/IFC translator.
So, the sad story is that if "they" send you an IFC file, - do not expect the result in NX to be good.
Ask for a .dwg file instead. that is by my experience better. Or step, if possible.
The imported result is, depending on the sending system , a mixture of solids and facet bodies. the solids only have planar faces. ( no circular or complex shapes)
Advanced Brep ? = Solids with "more than" flat faces. i.e, cylinders will appear similar to cylinders instead of polygons.
You can deliver IFC files if you have the JT to IFC translator, ( you export a JT file from NX and then run this JT-IFC translator)
and, the IFC file will be pretty good quality. ( Do not take that as the guarantee that the receiving system handles it well though...)
The translator is standalone, you do not need the TC Vis . The translator has a price.
You can export JT from NX with , i think whatever CAD license you have, then you run that translator "on prompt". = IFC file
The freecad, was you intention to use it as a translator , or simply switch to using Freecad instead of ... ?