Update vertex buffers?

I have a mesh defined by Position and Index buffers. I make a geometry for it, and translate it. But the mesh vertices stay the same in the buffer. So if i use getTriangle(i,t) then t.get1(), t.get2() and t.get3() are giving the old positions and not the ones after the translation. Can I somehow update the buffers after the translation, or how can I get the new values?

You can get the new ones by multiplying the transform of the geometry with the triangle coordinates. If you want to modify the mesh buffers directly then you can do something like: