Alembic Exports: Do not force a preroll starting at frame 0

client/ayon_maya/api/alembic.py

@@ -34,7 +34,6 @@
     "userAttrPrefix": (list, tuple),
     "uvWrite": bool,
     "uvsOnly": bool,
-    "verbose": bool,
     "wholeFrameGeo": bool,
     "worldSpace": bool,
     "writeColorSets": bool,
@@ -57,7 +56,7 @@ def extract_alembic(
     melPostJobCallback=None,
     noNormals=False,
     preRoll=False,
-    preRollStartFrame=0,
+    preRollStartFrame=None,
     pythonPerFrameCallback=None,
     pythonPostJobCallback=None,
     renderableOnly=False,
@@ -119,10 +118,11 @@ def extract_alembic(
         preRoll (bool): This frame range will not be sampled.
             Defaults to False.
 
-        preRollStartFrame (float): The frame to start scene
+        preRollStartFrame (Optional[float]): The frame to start scene
             evaluation at.  This is used to set the starting frame for time
             dependent translations and can be used to evaluate run-up that
-            isn't actually translated. Defaults to 0.
+            isn't actually translated. Defaults to None, meaning no pre-roll
+            start frame will be used to roll from.
 
         pythonPerFrameCallback (Optional[str]): Python callback run per frame.
 
@@ -258,7 +258,6 @@ def extract_alembic(
         "userAttr": userAttr,
         "userAttrPrefix": userAttrPrefix,
         "stripNamespaces": stripNamespaces,
-        "verbose": verbose
     }
 
     # Validate options

client/ayon_maya/plugins/publish/extract_pointcache.py

@@ -215,6 +215,29 @@ def process(self, instance):
                 iter_visible_nodes_in_range(nodes, start=start, end=end)
             )
 
+        # Our logic is that `preroll` means:
+        # - True: include a preroll from `preRollStartFrame` to the start
+        #  frame that is not included in the exported file. Just 'roll up'
+        #  the export from there.
+        # - False: do not roll up from `preRollStartFrame`.
+        # `AbcExport` however approaches this very differently.
+        # A call to `AbcExport` allows to export multiple "jobs" of frame
+        # ranges in one go. Using `-preroll` argument there means: this one
+        # job in the full list of jobs SKIP writing these frames into the
+        # Alembic. In short, marking that job as just preroll.
+        # Then additionally, separate from `-preroll` the `AbcExport` command
+        # allows to supply `preRollStartFrame` which, when not None, means
+        # always RUN UP from that start frame. Since our `preRollStartFrame`
+        # is always an integer attribute we will convert the attributes so
+        # they behave like how we intended them initially
+        if kwargs["preRoll"]:
+            # Never mark `preRoll` as True because it would basically end up
+            # writing no samples at all. We just use this to leave
+            # `preRollStartFrame` as a number value.
+            kwargs["preRoll"] = False
+        else:
+            kwargs["preRollStartFrame"] = None
+
         shapes = self.get_members_shapes(instance)
 
         suspend = not instance.data.get("refresh", False)