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What is the best way to mirror this object and weld with no lines?

ZBrush Usage Questions
#1

Hello everyone. I’m still pretty new to Zbrush and have a lot to learn. I just experiment with Zbrush to make jewelry as a hobby. For now my workflow is to scan or buy 3d objects and then sculpt on them or add things.

I get models like this one which is only one sided and hollow. If I want it to be solid and two sided, I use the Zmodeler method and pick “close” and the “concave” and then I can boolean them together.

The problem is that I get a dividing line type of mesh. Is there a better way for me to make this fish solid and not have to smooth out the lines all by hand which will distort my geometry before I divide it?

Thanks for any help. One picture shows the one sided and hollow model I start with and then the other picture shows the weird dividing line I get. hollow%20half

line

#2

M&W will always form a dividing line at the intersection of the mirror plane. The seam becomes noticeable if the contour of the surface makes an abrupt change at the intersection, rather than a smooth curve or flat plane.

The lower poly you’re working at, the easier this is to fix. With Zmodeler, you can delete the center line that causes the seam: Zmodeler >Edge > Delete> Edge Loop Complete.

Zmodeler doesnt work well with high poly meshes though. Some other options are:

  1. Move the half mesh left/right slightly on the x-axis before mirroring it. You may find a mirror plane that produces better results or is easier to fix.

  2. Determine at what point your mesh is becoming distorted near the 0 axis. Select the Trim Curv tool, and trim vertically near the middle to cut off the distorted mesh portion near the mirror axis. This will leave you with a sort of soft, ugly mesh fill at the trim line, but that’s ok because it is a separate polygroup. Switch to move mode (W). In Move mode, ctrl click on that new center-facing polygon fill. It should now be unmasked while the rest of the model is masked. Make sure the gizmo is centered and aligned properly, then ctrl-drag along the x axis. This will cleanly extrude out a portion of the mesh along the X axis that can then be mirrored and welded from side to side, resulting in a flatter seam along the center which may be easier to smooth out.

  3. M&W the fish in its current form. Duplicate that fish as a subtool, and Zremesh the duplicate to low enough resolution that that dividing seam disappears in the geometry. Subdivide the duplicate fish with enough SubD to hold the detail, then project the detail from the original on to the fish AFTER masking the center portion of the target to keep the seam detail from being projected there.

#3

Wow, thank you for dropping so much knowledge. I will try all of this later today when I get a chance.

For trying the Zmodeler center line deletion method, (Edge>Delete>Edge Loop Complete), so I try these steps immediately after making the hollow half of the fish solid? (After I use “close” and pick “concave”)? I’m not sure when to try these steps.

Thank you, I will try all of your methods to see what works best but I just wasn’t sure when to try your first idea.

Thank you!

#4

For deleting the center loop, you would M&W the fish as usual so it forms a complete, closed mesh, then delete whatever geometry in the middle is causing problems. You’d have to do this before adding any additional SubD levels. Editing topology doesn’t usually work with multiple subdivision levels.

If the intersection in the middle is more complicated than a single edgeloop, consider pushing the mesh along the x axis into the mirror plane slightly before performing M&W. This may cut off the problem geometry leaving you with only a clean edgeloop to deal with. You can always re-adjust the X scale of your mesh afterward.