diff --git a/projects/implicitron_trainer/experiment.py b/projects/implicitron_trainer/experiment.py
index 7e1b1a3b..972b44c0 100755
--- a/projects/implicitron_trainer/experiment.py
+++ b/projects/implicitron_trainer/experiment.py
@@ -74,6 +74,7 @@ from pytorch3d.implicitron.evaluation import evaluate_new_view_synthesis as eval
 from pytorch3d.implicitron.models.base import EvaluationMode, GenericModel
 from pytorch3d.implicitron.tools import model_io, vis_utils
 from pytorch3d.implicitron.tools.config import (
+    enable_get_default_args,
     get_default_args_field,
     remove_unused_components,
 )
@@ -304,6 +305,9 @@ def init_optimizer(
     return optimizer, scheduler
 
 
+enable_get_default_args(init_optimizer)
+
+
 def trainvalidate(
     model,
     stats,
@@ -663,9 +667,7 @@ def _seed_all_random_engines(seed: int):
 @dataclass(eq=False)
 class ExperimentConfig:
     generic_model_args: DictConfig = get_default_args_field(GenericModel)
-    solver_args: DictConfig = get_default_args_field(
-        init_optimizer, _allow_untyped=True
-    )
+    solver_args: DictConfig = get_default_args_field(init_optimizer)
     dataset_args: DictConfig = get_default_args_field(dataset_zoo)
     dataloader_args: DictConfig = get_default_args_field(dataloader_zoo)
     architecture: str = "generic"
diff --git a/pytorch3d/implicitron/dataset/dataloader_zoo.py b/pytorch3d/implicitron/dataset/dataloader_zoo.py
index 2a75f7a5..b5812e25 100644
--- a/pytorch3d/implicitron/dataset/dataloader_zoo.py
+++ b/pytorch3d/implicitron/dataset/dataloader_zoo.py
@@ -7,6 +7,7 @@
 from typing import Dict, Sequence
 
 import torch
+from pytorch3d.implicitron.tools.config import enable_get_default_args
 
 from .implicitron_dataset import FrameData, ImplicitronDatasetBase
 from .scene_batch_sampler import SceneBatchSampler
@@ -56,8 +57,6 @@ def dataloader_zoo(
         dataloaders: A dictionary containing the
             `"dataset_subset_name": torch_dataloader_object` key, value pairs.
     """
-
-    images_per_seq_options = tuple(images_per_seq_options)
     if dataset_name not in ["co3d_singlesequence", "co3d_multisequence"]:
         raise ValueError(f"Unsupported dataset: {dataset_name}")
 
@@ -96,3 +95,6 @@ def dataloader_zoo(
         raise ValueError(f"Unsupported dataset: {dataset_name}")
 
     return dataloaders
+
+
+enable_get_default_args(dataloader_zoo)
diff --git a/pytorch3d/implicitron/dataset/dataset_zoo.py b/pytorch3d/implicitron/dataset/dataset_zoo.py
index 1b16d817..d93bfb0d 100644
--- a/pytorch3d/implicitron/dataset/dataset_zoo.py
+++ b/pytorch3d/implicitron/dataset/dataset_zoo.py
@@ -11,6 +11,7 @@ import os
 from typing import Any, Dict, List, Optional, Sequence
 
 from iopath.common.file_io import PathManager
+from pytorch3d.implicitron.tools.config import enable_get_default_args
 
 from .implicitron_dataset import ImplicitronDataset, ImplicitronDatasetBase
 from .utils import (
@@ -100,9 +101,6 @@ def dataset_zoo(
         datasets: A dictionary containing the
             `"dataset_subset_name": torch_dataset_object` key, value pairs.
     """
-    restrict_sequence_name = tuple(restrict_sequence_name)
-    aux_dataset_kwargs = dict(aux_dataset_kwargs)
-
     datasets = {}
 
