How to detach preserving normal orientation?

NAIMA

In 3dsmax, I havea surface I split into two bprdering parts to change the material type, mostly to change color more easily , but when I detach the normal maps get reoriented and instead I would like to preserve the normals in the same direction and united as it was a single mesh object, is it possible somehow?

Axi5

I haven't used Max in years but AFAIK you have to put an Edit Normal modifier on, click assign make explicit or something like that to lock the normals, then apply/collapse the modifier.

Edit:
https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/3DSMax/files/GUID-82722323-100B-4711-A01D-8A87EB53DD96-htm.html

NAIMA

Thats what I normally do , but in this case the objects sharing the border are split and two different meshes, I split but before splitting they shared the same normal , after split the normals at borders diverged, I would like to preserve the original normal orientation before splitting, is that possible?

gnoop

As Axi5  said if you make normals  explicit  before splitting your mesh  ,they should stay  same and  intact  after detaching .

if you want  to  fix it on already detached object  the only way I know is  Noors normal theft script  .     It can transfer normals from one object to another . 

Ghogiel

If the normals were averaged and didn't have any custom normals, you can average them manually on an already split mesh, you select both objects and add a edit normal to both then manually select pairs of the border verts and average selected, Recommended to not do that and just lock the normals before doing things that would break them, like detatching parts etc

Eric Chadwick

Why not use a Multi/Sub-Object material on a non-detached mesh, instead of detaching the meshes?

Ghogiel

Exporter might split the mesh and break the normals. That's why I've had to do this exact thing in the past at least. 

NAIMA

gnoop said:

As Axi5  said if you make normals  explicit  before splitting your mesh  ,they should stay  same and  intact  after detaching .

if you want  to  fix it on already detached object  the only way I know is  Noors normal theft script  .     It can transfer normals from one object to another . 

Sorry how do I do to make the normals explicit?

Axi5

Hi Naima,

Put the Edit Normal modifier on, select all the normals (I think ctrl+a works in Max I forget) they should all turn red AFAIK. Then click "make explicit" in the Edit Normal modifier. Check the documentation I posted if you're stuck.