Fix T79700: skin modifier: prevent error for vert-only mesh

Vert-only mesh is valid input for the skin modifier (displays isolated
cubes), prevent error message about missing root vertex in that case.

Maniphest Tasks: T79700

Differential Revision: https://developer.blender.org/D8533

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/modifiers/intern/MOD_skin.c b/source/blender/modifiers/intern/MOD_skin.c
index 8f0174fe6d9..228cd4cc4ae 100644
--- a/source/blender/modifiers/intern/MOD_skin.c
+++ b/source/blender/modifiers/intern/MOD_skin.c
@@ -773,6 +773,11 @@ static EMat *build_edge_mats(const MVertSkin *vs,
 
         *has_valid_root = true;
       }
+      else if (totedge == 0) {
+        /* Vertex-only mesh is valid, mark valid root as well (will display error otherwise). */
+        *has_valid_root = true;
+        break;
+      }
     }
   }