Normals invert on export
by Chuck Thomas · in Artist Corner · 06/27/2006 (9:11 pm) · 13 replies
My character exports. There are no errors in the DMP file and an STL check comes up clean. But when I do the export and bring it up in ShowTool, all of the normals are flipped so that its inside out.
Sometimes when I do the export, the mesh is translated far in front of the skeleton and I can see that the normals have been flipped. But this does not happen every time.
Just for a test I'm only attaching 2 bones to the Skin that I know are part of the animation to avoid the problems discussed in other threads.
I also re-did the bounding box from the top view per Evi's suggestion.
Has anyone seen this before?
I'm using Max8.
Thanks
Sometimes when I do the export, the mesh is translated far in front of the skeleton and I can see that the normals have been flipped. But this does not happen every time.
Just for a test I'm only attaching 2 bones to the Skin that I know are part of the animation to avoid the problems discussed in other threads.
I also re-did the bounding box from the top view per Evi's suggestion.
Has anyone seen this before?
I'm using Max8.
Thanks
About the author
#2
Easiest way to fix this problem is to add a normals modifier and unify (or flip if you choose) or perform the infamous box trick on your problem mesh.
Note: This problem occurs in pretty much all 3D applications and is not a Max or Max Exporter specific problem.
06/28/2006 (9:01 am)
There are a number of reasons for this. The most common cause is because you mirrored your mesh somewhere along the way, which in turn reversed the winding for the normals. The model will still display properly in Max but when it comes time to export the exporter reads the data as reversed and hence you get flipped normals.Easiest way to fix this problem is to add a normals modifier and unify (or flip if you choose) or perform the infamous box trick on your problem mesh.
Note: This problem occurs in pretty much all 3D applications and is not a Max or Max Exporter specific problem.
#3
06/28/2006 (9:22 am)
That makes a lot of sense. I did do the modelling my only doing half and then mirroring, welding. Your last note makes sense as well as I seem to remember reading about this problem in other game engines as well.
#4
My character's hair was normal-flipped in the showtool ? And I have never done the mirror to it ,Confusing......
06/30/2006 (1:52 am)
What about part of the model occur this problem?My character's hair was normal-flipped in the showtool ? And I have never done the mirror to it ,Confusing......
#5
06/30/2006 (2:32 am)
Is the hair using alpha? And are you sure it's "normal-flipped" and not just "not sorting right"?
#6
Maybe ,as you said , the normal is correct, I checked it up. The problem is in the map file . What does " sorting right " mean?
06/30/2006 (3:16 am)
Yes , I used png file in the diffuse and opaque channel , and opaque channel with alpha .Maybe ,as you said , the normal is correct, I checked it up. The problem is in the map file . What does " sorting right " mean?
#7
www.garagegames.com/index.php?sec=mg&mod=resource&page=category&qid=130#2050
06/30/2006 (7:13 pm)
Well , I found some tips about this . I'll try on my next workday.www.garagegames.com/index.php?sec=mg&mod=resource&page=category&qid=130#2050
#8
I typed " SORT::OL128 " in the cfg file , but dump file said , "Unknown bool parameter 'SORT::OL128' "
I change my character name to "SORT::OL128" in the max ,but cause max crashed when exporting.
:-(
07/02/2006 (8:27 pm)
All right , I read some tips about the " sorting" problem , but confused how ?I typed " SORT::OL128 " in the cfg file , but dump file said , "Unknown bool parameter 'SORT::OL128' "
I change my character name to "SORT::OL128" in the max ,but cause max crashed when exporting.
:-(
#9
07/02/2006 (8:31 pm)
You can't use SORT:: on skinned meshes, it will as you discovered, crash.
#10
07/02/2006 (8:42 pm)
Then , how can I sovle the sorting problem on skinned meshes?
#11
07/02/2006 (8:46 pm)
You cant.
#12
07/02/2006 (9:57 pm)
I detached the problematic part of the character , and export it as a static DTS . It is good in the showtool. Therefore ,both my model and maps don't have problems. 
Torque Owner Chuck Thomas