ZBrushCentral

Screwy backface masking

ZBrush Usage Questions
#1

OK. So I’m trying to ‘thin’ a membrane style wing.

I know to use ‘backface masking’, but it looks broken to me. (ZB3.1, PC)

Using the standard brush, no BFM, and ZAdd, I get both the topside (edit side) and underside of the wing affected (lifted up, or pushed in if viewed from the bottom). So, no problem, I turn on BFM, and try again. Now only the topside is affected, great so far.

But I want to make the wing thinner. So I’m using ZSub. With BFM mask
and ZSub, the topside (edit side) is totally unaffected, and the underside
gets pushed out (away from the brush)! Not what I want at all.

Surely this is broken?

Please tell me if I’m missing something. Right now I’m stuck.

G.

#2

it is broken…in3.1

you can’t use a Zsub with backfacemasking on

you’re better off using the action line to make the whole skin thinner

#3

It works fine, if a little counterintuitively - just set BackMaskInt to -100 when using ZSub.

#4

Groan. OK. Thanks goast666. I’ll try mask and move.

#5

Wups… Or maybe what Marcus suggests

Reverse the polarity Scotty! :smiley:

Thanks Marcus.

G.

#6

Yep. -100 on BackMaskInt works a treat. I was assuming that slider
ran 0-100 as a percentage. Doh!

Kinda weird, but it works.

Thanks again folks.

G.

#7

thanks Marcus! Good to know.

#8

Just a heads up. Noticed another oddity about BFM.

You can apply a mask using Ctrl-Drag with BFM on (+100). But to CLEAR
parts of the mask using Ctrl-Alt-Drag, you need to invert the BFM to -100
again.

Really confusing if you accidentally leave BFM on!

G.