     # TODO:
@@ -222,6 +220,9 @@ def dataset_zoo(
     return datasets
 
 
+enable_get_default_args(dataset_zoo)
+
+
 def _get_co3d_set_names_mapping(
     dataset_name: str,
     test_on_train: bool,
diff --git a/pytorch3d/implicitron/models/renderer/rgb_net.py b/pytorch3d/implicitron/models/renderer/rgb_net.py
index 68c77390..e1b81587 100644
--- a/pytorch3d/implicitron/models/renderer/rgb_net.py
+++ b/pytorch3d/implicitron/models/renderer/rgb_net.py
@@ -7,6 +7,7 @@ import logging
 from typing import List, Tuple
 
 import torch
+from pytorch3d.implicitron.tools.config import enable_get_default_args
 from pytorch3d.renderer.implicit import HarmonicEmbedding, RayBundle
 from torch import nn
 
@@ -106,3 +107,6 @@ class RayNormalColoringNetwork(torch.nn.Module):
 
         x = self.tanh(x)
         return x
+
+
+enable_get_default_args(RayNormalColoringNetwork)
diff --git a/pytorch3d/implicitron/models/renderer/sdf_renderer.py b/pytorch3d/implicitron/models/renderer/sdf_renderer.py
index a969029a..735a8a8c 100644
--- a/pytorch3d/implicitron/models/renderer/sdf_renderer.py
+++ b/pytorch3d/implicitron/models/renderer/sdf_renderer.py
@@ -20,11 +20,9 @@ from .rgb_net import RayNormalColoringNetwork
 @registry.register
 class SignedDistanceFunctionRenderer(BaseRenderer, torch.nn.Module):
     render_features_dimensions: int = 3
-    ray_tracer_args: DictConfig = get_default_args_field(
-        RayTracing, _allow_untyped=True
-    )
+    ray_tracer_args: DictConfig = get_default_args_field(RayTracing)
     ray_normal_coloring_network_args: DictConfig = get_default_args_field(
-        RayNormalColoringNetwork, _allow_untyped=True
+        RayNormalColoringNetwork
     )
     bg_color: Tuple[float, ...] = (0.0,)
     soft_mask_alpha: float = 50.0
diff --git a/pytorch3d/implicitron/tools/config.py b/pytorch3d/implicitron/tools/config.py
index 0883ca76..476c4711 100644
--- a/pytorch3d/implicitron/tools/config.py
+++ b/pytorch3d/implicitron/tools/config.py
@@ -4,10 +4,10 @@
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
 
-import copy
 import dataclasses
 import inspect
 import itertools
+import sys
 import warnings
 from collections import Counter, defaultdict
 from enum import Enum
@@ -27,8 +27,7 @@ Core functionality:
 
 - expand_args_fields -- Expands a class like `dataclasses.dataclass`. Runs automatically.
 
-- get_default_args -- gets an omegaconf.DictConfig for initializing
-                       a given class or calling a given function.
+- get_default_args -- gets an omegaconf.DictConfig for initializing a given class.
 
 - run_auto_creation -- Initialises nested members. To be called in __post_init__.
 
@@ -46,6 +45,7 @@ Additional utility functions:
 
 - remove_unused_components -- used for simplifying a DictConfig instance.
 - get_default_args_field -- default for DictConfig member of another configurable.
+- enable_get_default_args -- Allows get_default_args on a function or plain class.
 
 
 1. The simplest usage of this functionality is as follows. First a schema is defined
@@ -413,34 +413,25 @@ def _is_configurable_class(C) -> bool:
     return isinstance(C, type) and issubclass(C, (Configurable, ReplaceableBase))
 
 
-def get_default_args(
-    C, *, _allow_untyped: bool = False, _do_not_process: Tuple[type, ...] = ()
-) -> DictConfig:
+def get_default_args(C, *, _do_not_process: Tuple[type, ...] = ()) -> DictConfig:
     """
-    Get the DictConfig of args to call C - which might be a type or a function.
+    Get the DictConfig corresponding to the defaults in a dataclass or
+    configurable. Normal use is to provide a dataclass can be provided as C.
+    If enable_get_default_args has been called on a function or plain class,
+    then that function or class can be provided as C.
 
