1) sometimes while using the design tool in adjoint solver, while modifying the mesh after calculating the Design Change, an error might be reported for negative cell volume. 2) this means that while morphing, a bad quality mesh was created leading to negative cell volumes. 3) in such cases, the prior mesh can be achieved using the Revert Mesh option as shown in the image attached herewith. 4) However, it is recommended to use the Preview mesh prior to actually morphing to get an idea about the mesh subsequent to the morphing operation. 5) The negative cell volume can be due to bad quality mesh in base model itself, poorly converged adjoint solution or very high objective functions.

Attachments:
1. adjoint_revert_mesh.jpg