ZBrushCentral

Masked Polygroups Problem

ZBrush Usage Questions
#1

Hello there I’ve been sculping at the version 4R7, but at some point I realised that these polygroups are masked, but the thing is: It is locked there…

For the sake of explaination let’s stablish two “points”, the first: when I hit ctrl + click (mask inversion hotkey) once, and the second “point”: when I hit it twice. at the first point this strange polygroup mask is active and at the second point it’s not.

if I use the mask brush to delete a piece of this masking, the ctrl + click only works inversing the selection in the mask region on the polygroups. When I use the mask brush to delete it all, ctrl + click shifts between the region masked and unmasked, exactly as explained at the beggining.

Does anybody know why did it all of a sudden got masked, and how can I solve it?

Thanks,
Arthur.

#2

I couldn’t say how it happened. All I can do is remind you that ctrl-dragging then releasing a mask marquee in open canvas clears all masking. So do that. Ctrl clicking the canvas will invert a mask, or if no mask is present, it will mask everything visible.

Beyond that I would need pictures to even begin to speculate.

#3

I tryed ctrl + drag as well, but it returns to the case where I delete all the masking. both points of ctrl + click are between the polygroups piece masked in that way and unmasked, It seems a little bit like ctrl + click is only working in that piece of topology / polygroup. I Still did not figure out how to fix it.

#4

Wait, are you saying there is a polygroup you want to mask, but cannot?

  1. Are you certain that polygroup is part of the active subtool?

  2. Are you using LIve Boolean mode? It interferes with the display of active masking.

#5

No, I’m saying that ctrl + click should work in the entire mesh, and not only on that specific piece of polygroup.

And till what I know, I’m not using booleans at all.

#6

Pics?

#7

Sorry the links, but I’m not achieving sending pictures directly, perhaps some internetal issue or other problems. but here it is:

This is how it looks like with polygroup view activated ( note that the masking borders follow the topology lines):

Reuploaded bellow

This is after I use the mask brush to erase some of it:

Reuploaded bellow

This is how it looks like after ctrl + click (note that it only afected the damaged piece and not the rest of the mesh):

Reuploaded bellow

Note that the area has a awkward shade of yellow, differing from the rest of the mesh:

Reuploaded bellow

but even using a merge on the area, even the coloration changing and matching, the mask problem continues:

Reuploaded bellow

The URL is a little bit awkward but the “blob:” stuff is actually part of the link address

#8

Unfortunately, you can’t post remotely hosted images in the Zbrush forums. You must use the attachment function.

Just edit your previous post, and Ill check back.

#9

This is how it looks like with polygroup view activated ( note that the masking borders follow the topology lines):

mask problem 2.png

This is after I use the mask brush to erase some of it:

mask problem 3.png

This is how it looks like after ctrl + click (note that it only afected the damaged piece and not the rest of the mesh):

mask problem 4.png

Note that the area has a awkward shade of yellow, differing from the rest of the mesh:

mask problem 5.png

but even using a merge on the area, even the coloration changing and matching, the mask problem continues:

mask problem 6.png

#10

OK, none of those polygroups look vital. So:

  1. Ctrl-drag a mask marquee in empty canvas, then release, to clear mask. Likewise, Tool> Masking> Clear.

  2. Polygroup > Group Visible to unify your poly groups on the visible mesh.

Apply masking as desired.

I dont know how you got here, but if that doesn’t get you back on track, we’ll have to examine your mesh for errors or unintended geometry.

Question: Do you have any sort of auto masking active on the masking brush…for instance “mask by polygroup:”?

#11

Indeed it did Unify All of the polygroups, but the strange mask’s still there :frowning:

#12

I cant tell from the pics, but does the dress have thickness? Is it 3 dimensional or only a single layer of polygons with open holes? Zbrush doesnt really like that kind of geometry for sculpting, and a number of weird things can happen with it, especially near edges. If this is the case, you’ll want to give it some thickness either through poly extrusion, or masking everything and doing a Subool > Extract.

Have you examined the geometry with Tool > Display properties > double sided off to make sure there are no flipped normals?

Could you have unwanted, overlapping geometry in that area? Click Tool > polygroups > auto groups, and that will separate any unconnected meshes into separate polygroups. If you then see a different color in that area from the rest of the dress, shift -ctrl click elswhere on the dress to hide it and see if anything remains in the problem area.

#13

maybe something strange is going on with your geometry, this masking bit seems weird
2017-06-22 19_07_46-Masked Polygroups Problem.png

#14

The Robe has no thickness, it is open at some points like the collar, the sleeves and the bottom. Following the steps you’ve told me, the topology and normals look OK (thanks for the tip on showing double sided normals tho), and the affected area does not seems to be separate nor overlapping as well, even after these steps, the mask is still there. And I’m not sure, but it seems to be affecting the normalmap bake as well since Zbrush only created a piece at the normalmap image plane and applying it to an UV mapped lowpoly version of the robe, the piece baked is somewhere around that mask area.

#15

Well, I’ll give you a couple things to try, but honestly, I’m pretty sure it’s just the fact that it’s 2d open geometry that’s caused the weirdness. As I said, ZB wants geometry to be closed and 3d for optimal sculpting. Sculpting over open geo gets weird at the edges, because the points there dont always do what you want, and the internal point ordering can get messed up where ZB sometimes thinks geometry in one place is connected to geometry someplace else on the model. ESPECIALLY if you happened to start modeling that dress from one of the parametric primitives like the cylinder. Unwelded/Unfixed cylinder primitives are highly bug prone.

That said, try:

  1. Geometry > Modify Topology > Optimize points

  2. Geometry > Modify Topology > Align Edges

  3. Geometry > Mesh Integrity > Fix Mesh

If none of those do the trick, you’ll have to remesh it into a closed 3d mesh with depth, and delete unwanted geometry after you’re done sculpting, if you really can’t have it. If you need help with this, let us know.

#16

Even after these steps, even though the program asked me to freeze the subdivisions while the process is taking place, and that the “fix mesh” has corroded some parts of the mesh on the sleeves, the mask’s still there haunting my project.

#17

OK, time to ditch that geometry.

  1. If you absolutely don’t want to part with the 2d open geometry, duplicate it as a subtool and run the duplicate through ZRemesher set to the resolution you’re comfortable with being the base geometry. If you lose detail, dont worry you can subdivide it, then project the detail back from the original with the Subtool > Projection palette.

OR

  1. If you want to add depth, Duplicate your model as a subtool, then select Zmodeler. Delete all the but the lowest level of subdivision (or whatever you want your base geometry to be), as ZMod doesn’t work with subd levels.

With ZMod set to Polygon > QMesh > Island, click on a polygon on the inside of the duplicate mesh, and drag it inward slightly with enough depth that backface masking will work well with it. Notice that the resulting extrusion is its own polygroup now, so you’ll be able to easily hide/mask/or delete the dress interior as need be.

*Note: Normals often get flipped when extruding inward, so make sure to view it without “double” on to check for weirdness. If they are flipped, click Tool > Display Properties > Flip to fix.

Subdivide the resulting dress as desired, and project detail as above. Due to the added thickness, you may have to increase the .dist slider in the projection palette.

Or

  1. Mask the entire mesh , and go to Tool > Subtool > Extract, and preview various settings with depth until you find one you’re happy with, and hit “accept”. Because of the weird nature of your mesh, I suspect you might get some weird results with this in that area. At any rate, this doesn’t produce geometry as nice as the other methods, so you’ll want to run it through ZRemesher as in point #1 to establish sub d levels and clean up the geo.