Maniphest T57673

FBX lost custom vertex normals after import to 3dsMax
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Assigned To
Bastien Montagne (mont29)
Authored By
Jan Javůrek (skywalger)
Nov 7 2018, 10:47 AM
Tags
  • BF Blender
  • BF Blender: 2.8
  • Import/Export
Subscribers
Bastien Montagne (mont29)
Brecht Van Lommel (brecht)
Jan Javůrek (skywalger)

Description

System Information

system-info.txt24 KBDownload

Win 10 Home and graphics card Geforce 970

Blender Version
Broken: 2.79, hash: 5bd8ac9; 2.80. Alpha 2, hash: b4dfe00fd60
Worked: none I think

Short description of error
FBX exported from both Blender 2.79 and 2.8 Alpha 2 into 3dsMax 2016+ do not preserve custom vertex normals

box_to_max.fbx12 KBDownload

Blender

3dsMax

Exact steps for others to reproduce the error

  1. create a cube
  2. make a bevel to all edges
  3. set Auto Smooth ON in Object data and set the Angle to 180
  4. select all faces in edit mode and press mesh/shading/smooth faces
  5. select some edges and mark them as sharp, in 2.79 via Set normals From Face; in 2.8 via Mesh/Normals/Set From Faces
  6. export the cube as FBX with Write Edge/Face smoothng in Geometry-related setting (check Tangent is not helping)
  7. import the FBX into 3dsMax 2016+, in import settings, check Smoothing groups in Geometry tab

note: importing the mesh without checked smoothing groups results in seemingly correct vertex normals and smoothnig, but reality is that the mesh has all edges as hard/flat now, the normals are just locked in correct directions (try Edit normals/reset to see it), thus there are much more vertex normals than is needed

  1. observe bad shading of the model (custom vertex normals are gone)

I guess that the 3dsMax can't read the custom vertex normal and hard/soft edges correctly from the Blender FBX. The question is, what needs to be fixed? Blender exporter or Max importer?

This might be related to this bug report https://developer.blender.org/T57663

Related Objects

Event Timeline

Jan Javůrek (skywalger) created this task.Nov 7 2018, 10:47 AM
Jan Javůrek (skywalger) updated the task description.Nov 7 2018, 1:55 PM
Jan Javůrek (skywalger) added a project: Import/Export.Nov 7 2018, 1:59 PM
Jan Javůrek (skywalger) added a subscriber: Brecht Van Lommel (brecht).EditedNov 7 2018, 2:05 PM

@Brecht Van Lommel (brecht) can you look into this bug pls? You have been helpful in answering similar issue https://developer.blender.org/T57663 Probably it will be again mistake on side of 3dsMax...I just wanna be sure. Thank you.

Brecht Van Lommel (brecht) assigned this task to Bastien Montagne (mont29).Nov 7 2018, 2:19 PM
Brecht Van Lommel (brecht) lowered the priority of this task from 90 to Normal.
Brecht Van Lommel (brecht) added a subscriber: Bastien Montagne (mont29).

This is one for @Bastien Montagne (mont29), I don't know how custom normals work in FBX.

Bastien Montagne (mont29) changed the task status from Unknown Status to Unknown Status.Nov 7 2018, 2:25 PM

Nobody officially knows anything about FBX, since there are no public specifications… even worse when it comes to 3DSMax and Maya, as those add their own 'FBX flavor' through custom namespaced data.

Bottom line: afaik custom normals are correctly exported from Blender (FBX has direct support for such data). What Max does with them is not really in our realm of knowledge and action. So am afraid answer will be the same as with smooth groups: that is probably something wrong on 3DSMax side, we cannot do much about it.

Jan Javůrek (skywalger) added a comment.Nov 7 2018, 3:52 PM

Thank you for explanation...I will go bother Autodesk so they fix their software...wish me good luck :D

Alan Mattano (AlanMattano) mentioned this in T66537: Exporting FBX loos vertex normal out from original imported FBX file as an example..Jul 7 2019, 9:35 PM