How to build a gantry

Hi everyone,

I’m trying to figure out the best way to model a gantry in realvirtual and I’d like to check if my approach makes sense.

Mechanical setup

• Think of a classic gantry crane

  

• In my machine I have
  

  • Two separate X-axes at the bottom (front and back rails – green arrows).
    They can move independently in X, but in normal operation they should behave like a gantry pair.

  • On top of them sits a Y-axis stage (blue arrows) that moves sideways.

  • 

• The Y-stage is physically connected to the X-axes via joints in Unity.

• The CAD / Unity hierarchy is basically flat – the Y-stage is not a child of one of the X carriages, so I cannot rely on parenting to move it together with X.

Control side

• I have separate drives / axis values for:

  • X-front

  • X-back

  • Y-stage

• The requirement is:

  • When X moves, the whole Y-stage must move with it.

  • Y should still have its own motion relative to the gantry.

Questions

1. What is the recommended realvirtual setup for this kind of gantry?

2. How should I combine this with joints?

   • Should I keep the joints at all, or would you recommend a purely kinematic Axis/Drive setup for this use case?

Any hints, best practices, or “don’t do this” stories are very welcome.
Thanks in advance!