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Any solution to that Reversed Normals issue?

ZBrush Usage Questions
#1

Thank you for any help on this in advance:

I’m having an issue with thin geometry that I’ve had before: normals reverse on import creating issues with morphing and updating to a higher rez. Below is a detailed description of the problem. What I’m looking for is a solution that works with geo that has been subdivided and needs to morph from one shape to another (my geometry explodes as I uprez it).

I have a model that I need to animate its shape (its a sheet that will have multiple blendshapes). The new OBJ I’m importing is from MAYA. In maya all normals face the right direction, point order matches. There are multiple OBJ shapes that I use to import into into this tool- all of them work except one. I am aware that this problem has existed for awhile- and unfortunately, due I suspect to the need to morph and uprez the model, clicking on tool>display>flip doesn’t seem to help me. I’ve adjusted the settings of import, but at this point I haven’t found a setting that solves the problem.

thank you once again
Craig

#2

No answers? I’m sure I didn’t stump anyone… maybe I wrote too much? Keeping it simple- how do you insure geometry normals don’t flip on import?

#3

i know this is probably a bit late, but make sure your transforms are frozen before exporting from maya. I had this problem in XSI recently where I mirrored something over on X (so it had a -1 x-transform), and it looked fine in XSI until I imported it in zbrush and found that the normals had reversed during the mirror process.

#4

Testure

Wow- thank you for the belated reply :slight_smile: . I agree with your assement of the negative flip being a common normal problem. My main concern is the issue I’ve had with “thin” or one sided geometry- like a cape or cloth. Even with the transforms frozen- I have noticed that they flip on import/export. From what I’ve heard- I just have to live with this and fix it on the fly. If anyone has some advice, feel free to share.

Craig

#5

I often get the same problem that you are experiencing with thin geo or with geo that has a lot of open edges. Here is something that you might try. Import your object or tool as usual. Go to Tools/Display Properties and select “Double”. This is basically like turning “Backface Culling” off in Maya, and it will allow you to see the polygons the way you intend. Don’t worry about turning it off when you export. Its only a display option and does not actually flip the normals of your object. Hope this helps.

#6

I"m having the same problem with reversed normals with a mesh that does indeed have many open edges. Unfortunately this is a problem if I try to reimport my base mesh cuz zbrush crashes. Also if I try to bake out cavity maps, zmapper does nothing when I click on ‘create cavity map’.