Masking low polys not selecting the right ones(blured)

[system]

Hi, i want to use Fibermesh on a low poly mesh. But is not working as expected. Here is a replica of the problem with a simple cylinder:

1.Ctrl+Shift and Drag, for selecting the polys

2.Now the half is visible

3.Masking with Ctrl+A (MaskAll)

4.Here comes the problem: the mask is selecting more polygons as expected (half of the cylinder)

5. And here the problem raising at the Fibermesh

So, my question: is possible to have a hard mask(now is something blurred) with Zbrush?
What i ve tried:
-RGB,Z Intesity: 100 %
-sharpening the mask(doesn t help) with Sharpen Mask
-using the Ctrl + drag (stil not working,blured)

Any help appreciated. Im getting crazy with this problem

Attachments

[Altea]

Zbrush makes always mask transitions between verts. This mean it is not possible to get rid of this transition if you only have 2 verts in the side you want to avoid.

There is not sharp separation between faces with masking, but there is with hide face. Hide the area you don’t want and mask the remaining one that you want to use for hair. Now create the fibermesh without unhiding. Preview is not enough, you need to create the hair. Once created the hidden area won’t have any hair.