ZBrushCentral

Create Alpha - Mask By Alpha

ZBrush Usage Questions
#1

I explain my peculiar problem:

I have an imported mesh: Obj1. (exported from Poser as MorphTarget)
I make a clone: CloneObj1
I ‘paint’ a mask over CloneObj1
I do ‘Masking>Create Alpha’ and Geometry>Divide
Then I activate Obj1
I do ‘Masking>Mask by Alpha’ and Geometry>Divide
And indeed both meshes look the same.
I activate CloneObj1 again and do some sculpting.
I export Obj1 as ZObj1.obj
I export CloneObj1 as ZObj1_mt1.obj

I Poser I import ZObj1.obj
and load as MorphTarget: ZObj_mt1.obj
Poser discovers that the Polycount is not the same!

So, I argue, that ZB is not transferring precisely the ‘as alpha’ saved Mask.

Please help me to solve this problem, because ifte polycount can be ket the same I’ll have solved a big sculptingproblem in the making of (more complicated) MorphTargets for Poser.

#2

EL,
I know nothing about morphing in Poser but the first idea that occurs to me is to make TWO clones which “should” be the same, mask the 2nd clone and modify it. Import the two clones into Poser and junk the original .obj. altogether.

Sven

p.s. also, wondering if you’ve tried using masking with a 2nd 3dLayer and exporting that?

#3

Masking by Alpha relies on UVs. It’s possible that slight variations in the UVs cause some polygons to be masked in one mesh and not the other (though I can’t think why this should be the case).

A better way of working would be to use 3D Layers. If you mask your model that masking will be available in any layer you create. You can use the layer to create your sculpting. Indeed, you could create many layers for different sculpts, exporting a different OBJ for each.

#4

Hi both loyal repliers,

I appreciate your response and understand that I was not very clear on the purpose of my need for masking>create alpha and masking>mask by alpha.
It has to do with wanting to be able to make progressive sdiv’s during the creation of a morph target.
As you, Marcus, will probably remember I solved this riddle by using ZProject Brush to shape a clone of the newly formed (multi sdiv) mesh into the form of the starting mesh (which is of a lower sdiv-character). To use the work in Poser I need to make a mesh that has the same form as the original in poser but with the polycount of the latest sculpt. I ‘simply’ push with the ZProjectBrush a clone of the latest sculpt onto the first form. So the form is the original and the polygoncount is the same as the one of the latest sculpt.

I hope to be clear. The proces of ZProjecting is however difficult to say the least. So I went on looking for a more elegant alternative; and that’s where the masking>create alpha comes in.
I thought to have really solved the problem so I could have a real artistic freedom in sculpting multi sdiv morph targets, but, helas. ZB seems to do something with the saved mask, so it will not translate EXACTLY to the cloned basemesh.

I also tried another route: in stead of saving the masked area with the alpha I tried to draw a red spot on a white polypaint where the mask should be and with Masking>By Intensity I define the area for the new sdiv. This red on white polypaint I Tool>Texture>‘Col>Txr’ and use this texture for the clone-basemesh to get the same area for sdiv.

But also here the process failes: no equal polycount. Probably the same backgroundproblem in ZB as with the ‘CreateAlpha and lMaskingByAlpha’.

By the way, when I use the ZBCube as the basis for this sdiv-translationprocess it worked very well. Strange?

I really do suspect that this means some minor attuning of the proces, but not being the programmer of the function I just am at a loss. Could it be possible that Pixolator himself can help me with this question?

I hope I am not asking too much of your attention.
Greetings, EddyL

#5

Update: What I told you about the ZCube doing fine is not altogether true: only with one sdiv it keeps up its good behavior, but when the polygons get smaller after a second partial sdiv ZB becomes inexact here also.

Maybe this helps in solving the riddle?

#6

To make myself even clearer (I really seem to need a solution :wink: ) I repeat the explanation but now with some screendumps:

  1. import PoserCube (exported from Poser as MorphTarget) and clone.

SnagIt_StartMetClone.jpg

  1. Export PoserCube and Clone.
  2. Import PoserCube as new PropObject in Poser and Load as MorphTarget Clone: Helas: “Wrong numer of Polygons”.

