When is necessary to apply retopology to our models?, seems quite overwhelming for beginners or medium users...Does it all...

When is necessary to apply retopology to our models?, seems quite overwhelming for beginners or medium users...Does it allow you to improve in other aspects in 3d modelling?. One more question, how do you fill up quads from 2 edges? I cannot understand the shortcut you said sorry (A+F?). Thank you.
  • kotoban replied
    We need to retopology when we sculpt a model and we want to use it in a game or animate it.