Cryptomatte Metadata names from Blender still not fully supported

[aliasguru]

Hi there,

This is a follow-up ticket on the Metadata naming issue. Basically, when Nuke imports the Layers, it replaces certain characters with an underscore, but does not update the metadata that comes with it. This is known and handled partially in the other report.

The problem is that Nuke replaces much more than just dots. Actually it seems that only alphanumeric digits plus underscores and dashes are ok. The fact that the default view layer name in Blender is View Layer, which Nuke turns into View_Layer, doesn't exactly help. To fix this, I suggest changing the def _legal_nuke_layer_name to the code below:

def _legal_nuke_layer_name(name):
    """ Blender produces channels with certain characters in the name, which Nuke 
    changes to "_". We have to make sure we handle Cryptomattes
    that are built this way. Doing this by only allowing alphanumeric
    output plus dash and underscores
    """
    return "".join([x if x.lower() in 'abcdefghijklmnopqrstuvwxyz1234567890_-' else '_' for x in name])

This reverses the logic. Instead of stripping out illegal characters, it allows the legal ones. We tested this internally and it proved to work for our cases.

[aliasguru]

I have opened a pull request for easier merge

[jonahfriedman]

Thanks for that, @aliasguru. Sorry it's taken so long to get to this.