Realflow Alembic mesh smoothing.
Open, NormalPublic

Description

Dear Kévin,

it's nice to see how smooth realflow meshes are working in Blender with alembic.
I ran into a weird problem... My smoothing on the mesh isn't working.

I tried everything I know about smoothing and normals... maybe I'm doing something wrong, or its broken somehow.
I marked it as a bug but it could also not be a bug.

  • I push smooth shade button.
  • Autosmooth is disabled
  • I checked custom split normal data, there is none.
  • I tried with Autosmooth on and different angles
  • No succes.
  • Also tried sub-d modifier and edgesplit and some combinations, but it stays flat shaded.

Here is the mesh sequence in alembic format.

WIN 7 64b B27.8a

Thx for looking into this.

Regards,

Minne

Details

Type
Bug

The issue probably comes from the fact that meshes are empty when importing Alembic objects and the data is generated by the modifier. For smooth normals to be applied through the modifier, it needs to be applied on the mesh before it gets fed through the modifier stack, but since meshes are empty before going through the modifiers, the smooth normal data can not be carried.

As a temporary solution, you could try to create a dummy object (like a cube), and add the Mesh Sequence Cache modifier to it, properly setting the cache file and the object path. Then smooth normals should work.

Normals in Alembic are a bit of a hassle since they can be stored in different ways, and it is not as straightforward to handle them on the Blender side as it seems (a lot depends on how other software output their normal data). Perhaps I could add a user setting to the modifier to tell to set smooth normals flag on the mesh's polygons?

In any case, I had to reinstall my OS, and I haven't yet reinstalled the Blender related stuff, let alone the compilers and general development stuff, so this will have to wait a bit before I can take action.

Thx for the clear explanation and more importantly: a working solution!

It would be nice to have the option flag for sure.

What about this : Importing the sequence with a mesh that is not empty? I'm guessing 1 triangle would do the trick.
When you create the "dummy mesh" you could add 1 triangle(or wathever is needed) before adding the modifier.
Dono if such a solution is acceptable design wise...

In any case thx again for the fast response and the "good enough for me" solution. :)

Bastien Montagne (mont29) triaged this task as Normal priority.Dec 16 2016, 6:10 PM