Snapping vertices to a plane, is it possible?

I have been working on half a character model but quite a few vertices of the open edge of the mesh have gone out of alignment. Is there a simple way to get them to all snap to the same X position, but not alter their Y,Z coords?

Yep, place cursor in smart point, select all vertices you want to flatten and do a constrained scaling along x


Thankyou :smiley: