ZBrushCentral

Masking Voodoo: Lasso, Rectangle, Green Rectangle...?

ZBrush Usage Questions
#1

heyas!

can somebody explain to me some of this masking voodoo? i haven’t found any answers on the usual resources.

i go to the brush menu selection, i pick, say, lasso mask. it tells me blah blah ctrl key blah blah right. i understand that.

now, when i hold the ctrl key and try to draw a mask, one of three and a half things happen:

1: the mask draws out as a lasso mask.
2: the mask draws out as a rectangle mask.
3: the mask draws out as a green rectangle and chops off part of my model.
3.5: the mask switches between the lasso and rectangular modes as i’m drawing.

what i don’t get: WHYYYYYYYYYYY???

problem number two… oh, this has to do with the clipping tools. these do voodoo, too.

i select a what is it…? oh TRIM. i select, for example, the trim lasso. the problem? half the time when i select what i want to cut/trim/delete off the model, it SAVES that part of the model and deletes the REST of it. so then i try to draw the trim lasso around the part i want to keep. and then it deletes the part i selected. (ie: the part i want to keep!)

i thought maybe it mattered if i drew the thing clockwise or counter, but no… it still baffles me and keeps behaving unpredictably.

help much appreciated!

#2

a) Ctrl is for Masking. To select a masking brush, hold Ctrl and click the large Current Brush thumbnail. You can then select which masking brush you want to work with. Some masking brushes will give a masking rectangle if you start off the model.

b) Ctrl+Shift is for Mesh Visibility (which give a green/red selection shape), and the Trim, Slice and Clip brushes. Hold Ctrl+Shift and click the large Current Brush thumbnail to select the brush you want from Select, Clip, Slice and Trim options.

For an outline of mesh visibility see here:
http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/mesh-visibility/

For the Clip brushes see here:
http://docs.pixologic.com/user-guide/3d-modeling/hard-surface/clip-brushes/

For Slice see here:
http://docs.pixologic.com/user-guide/3d-modeling/hard-surface/clip-brushes/slice/

For Trim Curve brushes (Trim Curve, Trim Lasso, Trim Rectangle and Trim Cir*cle) see here:
http://docs.pixologic.com/user-guide/3d-modeling/hard-surface/clip-brushes/trim-curve/

HTH,

#3

wait…

i’m NOT deleting any part of the model? just hiding it??

okay, i see.

CLIP is going to smush (or stretch) the model to the clip line.
SLICE is going to ginsu knife through the model and create two (or more) pieces without moving anything.
TRIM removes the chunk of model.

i’ve never ctrl-click or shift-ctrl-clicked the brush selector thing. i just click it, and when i pick a mask brush or the CST brushes, it automatically assigns them as the ctrl or shift-ctrl brush.

wait.

how do i know the difference between when im hiding the model and actually doing one of these CST things to it?
wait, the trim tool always trims, doesn’t hide. the SELECTION or CLIP brushes can hide. okay, so how do i know if i’m HIDING or CLIPPING?

when i’m doing the lasso thing (and it’s behaving as a lasso) the shading is light or dark, which i’m guessing is the same as green or red. only when it turns into a rectangle is it green (or, if i hold the alt key, red).

is green/red hiding/unhiding, and light/dark is masking/CSTing vs inverse masking/CSTing?

okay.

i still do not understand why, when i select specifically the LASSO version of the mask/cst tool, it sometimes draws rectangles, sometimes draws freeform lasso shapes, and sometimes switches between the two.

it’s not whether i start on the model or off, because i’ve tried it both ways, it behaves the same (erratically, to me) either way.

OKAY, i got it. apparently, it changes if i press, release, and/or repress the ctrl key, and when i think i’m holding down the ctrl key, it’s actually pressing and unpressing.
am i not supposed to be holding it down?

#4

AH, that’s interesting. I’ll need to check on that behaviour. If I knew about it I’d forgotten. As you say, tapping Ctrl will switch between lasso masking and a selection rectangle (green).

I think it’s best to avoid tapping Ctrl. You can let Ctrl or Ctrl+Shift up and continue drawing the mask/selection. You can also press the spacebar to move the mask/selection, provided you don’t let up the mouse button.