geometryFromMesh : All elements in the mesh must have positive volume.

Hi, I am trying to use the geometryFromMesh to import the geometry and mesh created by delaunayn in matlab. I have checked for coplanarity and other "bugs" and everything seems fine. There are some positive nodes and some negative nodes in the mesh. For those nodes that have negative values, the volume can be negative. So, I don't understand why this error message keeps showing up: ******************************************************************************************************** All elements in the mesh must have positive volume. The problem may be bad elements or an element numbering convention that differs from MATLAB. ********************************************************************************************************* Any suggestions? Thanks. Best wishes, Souvik