Added support for proxy attributes

src/mutils/animation.py

@@ -651,8 +651,12 @@ def save(
                     if not FIX_SAVE_ANIM_REFERENCE_LOCKED_ERROR:
                         mutils.disconnectAll(dstNode)
 
-                    # Make sure we delete all proxy attributes, otherwise pasteKey will duplicate keys
-                    mutils.Attribute.deleteProxyAttrs(dstNode)
+                    # Collect all the proxy attributes and un-proxy them before export. This way they will be
+                    # saved as standard attributes and all their values will be pasted correctly when loaded back.
+                    proxyAttrs = mutils.Attribute.collectProxyAttrs(dstNode)
+                    for proxy in proxyAttrs:
+                        logger.debug("proxy attribute: %s", proxy)
+                        proxy.unProxy()
                     maya.cmds.pasteKey(dstNode)
 
                     attrs = maya.cmds.listAttr(dstNode, unlocked=True, keyable=True) or []
@@ -811,10 +815,6 @@ def load(
                         logger.debug('Skipping attribute: The destination attribute "%s" does not exist!' % dstAttr.fullname())
                         continue
 
-                    if dstAttr.isProxy():
-                        logger.debug('Skipping attribute: The destination attribute "%s" is a proxy attribute!', dstAttr.fullname())
-                        continue
-
                     srcCurve = self.animCurve(srcNode.name(), attr, withNamespace=True)
 
                     if srcCurve:

src/mutils/attribute.py

@@ -82,12 +82,11 @@ def listAttr(cls, name, **kwargs):
         return [cls(name, attr) for attr in attrs]
 
     @classmethod
-    def deleteProxyAttrs(cls, name):
-        """Delete all the proxy attributes for the given object name."""
+    def collectProxyAttrs(cls, name):
         attrs = cls.listAttr(name, unlocked=True, keyable=True) or []
         for attr in attrs:
             if attr.isProxy():
-                attr.delete()
+                yield attr
 
     def __init__(self, name, attr=None, value=None, type=None, cache=True):
         """
@@ -181,6 +180,28 @@ def isProxy(self):
 
         return maya.cmds.addAttr(self.fullname(), query=True, usedAsProxy=True)
 
+    def unProxy(self):
+        """
+        Converts the attribute from proxy back to dynamic.
+
+        :rtype: None
+        """
+        # Collect all the data before deleting the attribute, as that will require it to
+        # still be alive.
+        name = self.attr()
+        type_ = self.type()
+        value = self.value()
+        if self.isProxy():
+            self.delete()
+        # Re-create the attribute in non-proxy mode.
+        maya.cmds.addAttr(
+            self.name(),
+            longName=name,
+            attributeType=type_,
+            defaultValue=value,
+            keyable=True,
+        )
+
     def delete(self):
         """Delete the attribute"""
         maya.cmds.deleteAttr(self.fullname())
@@ -421,10 +442,6 @@ def setAnimCurve(self, curve, time, option, source=None, connect=False):
         fullname = self.fullname()
         startTime, endTime = time
 
-        if self.isProxy():
-            logger.debug("Cannot set anim curve for proxy attribute")
-            return
-
         if not self.exists():
             logger.debug("Attr does not exists")
             return
@@ -492,7 +509,13 @@ def animCurve(self):
 
         if self.exists():
 
-            n = self.listConnections(plugs=True, destination=False)
+            # Find the keys connected to the current attribute. If the attribute is a proxy, the anim keys will
+            # actually be connected to the node where the source of the proxy attribute comes from, so traverse
+            # that to find the keys.
+            animSource = self.fullname()
+            if self.isProxy():
+                animSource = self.listConnections(plugs=True, destination=False)
+            n = maya.cmds.listConnections(animSource, plugs=True, destination=False)
 
             if n and "animCurve" in maya.cmds.nodeType(n):
                 result = n