Compression Tool for Simulation Results


Simply compress efficiently: FEMZIP products are specialized for the compression of simulation results.

There are multiple versions suitable for various data formats common in the fields of crash simulation, NVH and CFD.


FEMZIP User Area




Press Release


Starting 01.01.2013 FEMZIP will be distributed and further developed by

Data Compression

In an effort to improve engineering design larger and more detailed models as well as an increasing number of simulations are performed, yielding a steady growing amount of data. This simulation data has to be analyzed, exchanged among engineers and archived for future reference and re-analysis. Network connections and storage space can then become bottlenecks in workflows used by engineers. The challenge is to handle these large amounts of data in a time- and storage-saving manner in order to eliminate the bottlenecks.

With our FEMZIP compression tools we provide a solution to meet this challenge. FEMZIP tools are specifically designed for the compression of simulation results of various simulation codes. The high compression factors that can be obtained by employing FEMZIP lead to several benefits:

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Reduced Archive Size
If all simulation data is compressed only a fraction of the storage is required. Storage and backup capacities can hold more simulation results. Hence, investments in the growth of storage and archive infrastructures can be avoided. 

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Shorter Data Transfer Times
Transferring result data across computer networks can be very time consuming. Transmission speeds are limited by the available network bandwidth. Since compressed simulation results require significantly less storage they can be transferred in a fraction of the time required for transferring uncompressed results.

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Quicker Data Loading
Reading data into post-processors can be a time consuming task as well. If data storage is provided on file servers, compressed data can be read directly into post processors significantly quicker due to the faster data transfer. In some cases load times can even be improved when reading from a local hard drive.

While providing these benefits FEMZIP is made to fit into the workflow used by engineers. It is designed to be integrated into batch processes to enable automated compression immediately after the simulation process. This way the engineer can benefit from data compression without the requirement of manually operating FEMZIP. Furthermore, on-the-fly decompression functionality of FEMZIP is integrated into common post-processing tools to make direct access to the content of compressed files possible. Hence, it is often not necessary to retrieve the original data formats with the stand-­alone decompression tool FEMUNZIP to view the compressed results.

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Crash simulation is a standard CAE application in the automotive industry. The effort of improving car safety is accompanied by large numbers of simulations performed on a daily basis. As a result vast amounts of simulation data are continuously produced. With FEMZIP for CRASH we offer a series of data compression solutions specially designed for commonly used crash-codes. FEMZIP versions are available for PAM-CRASH, LS-DYNA and RADIOSS result files.

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Test results by Volkswagen AG for PAM-CRASH output file (DSY) of a simulation using a car model with 1031990 nodes.

Typical crash result files can be reduced with FEMZIP by about a factor of 10. This reduction leads to considerably lower storage requirements, significant shorter data transmission and quicker data loading. The ladder can be experienced with a variety of post-processing tools that support the compressed data format of FEMZIP. To improve the experience of working with FEMZIP compressed files, we have worked together with post-processor developers to enhance the integration of our decompression technology. Today, a large number of post-processors support our format, so that working with compressed files has become easier than ever before.


Products: Supported post-Processors:
  • GNS Animator
  • ESI Visual Environment
  • LS-Prepost
  • Altair Hyperview / Hypergraph
  • Beta μETA
  • Oasys D3PLOT


The use of Computational Fluid Dynamics (CFD) in engineering applications generates tremendous amounts of data. We will be offering a set of newly developed FEMZIP data compression tools specialized for CFD data. The first data format to be supported will be CEI's EnSight Gold format. Further products for CD-Adapco's StarCD and the native OpenFOAM format are currently in development.

Usually, CFD results stored in the EnSight Gold format can be reduced by a factor between 5 and 10 depending on the simulation type. Output data from wind tunnel simulations can usually be compressed by a factor of over 5 for steady-state problems, whereas factors around 7-8 are achieved in the transient case.

Testergebnisse für instationäre Ergebnisse im EnSight Gold Format aus einer Windkanal Simulation mit einem Auto: 6 Variablen, 43 Millionen Elemente, 31 Zeitschritte
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Test results for EnSight Gold file of a transient airflow simulation around a car: 6 variables, 43 million elements, 31 time steps.

Because the scale that the output data of a single CFD simulation can reach, the performance and efficiency of the compression tools was a major concern during developement. FEMZIP-CFD products are built on a newly designed parallel software architecture to benefit from today‘s multi-core processors and enable fast compression and decompression.

Durchsatz-Benchmarks für single- und multi-threaded Läufe von FEMZIP-ENSG. Messungen wurden an einer 38GB EnSight Gold Datei durchgeführt. (Dual Intel Xeon CPU 2.93GHz quad-core Prozessoren, 24 GB RAM)
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Performance benchmarks for single- and multi-threaded runs of FEMZIP-ENSG. Benchmarks were performed on a 38GB EnSight Gold file. (Dual Intel Xeon CPU 2.93GHz quad-core processors, 24 GB RAM)
Products: supported post-processors:
  • FEMZIP-ENSG (EnsightGold)
  • FEMZIP-CCM (Star-CD)
  • EnSight


For Noise Vibration Harshness (NVH) analysis results are often calculated for a large number of modes. The emerging data of a single simulation usually comprises several GBs of data. For collaborating engineers at different sites that have to exchange this data across telecommunication networks data transfer can become a bottleneck in their workflows. Transfer times can be reduced significantly by employing FEMZIP. Instead of waiting for hours FEMZIP compressed NVH results can often be transferred in a matter of minutes. Consequently, a more fluent collaboration is possible. FEMZIP-N supports MSC NASTRAN and RASIOSS results stored in the OP2 data format.

Testergebnisse für eine Nastran OP2 Datei: Automodell mit 1428719 Knoten. Lösungs Typ 103, 51 Frequenzen
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Test results for Nastran OP2 file: Car model with 1428719 nodes. Solution Type 103, 51 modes.
Testergebnisse für eine Nastran OP2 Datei: Automodell mit 1026074 Knoten. Lösungstyp 101, 29 Frequenzen
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Test results for Radioss OP2 file: Car model with 1026074 nodes. Solution Type 101, 29 modes.

While very efficient compression is obtained for standard sized models, even larger compression factors are possible for results with hundreds or thousands of modes. In some cases it is possible to reduce result files by a factor of 40.

Products: supported post-processors:
    (NASTRAN / Radioss OP2)
  • GNS Animator
  • Beta μETA


FEMUNZIPFor all FEMZIP products the decompression is free of charge. This way our customers can benefit from FEMZIP data compression even when transmitting data to partners that have not licensed FEMZIP. FEMZIP compressed files can be opened from within various post-processors, making the decompression with FEMUNZIP redundant. For all other cases the current FEMUNZIP releases can be downloaded here.








FEMZIP-CFD products have not been released.