Not gatting solution

Pranav6111

In HyperMesh 2026 (OptiStruct user profile), my OptiStruct job completes immediately after the header with no analysis/iterations — .out file only shows startup info + empty "Iteration Subcase Variable Grid/Elem ID Value" table. No subcase processing or results.

Model Browser shows:

• Load Step Inputs (1)
• SUBCASE (2) under some branch
• But no proper "Loadsteps" entity or Load Step collector that defines SPC + LOAD.

Loads: FORCE (3), SPC (4), ~73k elements, bike frame model with topology opt likely.

When I export .fem, no SUBCASE card appears (or it's invalid/empty). Job runs in seconds → "Job completed" but nothing happens.

What am I missing? How do I create the actual Load Step entity in HM 2026 so SUBCASE gets exported correctly with SPC= and LOAD= references?

erdem.keskin

It sounds like your model does not contain a valid Load Step (SUBCASE) entity, even though you have FORCE and SPC defined.

In OptiStruct, defining loads and constraints alone is not sufficient. They must be referenced inside a proper SUBCASE. If no valid SUBCASE exists in the exported .fem, the solver reads the model, finds no active load case, prints the header + empty iteration table, and exits immediately. That’s why your job finishes in a few seconds with no results.

From your description:

• You have FORCE entities
• You have SPC entities
• Model Browser shows something under “Load Step Inputs”
• But no real Load Step entity linking SPC= and LOAD=

That is the issue.

What you need to do

1. In Model Browser, right-click → Create → Load Step
2. Set:
   • Analysis Type → Static (or Optimization if applicable)
   • SPC → select your SPC collector
   • LOAD → select a LOAD collector

Important:

• FORCE is not the same as LOAD.
• You must create a LOAD collector (Card Image = LOAD) that references your FORCE entries.
• Then assign that LOAD collector inside the Load Step.

After export, your .fem file must contain something like:

SUBCASE 1  SPC = 4  LOAD = 3

If this block does not appear, the solver has nothing to solve.

For topology optimization, you also need DESVAR/DRESP/DCONSTR etc., but even then, OptiStruct will not start without a valid SUBCASE.

So the root cause is:
No valid Load Step → No SUBCASE in .fem → Solver exits immediately.