Workflow

To project large textures on a surface object with one click right in Spot Tool, with normal Brush mode, just click once, otherwise you ‘smear’ the texture. 
Set the Stroke Mode to Stamp or Stamp Drag instead.

Make a new layer. Draw with Paint Tool, Lasso Mode.
Then in Vertexture Settings, activate ‘Apply VerTexture Interactivley’ and then edit Scale, Rotation, U and V Shift for positioning.

This video displays the transfer in short:

You can export textured sculpt meshes WITHOUT baking from factures room as fbx. But the materials need some tweaking.

Start in Modelling Room and use ‘retopo to sculpt mesh’. Also low polycounts look good. 
On export from Factures Room hit ‘Export to’ or ‘Export -> Export Scene’ as fbx and hit ‘Don’t decimate’.
It looks great if you have displacement maps to feed in the materials!
Because of the tiled textures you can make big lanscapes/objects with high detail, which is otherwise not possible.

How does it work?

In this example we use Blender, but it should be working almost the same in other softwares.

3Dcoat generates duplicated polygons of the underlying mesh when painting, which can be selected in Blender by the Material Slots in Edit Mode. You can use this to move the layers in the 3d View.
As Example move the snow mesh a little higher then the ground. (as seen in the lower picture)

The FBX Mesh has Vertex “Attributes”, which can be used for driving the color and transparency of textures.  The ‘vertex alpha value’ is used for fading the textures together.

This Vertex Data derived by the  Attribute Node — Blender Manual can be used in the Material.

In Blender you can plug in the “Attribute” Node (finds in add nodes) Multiply the Color and plug in the Alpha.

Use VertexPaint ‘Ease Alpha’ and ‘Add Alpha’ for repairs. It is helpful to plug in the Attribute Node directly into the Material Output temporarly.

You can also use Select Connected (ctrl+L) and Invert Selection (Ctrl+I) and hide (h/Alt-h) to isolate poly layers.

It is a bit fiddly if you use a lot materials, so start easy. But now see how you can use factures.

In 3DCoat, If you make your own vertextures it is easier to find and reload the other texture slots in the 3d App because the diffusive channel already contains the right folder location to the other pbr files.