Reno Genest
Ansys Employee


It looks like you are doing an implicit simulation. AUTOSPC constraints are added to an implicit model to prevent rigid body motion which is not allowed in implicit. Here is what you can try:

  1. Fully constrain the parts in your model so that they don't move as a rigid body. Then run the implicit model again.
  2. Do an explicit simulation. It is okay to have rigid body motion in an explicit simulation.

Also, the error message recommends to switch to REAL 8 version of LS-DYNA. This means using a double precision solver. You can download one here:

LSDYNA » Downloader (

username: user

password: computer


If you are new the LS-DYNA, it would be good to go through some training. Do you have access to the Ansys Learning Hub (ALH)?

You will find the WB LS-DYNA course here:

And many LS-DYNA courses here: