Copying one side and pasting opposite

[Antonyman]

I am trying to model a knife and for my blade I have modeled one sid and I was wondering if there was a way to just simply copy that and paste it to the opposite side similiar to the copy and paste posture opposite when animating in 3ds max.

I have tried copying the faces and pasting them and trying to connect the components but it either doesn't work or it's not what I want

This is the knife for reference, I have modeled how the knife tapers inwards and the small indent? on this side and want to just paste it to the opposite.

[damaggio]

You need to combine the meshes first then connect the vertices... Flip the geometry with -x or - z and freeze transforms... Make sure normals are flipped as well .

[Anonymous]

In Polygons menu set under mesh there should be mirror geometry, click on the options box and change the axis to what you need. Also make sure that the object is on one half of the scene so snap the border to the grid.

What Damaggio is saying is correct also, When you want to merge one mesh with another you need to Mesh > Combine.