Hi all,
Does anyone have experience with automated testing of CAD software, especially if the rendering of a model is correct?
Many thanks in advance!
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No experience here, but from testing related areas around graphics, I’d assume your best bet is to use image comparison of screenshot taken of rendering of model against a saved benchmark screenshot for what is expected. And comparing using either absolute comparison (exact match) or with fuzzy logic compare where it can be close enough rendering for how things look depending on the image recognition/comparison tool features available. The screenshot compare option could also be export to file and compare file as well (for PDF, PNG, SVG, etc. formats)
And if not validating exact end user representation/visualization of the data, the other way might be back end rendering validation, comparing “state” value of the rendered object (the binary data, the hash/checksum)
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No not personally, sounds tricky. Sounds like you are in a similar position to I am with my current job…
When you say you want to assert if the rendering of the model is correct, could you maybe be more specific? Do you mean if each pixel is the correct colour etc, or do you mean that the 3D model is correct?
The former could be very hard, as, I would imagine, different GPUs (AMD / nVidia etc) could yield different results, as well as other environmental factors such as the display settings (DPI etc)
I am not sure I even see the value in that (ie the GPU / DirectX / OpenGL etc is not under test surely?), so I would say that if it’s the latter that you are interested in, then exporting the model (eg to STEP or something) and then asserting that each vertex etc is present and correct is probably the way to go.
A simple CRC check style compare is probably not even gonna be sufficient there though, as there would be multiple valid versions of the file (ie order of each vertex within the file is not important - that they are all present and correct is)
This is inded what I mean. 
Are the Devs able to help with testability?
You might find some blogs etc from Autodesk or Solidworks. For example: Testing Fusion
The gaming industry might also provide some insights as they have similar concepts.
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