some times i can / can't 'Convert triangel to quads'

i have started to use blender not long ago :] ( two days ), i have used to use max so have expiriance in 3D programs.
now i have noticed that i have a problem ‘Convert triangel to quads’ some times it works some times it don’t :\ i sespect that it have some thingy with the vortex propertis.
can some one expline me plz what can make ‘Convert triangel to quads’ not towork ?

the actions i made when it didn’t work

  1. i del some vortex in a mash ( like a spher)
  2. i have made a tiangel face
  3. splited on of the ages
  4. mark the two new triangels and pressed ‘Convert triangel to quads’

it does nothingy

thank u for any help

It may be that your tris form a concave quad. (It’s a quad in which one of the verts is “inside” the quad. In other words it has angle > 180 degrees.) If it’s so, tris->quads won’t work.

I’ve had this before and have found that if you move one of the vertices just a small amount you can then convert to quads. That assuming you have the same problem I had in this post.

thanks i will try it out when i will back home
thank u very much