# Performance Issue When Importing Large .inp File with STEP Command **URL:** \ **Category:** Bug Reports\ **Created:** [August 4, 2025, 9:27pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908 "2025-08-04T21:27:13Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 4, 2025, 9:27pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/1 "2025-08-04T21:27:13Z")
Dear PrePoMax team, I’m experiencing a performance issue when importing a large `.inp` file (around 100,000 elements). PrePoMax reads the file correctly, but the import takes a very long time **only when the `*STEP` section is included**. If I remove the `*STEP` part, the file loads quickly. Here is a link to the `.inp` file for reference: > **[mesh\_output\_single.zip](https://drive.google.com/file/d/1AWaMCmtK9NEXnaWfi3V-SdLXfbPcjAN0/view?usp=sharing)** > > Google Drive file. Thank you for the great software and support! ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [August 5, 2025, 7:26am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/2 "2025-08-05T07:26:06Z")
The problem is the number of \*Equation keywords. They are converted to individual user keywords, which must be correctly indexed into the model-generated keywords, and this causes a big problem. I will have to add grouping of similar keywords to the inp reader so that all \*Equation keywords would be recognized as one. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [August 5, 2025, 7:37am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/3 "2025-08-05T07:37:33Z")
If you have a script to prepare the \*Equation keywords, you can try to define all the keywords under one \*Equation keyword as: > \*EQUATION > 3 > 120945,2,1, 40143,2,-1, 121206,2,-1 > 3 > 120945,3,1, 40143,3,-1, 121206,3,-1 instead of: > \*EQUATION > 3 > 120945,2,1, 40143,2,-1, 121206,2,-1 > \*EQUATION > 3 > 120945,3,1, 40143,3,-1, 121206,3,-1 Calculix can read such an entry, but I did not check the results to see if it really works. ---
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 5, 2025, 8:00am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/4 "2025-08-05T08:00:31Z")
Thanks Matej for you fast answer, I didnt know that, I’ll try it and let you know. ---
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 5, 2025, 8:13am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/5 "2025-08-05T08:13:37Z")
Unfortunately, that didn’t work. I remember trying to use a single \*EQUATION keyword, but CalculiX didn’t read it properly, which is why I had to apply the keyword to each node separately. As for PrePoMax, the issue persists. Here is a link to the modified .inp file with a single \*EQUATION keyword. > **[mesh\_output\_vf60\_r0.02\_100x100.inp.zip](https://drive.google.com/file/d/1KxfRZqlaXjVmvMDeedRr52JFnKe9p8Tt/view?usp=sharing)** > > Google Drive file. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [August 5, 2025, 11:30am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/6 "2025-08-05T11:30:57Z")
Ok, I fixed some additional bottlenecks. The fix will be available in the next version. It will definitely work for a single \*Equation keyword with multiple equations. I will try to add default keyword grouping, but I am not sure it will make it in the next version. ---
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 5, 2025, 2:58pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/7 "2025-08-05T14:58:01Z")
Ok, so i fixed some things in my script and it indeed worked in ccx with just one \*equation command as you suggested. As with prepomax it’s the same. It’s not an issue since i can just run calculix outside and use prepomax for postprocessing only. Thanks! ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [August 6, 2025, 12:42pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/8 "2025-08-06T12:42:10Z")
I added some additional fixes so that now it will work much faster for a single or multiple keywords. ---
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 6, 2025, 1:28pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/9 "2025-08-06T13:28:44Z")
Thanks a lot! I there a way to download a nightly build exe of prepromax? I am currently using 2.3.7 dev and I couldnt fine a release version on gitlab. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [August 6, 2025, 3:05pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/10 "2025-08-06T15:05:26Z")
Try compiling with this script: [CMD-script for automatic PrePoMax compilation](https://prepomax.discourse.group/t/cmd-script-for-automatic-prepomax-compilation/463/1) ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [August 7, 2025, 11:26am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/11 "2025-08-07T11:26:14Z")
> [@Mesab](#): > > Thanks a lot! > I there a way to download a nightly build exe of prepromax? I am currently using 2.3.7 dev and I couldnt fine a release version on gitlab. No, but I will probably create a new developer release in a day or two. ---
**Author:** ![Mesab](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mesab](https://prepomax.discourse.group/u/Mesab)\ **Post date:** [August 12, 2025, 12:32pm UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/12 "2025-08-12T12:32:59Z")
The new version works perfectly 👍 ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [September 9, 2025, 6:27am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/13 "2025-09-09T06:27:12Z")
I am closing this topic. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [September 9, 2025, 6:27am UTC](https://prepomax.discourse.group/t/performance-issue-when-importing-large-inp-file-with-step-command/2908/14 "2025-09-09T06:27:14Z")