STEP file causing crash

[anirudhnehra]

Hello, I aqm trying to import a step file rather big(268 MB) but freecad(this version or stable) crashes on opening it. Here is the link to step file:https://drive.google.com/file/d/1rkjPUH4aPEhQMZN0M71iWt4Sfywc-QR3/view?usp=sharing

Also, I could not find preferences for STEP under IMPORT section of preferences. Please take a look.

Thanks and Regards Anirudh Nehra

[luzpaz]

Please refrain from ALL CAPSing ticket titles. Remember to always copy/paste your full About info.

[anirudhnehra]

OK. Please see below. OS: Linux Mint 20.2 (XFCE/xfce) Word size of OS: 64-bit Word size of FreeCAD: 64-bit Version: 2021.922.24301 +4188 (Git) AppImage Build type: Release Branch: LinkDaily Hash: 3de879c7a2ba7111cc769d98636eb6d43189459d Python version: 3.9.7 Qt version: 5.12.9 Coin version: 4.0.1 OCC version: 7.5.2 Locale: English/India (en_IN)

Thanks and Regards Anirudh

[realthunder]

It's an OCCT bug, and has a simple fix. I'll submit a PR to them later. Can I use your file as a sample when reporting the problem?

[realthunder]

Just checked that OCCT has fixed this problem in 7.6, which hasn't been released yet. Looks like we'll have to patch it by ourselves somehow.

[anirudhnehra]

Yes sure you can use it. Also, could you fix that memory leak problem of freecad. Freecad doesn't release the memory occupied by it when we create a rather big array of a part and then delete the array.

Regards Anirudh Nehra

[realthunder]

I don't think that is memory leak. The deleted object will normally stay in the undo stack, and the undo stack has a predefined maximum length.

[anirudhnehra]

OK might be. But the screen capture I sent to you definitely showed that after creating a big array freecad occupied quite a bit of RAM, but closing the document then did not free up the RAM. I share link. https://drive.google.com/file/d/1TH1Gelmr6s7I4Q2rrlNMZiHgXGAWGB4n/view?usp=drivesdk

Regards Anirudh

[realthunder]

Are you using the upstream FreeCAD in the screen capture? Please try with my Daily branch, and use the recommended STEP export setting below. The highlighted settings are most relevant for large complex models.

You probably also want to enable the experimental renderer for better rendering performance, Tools -> Preset configurations -> Display settings. Note that there is some deficiency when using the transform tools in experimental render. I have just fixed that. It will not cause too much slow down when transforming in future release.

I have tried 100 instances with around 4GB memory usage. After applied transformation to one of the segment, the memory usage went up to 7GB, which I have already explained is due to recomputation pushes old shapes to undo stack. But that's only one of the reasons. You can't really tell how much memory the application is actually using relying solely on some type of external resource monitor. The system memory allocator may keep the allocated pages even the application has freed it, and only truly release the page when the kernel demands it because other application requires it. To prove this, you can close the document and open it again, perform the same transformation operation, and you'll find that FreeCAD memory usage stays about the same.

[anirudhnehra]

Hi, 1-Yes I am using the daily branch of your ASM3 version. 2-I am using the experimental renderer and yes it slows down a bit on using transform tool. 3-Is there a way to disable undo/redo feature which might be causing increased memory usage. 4-Maybe the system monitor is reporting incorrect value but the observed fact is: when the system monitor shows close to 100 percent RAM usage(for example my system has 32 GB RAM and at around 31 GB occupied), the computer starts to hang up and the screen freezes. Opening and using any other application is not possible. 5-Yes I am using the same settings as shown by you. It still crashes. 6-Also, creating the array operation( say 400 by 400) and not using transform tool if I remember correctly increases RAM usage. the issue is I create the array and freecad takes more RAM. But when I close the "same document" but not freecad, the RAM usage is still the same(high). It should come down with the closure I guess.

I have one other query. Is it possible to embed a macro script in the model tree? For example I write a macro that calculates mass before applying a fillet. I need this macro to always run before fillet is recomputed so that the mass of a body without filleting is reported. Is it possible make macro as a feature in model tree?

