How do you combine designs with parts made in multiple pieces of ECAD?

[TheUnnamedNewbie]

I'm working on a design in which we use different pieces of software.
I want to use Altium for the more "general" PCB design part. The connections between components and such put into a schematic, and then I can use the usual flow for PCB design.

But we have a milimeter wave structure that was designed in Ansys HFSS. How do I best import this into Altium? Or is it best for me to work with some other software to put it together? I could do it in HFSS but it is an absolute pain in the behind to do such a thing in HFSS, and it is far easier to make mistakes.

Any good resources on this? most of what I find when I look this up is how to export designs from altium into HFSS for simulation in HFSS, but that is not what I need here (and can't, it would simply take too much memory, we are already pushing what we can do with our little 1 cm long structure).
 

[Rerouter]

can you move it through an intermediate format, e.g. kicad lets you export or import copper layers as a dxf file,

[Araho]

I'd probably try to export a DXF from HFSS - the DXF format was made for this exact purpose (Design eXchange Format), but I have no clue whether or not HFSS support it.

Create a new component in Altium for your structure, where the copper elements are created from importing a DXF-file. Define the pins of your component, and add a pad in the copper structure for each pin, just like you'd do normally.