STEP 3D export exports the incorrect files

[Willem Hillier]

Application: kicad
Version: (5.0.2)-1, release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.61.1 OpenSSL/1.1.1 (WinSSL) zlib/1.2.11 brotli/1.0.6 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.5) nghttp2/1.34.0
Platform: Windows 8 (build 9200), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8)
    Boost: 1.68.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.61.1
    Compiler: GCC 8.2.0 with C++ ABI 1013

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON

I'm running on Windows 10 64-bit

Often, KiCad's exported STEP model for a board simply does not match what is shown in the 3D viewer. Either, the correct sub-part (3d model for a component) is present, but it is rotated or placed incorrectly, and/or an entirely incorrect part is imported when the STEP file is loaded into SolidWorks or Fusion360 (I have not tried other MCAD packages, but since the issue is present upon STEP import in both these packages, I think it is fair to assume the issue lies with KiCad and not my MCAD packages). This happens with both custom parts that I have assigned STEP file(s) to, as well as some built-in packages.

An example of a board where I'm having this issue is here: https://github.com/willemcvu/AERO-Boards-KiCad/tree/master/interface-board-standoffs

On that board, some examples of components that do not export correctly include RV1, U2, U5, and others.

Also my apologies, the paths for the 3D models will need to be remapped somewhere other than my home folder (I need to set up aliases properly) in order for anyone else to see 3D. All the 3D models that my file references are found here: https://github.com/willemcvu/AERO-Boards-KiCad/tree/master/3d_models

Steps to reproduce:

1. Export step from KiCad.
2. Import into SolidWorks or Fusion 360.
3. Notice that some components have broken 3D models.

Let me know any other info that might be needed; this is my first KiCad bug report.

[Nick Østergaard (nickoe)]

Do you have wrl models of your step files? Maybe those are used for the 3d viewer?

[Willem Hillier (willemhillier)]

I don't have WRL models, and I am very sure that KiCad is using STEP files (which I have for all my 3D models) to build the 3D model of the whole board for STEP export.

[Seth Hillbrand (sethh)]

@Nick- Can you add some details about why you feel this isn't the same as the lp:1784257

[Nick Østergaard (nickoe)]

@Seth, I removed it as a duplicate again. I suspected ot was an issue wit an outdated wrl model. IIRC the 3d viewer silently uses wrl models if it is named the same as a step model to better support kicad stepup. But the other issue memtioned that there were no wrl models, so I removed it as a duplicate.

[Seth Hillbrand (sethh)]

Ok but lp:1784257 is the STEP issue. If there's something distinct that you'd like addressed in 5.1.1, can you add the specific details?

[Nick Østergaard (nickoe)]

I mostly assigned it 5.1.1 as I wanted to review the issue when I get home, and I conso
Ider bugs where people are kind enough to add example files more urgent. The reporter did link a test project in this case.

[Willem Hillier (willemhillier)]

lp:1784257 seems to do with scale/shift. I'm seeing that issue (shifting, not scaling) here, but I'm also seeing KiCad just blatantly assign incorrect STEP models. For example, on my test project, I have a separate bolt-on module for my DC/DC converter module. That module exports to a STEP fine, but then when I add it as a 3D file to the footprint for it in the larger project (the board it mounts to), it displays fine in the 3D viewer but gets exchanged for other parts when exporting a STEP file of the whole project. This is actually a significant issue for me as I'm designing this board as part of a larger mechanical assembly, and I'm seeing it happen with the big connector, and the DC/DC module - the two most important parts in the context of a mechanical assembly. Right now as a work-around I'm importing those parts into MCAD as separate components and mating them.

Like I said, I'm not involved in the KiCad project myself, but this issue can have pretty big consequences in terms of MCAD integration with KiCad.

[Seth Hillbrand (sethh)]

@Willem- We'll address the scale/shift issue separately. Then we can target this bug report to the issue of part substitution. Can you say which STEP file in your example project is not exporting (filename and refdes)?

[Willem Hillier (willemhillier)]

Update: The STEP model now imports into Fusion 360 perfectly, and I'm not sure what changed to cause it. The same issues still occur when importing into SolidWorks, but as a work-around I can import into Fusion 360, export a STEP of the assembly from there, and then import that into SolidWorks. If someone wants an example of an exported STEP file exhibiting this issue, let me know, but I think the issue isn't strictly KiCad, and is some weird compatibility issue between KiCad and SolidWorks.

[Seth Hillbrand (sethh)]

@Willem- Yes. Please indicate which components are being substituted in your export. If you can provide the STEP files for the models that are referenced, we can look into this.

[Launchpad Janitor (janitor)]

[Expired for KiCad because there has been no activity for 60 days.]