Attachments

SnagIt_CreateAlpha1PlusSdiv1.jpg

SnagIt_CreateAlpha1PlusSdiv1PlusSculpt1.jpg

SnagIt_MaskByAlpha1PlusSdiv1.jpg

SnagIt_CreateAlpha1PlusSdiv1PlusSculpt1PlusCreateAlpha2PlusSdiv2.jpg

SnagIt_CreateAlpha1PlusSdiv1PlusSculpt1PlusCreateAlpha2PlusSdiv2.jpg

SnagIt_CreateAlpha1PlusSdiv1PlusSculpt1PlusCreateAlpha2PlusSdiv2PlusSculpt2.jpg

SnagIt_MaskByAlpha1PlusSdiv1PlusMaskByAlpha2PlusSdiv2.jpg

#7

Eddy,

I think you are making things difficult for yourself with partial subdivision. I don’t know precisely why the polygon counts should be different but if the masking is not precisely the same then that would account for it. It would only take the masking of one vertex to screw the whole thing. Why that should be happening I don’t know but I can’t think of a better way to solve your problem than the ZProject way mentioned before.

#8

Thx Marcus for your reply, although it does not answer my question it makes it clear for me that this simple route can not be used by me.

I can indeed work with the ZProjectBrush-technique.
Also I thought of a workflow with partialsdiv of predefinied subgroups in the basemesh. In that case I don’t paint a mask to define an area that has to be sdivided but I Shift-Control select a subgroup of the basemesh and mask that part, then make visible again and invert the mask and finaly partial sdiv the unmasked area. The same thing I can do then with the workingclone on which I do the MT-sculpting:select, mask, visible, invertmask, partial sdiv and go on sculpting in higher res.
This is a good second workflow I guess.

On the other hand, I would really appreciate it if Pixolator or Auric could make it clear to me why the more elegant form doesn’t work as it should.
BTW. I discovered (maybe they understand with this new info better why it’s not doing the trick) that when I use a ZCube or a ZBall and Sharpen the Mask a few times before Masking>CreateAlpha and Geometry>Smt=Off in most cases the trick does work.
If, on the other hand, I make a new ZBRUSH UV (GUV or AUV) all sorts of pollution of the resulting mask after:Masking>By Alpha occur in the new mask compared to the one that was saved before in Masking>CreateAlpha.
Hope for a solution so I can go on making MT’s for my Poser animations that are as Low Poly as possible. As you will know takes doing animation a lot of rendering-time with even low poly objects, so …

Greetings, EddyL

#9

Eddy,

I don’t know if this could be part of your problem or not but I was discovering that even though the poly and vert count was the same, my verts were being reordered somehow…and thus screwing everything up.
I have no idea where or how but it’s the only thing that could have been happening to me. I have no idea if this might be happening to you but maybe something worth considering.
Good luck buddy, keep at it!

Regards,
Ray

#10

Just for the record now, for those still interested in this zb-problem, I found two ways to solve the problem I have/had:

  1. The first solution is defining in advance a sufficient number of small subgroups that together fill the surface of the mesh.
    Then clone, so you’ll have the BaseMesh and the SculptMesh. Start sculpting on the … SculptMesh. If there comes a moment for partial subdivision you simply select (Ctr+Shft), Mask, MaskInvers and SubDivide the subgroup(s) you need in both BaseMesh and SculptMesh. After that both the meshes will have the same (now higher) vertex-count. With the sculptmesh you go on sculpting. If, after some time you need some more refinement on your sculpt, you select, etc again to equal subgroup-areas on the BaseMesh and the SculptMesh, etc.
    When yiu are finished you export both Meshes one to use in Poser as Prop on to which you load the SculptMesh as MorphTarget. QED

  2. The second solution is more ‘elegant’:
    Again a BaseMesh and a cloned SculptMesh. Start sculpting on the SculptMesh. If there comes a moment for partial subdivision you Polypaint on the sculptmesh the area that you want to have subdivided. Then Col=>Txr that Polypaint, Masking>MaskByIntensity, InversMask and Subdivide.
    Then activate the BaseMesh and select the last created Txr and … Masking>MaskByIntensity, InversMask and Subdivide this BaseMesh. What you will see is that you have the exact same VertexCount.
    Then you go on sculpting the partly subdivided SculptMesh and If needed you can repeat this method for on aother partial subdivision and again and again …
    When you are finished you export both Meshes one to use in Poser as Prop on to which you load the SculptMesh as MorphTarget. QED

I think that I finally reached the end of this Thread. Thank you for thinking along.
EddyL

#11

Eddy,
I’m glad you got it sorted to your satisfaction.