     If C is a subclass of Configurable or ReplaceableBase, we make sure
-    it has been processed with expand_args_fields. If C is a dataclass,
-    including a subclass of Configurable or ReplaceableBase, the output
-    will be a typed DictConfig.
+    it has been processed with expand_args_fields.
 
     Args:
         C: the class or function to be processed
-        _allow_untyped: (internal use) If True, do not try to make the
-                        output typed when it is not a Configurable or
-                        ReplaceableBase. This avoids problems (due to local
-                        dataclasses being remembered inside the returned
-                        DictConfig and any of its DictConfig and ListConfig
-                        members) when pickling the output, but will break
-                        conversions of yaml strings to/from any emum members
-                        of C.
         _do_not_process: (internal use) When this function is called from
                     expand_args_fields, we specify any class currently being
                     processed, to make sure we don't try to process a class
                     while it is already being processed.
 
     Returns:
-        new DictConfig object
+        new DictConfig object, which is typed.
     """
     if C is None:
         return DictConfig({})
@@ -471,9 +462,46 @@ def get_default_args(
     if _is_configurable_class(C):
         raise ValueError(f"Failed to process {C}")
 
-    # regular class or function
+    if not inspect.isfunction(C) and not inspect.isclass(C):
+        raise ValueError(f"Unexpected {C}")
+
+    dataclass_name = _dataclass_name_for_function(C)
+    dataclass = getattr(sys.modules[C.__module__], dataclass_name, None)
+    if dataclass is None:
+        raise ValueError(
+            f"Cannot get args for {C}. Was enable_get_default_args forgotten?"
+        )
+
+    return OmegaConf.structured(dataclass)
+
+
+def _dataclass_name_for_function(C: Any) -> str:
+    """
+    Returns the name of the dataclass which enable_get_default_args(C)
+    creates.
+    """
+    name = f"_{C.__name__}_default_args_"
+    return name
+
+
+def enable_get_default_args(C: Any, *, overwrite: bool = True) -> None:
+    """
+    If C is a function or a plain class with an __init__ function,
+    and you want get_default_args(C) to work, then add
+    `enable_get_default_args(C)` straight after the definition of C.
+    This makes a dataclass corresponding to the default arguments of C
+    and stores it in the same module as C.
+
+    Args:
+        C: a function, or a class with an __init__ function. Must
+            have types for all its defaulted args.
+        overwrite: whether to allow calling this a second time on
+            the same function.
+    """
+    if not inspect.isfunction(C) and not inspect.isclass(C):
+        raise ValueError(f"Unexpected {C}")
+
     field_annotations = []
-    kwargs = {}
     for pname, defval in _params_iter(C):
         default = defval.default
         if default == inspect.Parameter.empty:
@@ -488,8 +516,6 @@ def get_default_args(
 
         _, annotation = _resolve_optional(defval.annotation)
 
-        kwargs[pname] = copy.deepcopy(default)
-
         if isinstance(default, set):  # force OmegaConf to convert it to ListConfig
             default = tuple(default)
 
@@ -503,13 +529,16 @@ def get_default_args(
             field_ = dataclasses.field(default=default)
         field_annotations.append((pname, defval.annotation, field_))
 
-    if _allow_untyped:
-        return DictConfig(kwargs)
-
-    # make a temp dataclass and generate a structured config from it.
-    return OmegaConf.structured(
-        dataclasses.make_dataclass(f"__{C.__name__}_default_args__", field_annotations)
-    )
+    name = _dataclass_name_for_function(C)
+    module = sys.modules[C.__module__]
+    if hasattr(module, name):
+        if overwrite:
+            warnings.warn(f"Overwriting {name} in {C.__module__}.")
+        else:
+            raise ValueError(f"Cannot overwrite {name} in {C.__module__}.")
+    dc = dataclasses.make_dataclass(name, field_annotations)
+    dc.__module__ = C.__module__
+    setattr(module, name, dc)
 
 
 def _params_iter(C):
@@ -715,9 +744,7 @@ def expand_args_fields(
     return some_class
 
