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Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
Engine Input
This manual provides a list of all the solution definition keywords and options available in Radioss.
Animation and Post-processing Output Files
Generates animation files containing results according to the keywords specified. The keywords are specified in the topics within Animation and Post-processing Output Files.
H3D Output
/H3D/PART
Engine Keyword Define which parts will be saved in the H3D file. The H3D file will only contain the model and result data for the listed part_ID_s.

Welcome
What's New
View new features for Radioss 2025.1.
Overview
Radioss^® is a leading explicit finite element solver for crash and impact simulation.
Tutorials
Discover Radioss functionality with interactive tutorials.
User Guide
This manual provides details on the features, functionality, and simulation methods available in Altair Radioss.
Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
- File Extensions and Formats
  Current Radioss format uses the 12x extension format.
- Single File Input
  This format allows running either Starter or Engine with the same file.
- New Keywords in 2025
  New and modified features in Radioss.
- Starter Input
  This manual provides a list of all the model definition keywords and options available in Radioss.
- Engine Input
  This manual provides a list of all the solution definition keywords and options available in Radioss.
  - Engine Keywords Syntax
  - General Controls
    Engine Keyword In this group keywords are used to generally define the output style, control of computation, damping and ALE setup during the computation.
  - Deletion/Input Modifications
    Engine Keyword In this group, keywords are used for modification (deletion or add options) in Engine.
  - Animation and Post-processing Output Files
    Generates animation files containing results according to the keywords specified. The keywords are specified in the topics within Animation and Post-processing Output Files.
    - Nodal Animations
    - Element Animations
    - Brick Animations
    - Shell Animations
    - Other Animations
    - Curve Plots
      Engine Keyword
    - H3D Output
      - /H3D/BEAM
        Engine Keyword Generate H3D contour output results for /BEAM beam elements.
      - /H3D/COMPRESS
        Engine Keyword Compress the H3D file.
      - /H3D/DT
        Engine Keyword Writes the H3D results file at specified output frequency.
      - /H3D/LSENSOR
        Engine Keyword Write additional animation time steps to the H3D file when a sensor in the list is activated.
      - /H3D/NODA
        Engine Keyword Generate H3D contour output results for nodes.
      - /H3D/PART
        Engine Keyword Define which parts will be saved in the H3D file. The H3D file will only contain the model and result data for the listed part_ID_s.
      - /H3D/RBE2/SINGLE_PART
        Engine Keyword Display all RBE2 in a single part.
      - /H3D/RBE3/SINGLE_PART
        Engine Keyword Display all RBE3 in a single part.
      - /H3D/RBODY/SINGLE_PART
        Engine Keyword Display all rigid bodies (/RBODY) in a single part.
      - /H3D/QUAD
        Engine Keyword Generate H3D contour output results for /QUAD quad elements.
      - /H3D/SHELL
        Engine Keyword Generate H3D contour output results for /SHELL and /SH3N shell elements.
      - /H3D/SOLID
        Engine Keyword Generate H3D contour output results for /BRICK, /BRIC20, /TETRA4, /TETRA10 solid elements and /BRICK, /PENTA6, /SHEL16 thick shells.
      - /H3D/SPH
        Engine Keyword Generate H3D contour output results for SPH.
      - /H3D/SPRING
        Engine Keyword Generate H3D contour output results for /SPRING spring elements.
      - /H3D/TITLE
        Engine Keyword Write additional name description to the H3D file content.
      - /H3D/TRUSS
        Engine Keyword Generate H3D contour output results for /TRUSS truss elements.
    - Other Output Files
      Engine Keyword
  - Implicit Solution
    Engine Keyword In this group keywords are used for implicit solution. Different implicit solver methods (linear, nonlinear, buckling or quasi-static), different options to control the implicit computation, different implicit time step method and implicit output messages are introduced.
  - Kinematics and Loading
    Engine Keyword In this group, keywords are used to define the kinematic condition (constrain/release rotation or translation DOF) and initial condition (rotational/translational velocity).
  - Time Step
    Engine Keyword In this group, keywords are used to define different time step control (STOP, KILL, CST or DEL, and so on) for different entities (shell, brick, beam, airbag, interface, and so on) during the computation.
  - Initial State
    Engine Keyword In this group, keywords are used to output different info (like stress, strain, orthotropy direction, temperature, and so on) in a state file (STA-File).
- LS-DYNA Input
  This manual provides a list of LS-DYNA input files available in Radioss.
- Multi-Domain
  This manual contains the description of the keywords for the Radioss Multi-Domain.
- Obsolete Keywords
  Keywords that are still supported, but no longer maintained (*) are considered obsolete.
- Other Files
- Definition
Example Guide
This manual presents examples solved using Radioss with regard to common problem types.
Verification Problems
This manual presents solved verification models.
Frequently Asked Questions
This section provides quick responses to typical and frequently asked questions regarding Radioss.
Theory Manual
This manual provides detailed information about the theory used in the Altair Radioss Solver.
User Subroutines
This manual describes the interface between Altair Radioss and user subroutines.

/H3D/PART

Engine Keyword Define which parts will be saved in the H3D file. The H3D file will only contain the model and result data for the listed part_ID_s.

Format

/H3D/PART

part_ID₁... part_ID_N

Definition


Field	Contents	SI Unit Example
`part_ID`₁...`part_ID`_N	The H3D file will only contain the model and result data for the listed `part_ID`s.

Example

The h3d file will only contain model and result data for part_ID_s=356, 293, 476, 489, 256

/H3D/PART
356 293 476 489 256