[al]Updating AL USDMaya's NurbsCurve static import export to use USD's curve spec

[NickWu]

Previously, AL USDMaya was exporting maya NurbsCurves as-is but USD's NurbsCurve spec is different from maya's. From USD's doc, we can see it uses a different knot spec than Maya does:
https://graphics.pixar.com/usd/release/api/class_usd_geom_nurbs_curves.html#details

Also, in Maya's MFnNurbsCurve API doc, it says:

Managing different knot representations in external applications

Note that some third party applications use a different format for knots, where the number of knots required for a curve is M+2N+1 rather than M+2N-1 as used in Maya. Both knot representations are equivalent mathematically. To convert from one of these external representations into the Maya representation, simply omit the first and last knots from the external representation when creating the Maya representation. To convert from the Maya representation into the external representation, add two new knots at the beginning and end of the Maya knot sequence. The value of these new knots depends on the existing knot sequence. For a knot sequence with multiple end knots, simply duplicate the existing first and last knots once more, for example:

Maya representation: {0,0,0,...,N,N,N}
External representation: {0,0,0,0,...,N,N,N,N}

For a knot sequence with uniform end knots, create the new knots offset at an interval equal to the existing first and last knot intervals, for example:

Maya representation: {0,1,2,...,N,N+1,N+2}
External representation: {-1,0,1,2,...,N,N+1,N+2,N+3}

[seando-adsk]

@NickWu It says there are conflicts that must be resolved. Can you fix that before we start the review/preflight process.

[NickWu]

@NickWu It says there are conflicts that must be resolved. Can you fix that before we start the review/preflight process.

Hey @seando-adsk , I have fixed the conflicts. Thank you.

[seando-adsk]

@pierrebai-adsk Can you have a quick look at these changes in the AL plugin? I assume their team already reviewed it so just a quick check by us.

[pierrebai-adsk]

Only inconsequential typos.

[NickWu]

Only inconsequential typos.

Thank you for taking a look. I'll update it shortly.

[seando-adsk]

@NickWu I ran the preflight and there is some failures. Can you please have a look.

[NickWu]

Hi @seando-adsk , I don't see any error message from the build_preflight saying why it's failing. Do you have this information?

[seando-adsk]

• Click on the "Checks" tab
• Then on left pane at the bottom click on "Pre-flight build on pull request"
• At the bottom click on "build logs"
• This will download a .zip file with all the logs
• The "xxx_result.txt" file shows all the builds that failed
• Then you can open each individual log to see the error(s)
• I checked on build and saw that test "TestAdditionalTranslators" failed

[NickWu]

• Click on the "Checks" tab
• Then on left pane at the bottom click on "Pre-flight build on pull request"
• At the bottom click on "build logs"
• This will download a .zip file with all the logs
• The "xxx_result.txt" file shows all the builds that failed
• Then you can open each individual log to see the error(s)
• I checked on build and saw that test "TestAdditionalTranslators" failed

Hey @seando-adsk , I have fixed the failed tests. Thanks.

[NickWu]

Hey @seando-adsk , is it all good to merge this one?

[seando-adsk]

@NickWu We've had some issues with our preflight for the last 2 weeks because of a problem with Github. We implemented a workaround and our preflight system is now functional again.

I've launched the preflight on this PR. Assuming it passes, it will be all good to merge.

[NickWu]

Hi @seando-adsk , I found pre-flight tests for Windows failed with the following error:

[2023-05-11T22:36:55.367Z]     Runtime Error: in WriteToFile at line 358 of S:\jenkins\workspace\ECP\ecg-usd-build\ecg-usd-full-windows\ecg-usd-build\usd\pxr\usd\sdf\textFileFormat.cpp -- Failed to rename temporary file 'w:\build\relwithdebinfo\test\temporary\testadditionaltranslators/test_USDNurbsCurveExportImport_nxpvfb.3oxy6k' to 'w:\build\relwithdebinfo\test\temporary\testadditionaltranslators\test_USDNurbsCurveExportImport_nxpvfb.usda': Access is denied.

Looks to be a permission error?

[seando-adsk]

@NickWu There were a many builds which had test failure TestAdditionalTranslators. Are you sure that isn't from your changes?

[NickWu]

@NickWu There were a many builds which had test failure TestAdditionalTranslators. Are you sure that isn't from your changes?

Sorry for the late reply. I got a chance to look at this today and I found there is a piece of code in the test that runs fine on Linux but problematic on Windows. I'll update the test shortly.

[NickWu]

Hi @seando-adsk , I can see there is a test failing due to VP2 Error : Failed to initialize graphics device on the following test:
MayaUsd - Maya 2022 [USD min, Python 2, Interactive] - Branch Preflight (Windows): failed -- /job/ecg-mayausd-branch-preflight-2022-python2-pxrusd-min-interactive-windows/1043

This doesn't look like it's related to my PR here. Could you take a look?

[seando-adsk]

@NickWu Yes don't worry that failure is not related to your changes. One of our internal build machines is having issues and is being looked at. Once fixed I'll re-run the preflight build.

[seando-adsk]

Re-ran preflight - random test timeout on Maya 2022 (py3) Windows with testUsdExportUVTransforms. Ready for merge.