 
-def get_default_args_field(
-    C, *, _allow_untyped: bool = False, _do_not_process: Tuple[type, ...] = ()
-):
+def get_default_args_field(C, *, _do_not_process: Tuple[type, ...] = ()):
     """
     Get a dataclass field which defaults to get_default_args(...)
 
@@ -729,9 +756,7 @@ def get_default_args_field(
     """
 
     def create():
-        return get_default_args(
-            C, _allow_untyped=_allow_untyped, _do_not_process=_do_not_process
-        )
+        return get_default_args(C, _do_not_process=_do_not_process)
 
     return dataclasses.field(default_factory=create)
 
diff --git a/tests/implicitron/test_config.py b/tests/implicitron/test_config.py
index 54c9d7f6..e53fe0bd 100644
--- a/tests/implicitron/test_config.py
+++ b/tests/implicitron/test_config.py
@@ -19,6 +19,7 @@ from pytorch3d.implicitron.tools.config import (
     _is_actually_dataclass,
     _ProcessType,
     _Registry,
+    enable_get_default_args,
     expand_args_fields,
     get_default_args,
     get_default_args_field,
@@ -236,6 +237,8 @@ class TestConfig(unittest.TestCase):
             def __init__(self, a: Any = 1, b: Any = 2):
                 self.a, self.b = a, b
 
+        enable_get_default_args(Foo)
+
         @dataclass()
         class Bar:
             aa: int = 9
@@ -480,10 +483,14 @@ class TestConfig(unittest.TestCase):
             def get_tuple(self):
                 return self.tuple_member
 
+        enable_get_default_args(SimpleClass)
+
         def f(*, a: int = 3, b: str = "kj"):
             self.assertEqual(a, 3)
             self.assertEqual(b, "kj")
 
+        enable_get_default_args(f)
+
         class C(Configurable):
             simple: DictConfig = get_default_args_field(SimpleClass)
             # simple2: SimpleClass2 = SimpleClass2()
@@ -567,10 +574,14 @@ class TestConfig(unittest.TestCase):
         def C_fn(a: A = A.B1):
             pass
 
+        enable_get_default_args(C_fn)
+
         class C_cl:
             def __init__(self, a: A = A.B1) -> None:
                 pass
 
+        enable_get_default_args(C_cl)
+
         for C_ in [C, C_fn, C_cl]:
             base = get_default_args(C_)
             self.assertEqual(base.a, A.B1)
@@ -586,14 +597,20 @@ class TestConfig(unittest.TestCase):
             self.assertEqual(remerged.a, A.B1)
 
     def test_pickle(self):
-        def f(a: int = 1, b: str = "3"):
+        def func(a: int = 1, b: str = "3"):
             pass
 
-        args = get_default_args(f, _allow_untyped=True)
+        enable_get_default_args(func)
+
+        args = get_default_args(func)
         args2 = pickle.loads(pickle.dumps(args))
         self.assertEqual(args2.a, 1)
         self.assertEqual(args2.b, "3")
 
+        args_regenerated = get_default_args(func)
+        pickle.dumps(args_regenerated)
+        pickle.dumps(args)
+
     def test_remove_unused_components(self):
         struct = get_default_args(MainTest)
         struct.n_ids = 32
@@ -674,6 +691,9 @@ class MockClassWithInit:  # noqa: B903
         self.field_reference_type = field_reference_type
 
 
+enable_get_default_args(MockClassWithInit)
+
+
 class TestRawClasses(unittest.TestCase):
     def setUp(self) -> None:
         self._instances = {