Wen it is right time to do UV-s?

ISUther

Hello,

I am confused when it is right time to do UV-s?
Should i do UV-s start of sculpt or end or sculpt or mid?
As i understand i need to have retopo done to model so topology is good (as i understand with not perfect topology applying UV-s may be complex).

kanga

If you are talking about a model like a game character, then you may need uvs to organize patterns on your hi poly model, while you are working on it, so zbrush uvs om some parts. Usually when your hipoly model is finished and has diffuse (polypaint) applied you would send a decimated copy to an external app for retopo. Unless you like doing retopo in zbrush itself. In the external app you build a new/efficient mesh over your hipoly copy. Finish the retopo, uv it and send itto your HD for baking. 

ISUther

I have not done retopo. 
So i diont know how this actually works. 
I am planing to do textures in Mari. (planing to learn that one too)
But i know that before i can bring my model to mari i need to create UV-s to my model. 

I know that zbrush UV-s are bad. 

But now to talk about retopo. 
Is retopo same as decimation in zbrush? If no is the zremesh >> append to low poly model the details named as retopo?

I am confused. 
Sorry for this.