How can I paint material accurate on the mesh?

[TargetLost]

I designed an object with 123D Design and let the UV map generate by Blender.
The import and painting in Substance Painter 2 works fine and I can paint the material however I have a hard time to get a clean border between the different regions/material.

Now teh smart UV mapping of Blender did very good job to separate the UV-Mesh regions into islands. So all I want it to do is to fill a UV polygon mesh island with one material.

If I just paint the material I have to sitch to a very small brush size for the island border but also then it draws over to another UV-island that is the logical mesh nighbour.

I found a polygon fill where you can directly fill that polygon island unfortunatly just with a base color.

Q: Can I get him to fill the island with a material instead a color? OR can I swap the filled color with a material later.


If not is there another way how I can tell him that I want to paint on my isolated island only?
Truely to switch to the smallest brush and painfully draw the polygon borders with it can not be the way to do it or is it?

Thanks for your help.

[僕の名前 (仮)]

Make a fill layer with mask and then paint on mask.

[TargetLost]

Thank you.

As one that uses that program only on a few occasion the concepts of it are not as intuitive and easy presented as I would like them to be.

Got it working with the mask, Took me a time to figure out how exactly this mask operates.

I figured that as long as I have truely isolated mesh island it works perfect!!

On the Non fully isolated parts it fails worse than hand paintig.
It makes very visible stairs on the border line between the two materials which is astonish because it is exactly thesame material in every aspect I just choose two different colors.

So if I combine those two technics mask for islands and painting for non fully isolated part I should get it to work.

Funny thought that there is no direct fill with material tool instead just one fill mit color and than haveing to use and work with a mask.

Such a direct fill with material on polygons tool would simplify the process a lot and eleminate the need for those many mask layers.

[僕の名前 (仮)]

Using masks and different fill layers is non-desttructive workfow. You can tweak and change material when mask stays same. If you'd directly paint material on layer you would lose that.