IIRC selecting a face and then clicking mirror mirrors from that face. Could be wrong. I tend to use the mirror modeller instead.
yeah, i thought that's how it's done.

only used it once on a large shivan corvette, which turned out by far the best model i've made thus far, so i think i will be using it again.

Checking and fixing double verts mean at least 10-20% of the whole modelling time, so a tool like this would be a dream. And am I wrong or you may use it to generate lods too?
it can be used for making lods, but i generally do that in TS - grab a small edge or even entire face and weld together. in that context of use it's the same in both proggys, cept in blender you would then have to re-add the textures, meaning it isn't really worth it

uhh this is something I'd really like to have in TS!
well, there is a _sort_ of way to do it i found when desperately trying to solidify a high poly lucifer a number of months ago. what i did was save the object to .3ds format (i think) then re-import it into TS. obviously it's a bit of a hack, but it worked in this occasion, where 'chunks' of faces were making up the model. so if i welded any verts to each other, the constituting faces would dissapear, sorta messing up the whole uv mapped mesh.....

Mirror modelling means that the modifications you do on one half will be automatically reflected to the other half, being always able to create a temporary mirrored object or to finally unify the two halfs.
well, not quite automaticly-you have to click the little update mirror button thing, but yeah, it's really useful for symetrical models.

i imagine it could make some really interesting things happen if done right-see the underside of the hatshepsut.