Weird geometry when using Mirror + skin modifiers I'm following a course from CGCookie (Basics of character modelling). I'm trying to pull one of the vertices backwards:

there's a mirror modifier on, as well as skin and subsurf.



All the geometry gets warped:



Same thing happens when I'm trying to extrude another vertex from the bottom one.

Can anyone please help? I tried asking the question on the course's page, but the mods deleted it for some reason.
Skin Modifier is generating the geometry from the root vertex (marked with dashed circle around it), and if its not on the mirror axis that will generate mesh errors.

To fix that select the vertex of the groin area and in Skin Modifier click Mark Root.