hello ... how large is your time step?can you show the mesh?

nHello, my time step size is 0.0005s and I have the error from the beginning. So basically when I try to run the 'Preview Mesh Motion' to see if my udf is doing what it is supposed to do, I directly receive the message and it's impossible to update the mesh. The mesh I am using has 1milion-ish tetrahedrons