ZBrushCentral

Flip normals button.

ZBrush Usage Questions
#1

Hey there,

How do you use the Flip button to selectively flip the polyon normals in just one group of a tool with multiple groups? When I select just one group individually and use Flip, it at first seems to work, but when I bring the rest of the model back into view the normals I just flipped reverse back again.
#2

To give further background… I’m working on a character model which has elipsoids for eyes. I’ve adjusted all the normals by hand, but when imported into ZBrush, somehow the eye’s normals are reversed. I’m using all the default settings for .obj import. I’ve verfied the normals in several other applications to ensure they are correct, and that it’s not some problem with the polygon modeler I am using, Amapi 7. Hence why I am want to reverse just the eye’s normals. They are a seperate group in the model. But when I single out the eyes and use Flip, it works only until I reveal the rert of the model, at which pont they reverse again.

#3

Bump.

Any ideas on this? Am I just looking at things wrong or is ZBrush not designed to allow for flipping the normals on just partials parts of tools?

#4

I dodn;t know if it works but did you try to mask the mesh (ctrl+shift) and then flip the visible part? Maybe it will only affect the visible and not the hidden part. However, no time to try out…
cheers
LemonNado

#5

Flip will reverse the normals of the mesh masked or not, so the only other way is to selectively make that part of the model visible and then Flip, and that doesn’t seem to work either.

#6

I guess what I’m really asking is, is there a way in ZB to selectively flip a single or group of polygon’s normals without flipping the whole mesh’s?

#7

Actually… I never had the problem and found no solution for that in ZB. I only have the problem in XSI when I create new geometry. I might have to to invert the normals of a freshly created nurbs surface as the poor thing doesn’t know which side I will use. Then, I do not fiddle with normals as it always leads to distortions of the sub-d modles which I cannot tame. I leave the calculation of the normals to the machine.

Good luck!
LemonNado

#8

The only way I can think of is to use MultiMarkers.

Import your object and clone it in the Tool palette. Draw one clone on the canvas and in Edit mode make just the eyes visible. Delete the hidden polys and then Flip the normals. Press Deformation> Unify.

Clear the canvas and draw the other clone. Hide the eyes and Delete hidden. Position and Mark.

Pick up the eyes clone and draw on the canvas. Use the Gyro to position and scale. It really helps if the Scale and Rotation are about right at this point but position is not critical. Be sure to Mark.

Clear the canvas. Make sure the Tool option in the Markers palette is off. Pick up the MultiMarkers tool and draw on the canvas. Use the Gyro to position.

Press Edit and then Move. Locate the red square for the eye pivot and you can click and drag the eyes into position. It is possible to use Scale and Rotate in the same way but this is more fiddly. You can also rotate the whole model by dragging on the empty canvas.

When you are happy with the position turn off Edit. Now be sure to press Tool>Modifiers>Reposition before pressing Make Polymesh. Then new polymesh should have exactly the same number of vertices and groups as before but with the normals facing correctly.

#9

Forget all that, there IS a simpler way, providing your object is symmetrical. Just hide all but the eyes then Tool>Deformation>Mirror (probably just the X axis). Then make the whole of your object visible again.

Can’t think why I didn’t think about it before. :o

#10

Hmmmm Mirror… Never played with that… Gahhhh… there goes the afternoon.

Thanks Marcus :wink:
Lemmo