That's why I said to move it away from XYZ=0The Mirror Tool that @EllenM mentioned is great but the copy is right up against the original and is welded to it.
Then you must see Frank Beckmann's Boolean thing.A complex "parametric"model would be nice to see.
I moved the model away from center, saved the file as an .stl, so, no layers. I relaunched and added a symmetry modifier. I then saved the file as an .stl again, relaunched and deleted the original model, then moved the file where the other was at center.How do I make a mirror copy of a complex model?
To be honest, this is how I have done it, but I usually copy the model into a temp document instead of saving a duplicate. I like Ellen's latest mirror post best, so far.I moved the model away from center, saved the file as an .stl, so, no layers. I relaunched and added a symmetry modifier. I then saved the file as an .stl again, relaunched and deleted the original model, then moved the file where the other was at center.