[dasssj]

Hi, guys.
I use SU2 for M6 optimization. The grid I use is download from (http://www.grc.nasa.gov/WWW/wind/val...1/m6wing.x.fmt). The FFD degree is (4,4,1) . I set the DV_VALUE to 1e-5 for one of the control point and set the others to zero,when I use SU2_DEF for grid deformation, it shows that there are 500 elements with negative volume . The mesh is good when I use SU2_CFD for direct computation.
The FFD box is attached below, the green line is the deformed box.
So how should I fix this problem?
Thanks!
Jason Shih