Name of the file with the initial material distribution field to be used for the optimization.
Remarks
All elements in the element group might be modified during optimization.
Only certain types of elements (for more information, see Tosca Structure User Guide) are permitted to be optimization elements. All elements not permitted
are removed from the group.
The INITIAL_DV_FIELD option is available only for sensitivity-based
optimization.
The file applied at INITIAL_DV_FIELD containing the initial material
distribution must be located in the start directory of the optimization job. The format of the file must be ONF (Optimization
Neutral File). The initial material distribution is extracted from the data block 740 with
the title MAT_PROP_NORMALIZED.
When using a material distribution of a previous optimization run for the new optimization,
rename the file TP_XXX.onf (for example, to INITIAL_MAT.onf).
Otherwise, name conflicts with the running optimization (with newly generated
material distribution files TP_YYY.onf) might lead to confusion in the post
processing: the start file TP_XXX.onf might be considered and shown as the last
iteration (if XXX is larger as the last iteration in the actual optimization).
(For more information, see Use Results from Previous Runs as Initial Material Distribution).
The former parameter RESTART_FILE was renamed to INITIAL_DV_FIELD to avoid confusion with the restart of unintentionally stopped optimization runs
(see Restart and Resume Modes).
INITIAL_DV_FIELD for topology optimization means an initial material distribution for design variables.