FBX lost custom vertex normals after import to 3dsMax #57673

New Issue

Jan Javůrek · 2018-11-07T10:47:32+01:00

Jan Javůrek commented

2018-11-07 10:47:32 +01:00

System Information system-info.txt
Win 10 Home and graphics card Geforce 970

Blender Version
Broken: 2.79, hash: 5bd8ac9; 2.80. Alpha 2, hash: b4dfe00fd6
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.fbx

Blender

3dsMax

Exact steps for others to reproduce the error

create a cube
make a bevel to all edges
set Auto Smooth ON in Object data and set the Angle to 180
select all faces in edit mode and press mesh/shading/smooth faces
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
export the cube as FBX with Write Edge/Face smoothng in Geometry-related setting (check Tangent is not helping)
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
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

**System Information** [system-info.txt](https://archive.blender.org/developer/F5413029/system-info.txt) 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.fbx](https://archive.blender.org/developer/F5422951/box_to_max.fbx) ![image.png](https://archive.blender.org/developer/F5421823/image.png) Blender ![image.png](https://archive.blender.org/developer/F5421859/image.png) 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 8. 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

Jan Javůrek commented

2018-11-07 10:47:32 +01:00

Added subscriber: @skywalger

Jan Javůrek commented

2018-11-07 14:05:26 +01:00

Added subscriber: @brecht

Jan Javůrek commented

2018-11-07 14:05:26 +01:00

@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.

Bastien Montagne was assigned by Brecht Van Lommel

2018-11-07 14:19:09 +01:00

Brecht Van Lommel commented

2018-11-07 14:19:09 +01:00

Added subscriber: @mont29

Brecht Van Lommel commented

2018-11-07 14:19:09 +01:00

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

Bastien Montagne commented

2018-11-07 14:25:46 +01:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2018-11-07 14:25:46 +01:00

Bastien Montagne commented

2018-11-07 14:25:46 +01:00

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.

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 commented

2018-11-07 15:52:03 +01:00

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

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FBX lost custom vertex normals after import to 3dsMax #57673