Regards and Thanks Anirudh Nehra

[realthunder]

The key to keep memory usage in check is to not building any compound shape with array. Even if OCCT compound is relatively cheap, it still occupies memory, and much more noticeable with array of complex model. Please make sure you are using the STEP import setting I posted above which avoid using any compound. And with the new 10.15 release, when creating draft array, you have the option to disable Build shape. You can also do the same with existing array using the context menu (right click the array icon in the tree view, and Disable build shape). In case you want to move an array element (not draft array, but link array imported from STEP), right click the array, and select Toggle array elements.

About the macro, how do you intend to report the mass? In my branch, you can write expression to do pretty much anything macro can do.

[anirudhnehra]

Hi, Ok I will try your setting. Infact I tried and it doesn't work still. -One improvement in path array tool could be pattern by chordal length(straight distance between consecutive elements on the curve rather than distance along the curve) .This tool will be very helpful to build chains of cycles or excavator /cable tracks. Please see this video for more details. It simulates realistic chain https://youtu.be/KrEIHjZ3Qgs

-Another improvement could be pattern by reference. That means suppose I build array of coordinate systems on a path. Then I make a body and want body to be coincident in position and orientation with each corresponding member of array of CSYS. I could then use attachment constraint of ASM3 and locate first body with the seed member of CSYS array. Then I just say array on the body and all bodies are created (equal to number of CSYS) and oriented automatically to match the coordinate system array . This feature of reference array is available in every major cad software. It also helps to reduce memory footprint. Please see this series https://youtu.be/-R9myIG5XjA I think Creo Parametric has the best pattern tools worth taking a look at.

-Regarding the macro, it could report anywhere. It could write to a CSV file or in report view or create a model tree feature. The main issue is fixing the timestamp at which this macro must be executed using CTRL+R. It must allow to be executed after a feature of choice in the model tree. -Also, one more improvement could be feature suppression by variable using a spreadsheet.(0 could be feature off and 1 feature on). -One other improvement could be in sketcher- "Perimeter Dimension". Suppose I have a connected chain of lines/arcs/bsplines in sketch whose Overall length I want to be constant.(Thus overall length is same as perimeter). Then I dimension length of all elements in the sketch except one whose length I want ot be driven by (perimeter dimension-length of all other chain). Maybe It could be done in expressions but we don't have a tool to retrieve length of selected elements in a sketch. -ARC/bspline length dimension in sketcher can be a good enhancement too. Though freecad is great, we could always learn something from other software. Freecad has to become primarily a mechanical design tool and I hope it reaches the same capabilities as the big three(Creo, NX, Catia)

I am also finding it difficult to understand how ASM3 opens STEP files, especially the subassemblies. All subassemblies or arrays(say of a circular array of bolts) are represented as linked parts. If I hide the subassembly link, the bolts inside the assembly are hidden too even if I unhide them. The linked subassemblies are linked to somewhere which is difficult to find. How does freecad Asm3 determine what is to be a linked part/subassembly and what is a solid part during import. Because when the same step is exported through Solidworks etc. , every object in the model tree is a solid part. Is there any documentation related to this?

Regards and Thanks and keep up the good work. Anirudh Nehra

EDIT:I just loaded the STEP in the latest release and it works without problem. However, rendering seems a bit slow. (OS: Linux Mint 20.2 (XFCE/xfce) Word size of OS: 64-bit Word size of FreeCAD: 64-bit Version: 2021.1015.24301 +4280 (Git) AppImage Build type: Release Branch: LinkDaily Hash: 556c87868ea46796242156e9f73eae98259794b7 Python version: 3.9.7 Qt version: 5.12.9 Coin version: 4.0.1 OCC version: 7.5.2 Locale: English/India (en_IN)

[anirudhnehra]

Hi, Please also include "split edge" tool in sketcher in future releases of ASM3. It is available in weekly build of freecad. This version: (OS: Linux Mint 20.2 (XFCE/xfce) Word size of FreeCAD: 64-bit Version: 0.20.26202 (Git) AppImage Build type: Release Branch: master Hash: ca6d49d080dea0abc23d954743eca7c46f33469b Python version: 3.9.7 Qt version: 5.12.9 Coin version: 4.0.0 OCC version: 7.5.3 Locale: English/India (en_IN)

And please make it to snap to existing vertex(end of line)

Thanks Anirudh