Alembic Unable to import mesh due to a face consisting of 5 vertices。

General Feedback & Requests
1

alembic Unable to import mesh due to a face consisting of 5 vertices。 I always need octagonal faces or vertices to make some Houdini VFX, so I can’t use quadrangulate to triangulate the geometry. I just hope Unreal can support it like other DCC software.

2

This has been passed along to the team Janson :slight_smile:

3

any updates yet, I dont want VATs or any fancy stuff for some Houdini RBDs. I just want something quick for previs.

5

Hey updates on this? My teammate told me that all the faces are either 3 or quad verts but UE is still throwing up the ngons error.

6

This error occurs because the mesh you are trying to import into Unreal Engine contains some polygons with 5 vertices (pentagons). Unreal Engine only supports meshes with triangular (tris - 3 vertices) or quadrilateral (quads - 4 vertices) faces.

How to fix this in Houdini:

  1. Convert all faces to triangles or quads:
  • Use the Remesh or Convert SOP to convert all polygons into triangles or quads.
  • If you want to preserve the topology, try the Divide SOP with the “Triangulate Non-Convex” option.
  1. Check and fix pentagons (n-gons):
  • Use the PolyDoctor SOP to detect and automatically fix issues.
  • Use the Group SOP to select faces with more than 4 vertices, then apply PolySplit SOP or Triangulate SOP to subdivide them.
  1. Verify export settings:
  • When exporting to Alembic (.abc) or FBX, make sure to enable the “Triangulate Mesh” option.

Try checking your mesh in Houdini and re-exporting the file to see if the issue is resolved!