diff --git a/pytorch3d/implicitron/models/implicit_function/base.py b/pytorch3d/implicitron/models/implicit_function/base.py
index 742fde169..2e0c77984 100644
--- a/pytorch3d/implicitron/models/implicit_function/base.py
+++ b/pytorch3d/implicitron/models/implicit_function/base.py
@@ -19,6 +19,7 @@ def __init__(self):
     @abstractmethod
     def forward(
         self,
+        *,
         ray_bundle: RayBundle,
         fun_viewpool=None,
         camera: Optional[CamerasBase] = None,
diff --git a/pytorch3d/implicitron/models/implicit_function/idr_feature_field.py b/pytorch3d/implicitron/models/implicit_function/idr_feature_field.py
index 09a9fa304..557ba1387 100644
--- a/pytorch3d/implicitron/models/implicit_function/idr_feature_field.py
+++ b/pytorch3d/implicitron/models/implicit_function/idr_feature_field.py
@@ -3,14 +3,15 @@
 #              implicit_differentiable_renderer.py
 # Copyright (c) 2020 Lior Yariv
 import math
-from typing import Tuple
+from typing import Optional, Tuple
 
 import torch
 from pytorch3d.implicitron.tools.config import registry
-from pytorch3d.renderer.implicit import HarmonicEmbedding
+from pytorch3d.renderer.implicit import HarmonicEmbedding, RayBundle
 from torch import nn
 
 from .base import ImplicitFunctionBase
+from .utils import get_rays_points_world
 
 
 @registry.register
@@ -125,14 +126,16 @@ def __post_init__(self):
     #  inconsistently.
     def forward(
         self,
-        # ray_bundle: RayBundle,
-        rays_points_world: torch.Tensor,  # TODO: unify the APIs
+        *,
+        ray_bundle: Optional[RayBundle] = None,
+        rays_points_world: Optional[torch.Tensor] = None,
         fun_viewpool=None,
         global_code=None,
+        **kwargs,
     ):
         # this field only uses point locations
-        # rays_points_world = ray_bundle_to_ray_points(ray_bundle)
         # rays_points_world.shape = [minibatch x ... x pts_per_ray x 3]
+        rays_points_world = get_rays_points_world(ray_bundle, rays_points_world)
 
         if rays_points_world.numel() == 0 or (
             self.embed_fn is None and fun_viewpool is None and global_code is None
@@ -179,4 +182,4 @@ def forward(
                 # pyre-fixme[29]: `Union[torch.Tensor, torch.nn.Module]` is not a function.
                 x = self.softplus(x)
 
-        return x  # TODO: unify the APIs
+        return x
diff --git a/pytorch3d/implicitron/models/implicit_function/neural_radiance_field.py b/pytorch3d/implicitron/models/implicit_function/neural_radiance_field.py
index 78a3c8a44..d325c798c 100644
--- a/pytorch3d/implicitron/models/implicit_function/neural_radiance_field.py
+++ b/pytorch3d/implicitron/models/implicit_function/neural_radiance_field.py
@@ -129,6 +129,7 @@ def allows_multiple_passes() -> bool:
 
     def forward(
         self,
+        *,
         ray_bundle: RayBundle,
         fun_viewpool=None,
         camera: Optional[CamerasBase] = None,
diff --git a/pytorch3d/implicitron/models/implicit_function/scene_representation_networks.py b/pytorch3d/implicitron/models/implicit_function/scene_representation_networks.py
index b7f10a95a..c701c54c0 100644
--- a/pytorch3d/implicitron/models/implicit_function/scene_representation_networks.py
+++ b/pytorch3d/implicitron/models/implicit_function/scene_representation_networks.py
@@ -349,6 +349,7 @@ def raymarch_function_tweak_args(cls, type, args: DictConfig) -> None:
 
     def forward(
         self,
+        *,
         ray_bundle: RayBundle,
         fun_viewpool=None,
         camera: Optional[CamerasBase] = None,
@@ -408,6 +409,7 @@ def hypernet_tweak_args(cls, type, args: DictConfig) -> None:
 
     def forward(
         self,
+        *,
         ray_bundle: RayBundle,
         fun_viewpool=None,
         camera: Optional[CamerasBase] = None,
diff --git a/pytorch3d/implicitron/models/implicit_function/utils.py b/pytorch3d/implicitron/models/implicit_function/utils.py
index 9a26aff3f..9b401c489 100644
--- a/pytorch3d/implicitron/models/implicit_function/utils.py
+++ b/pytorch3d/implicitron/models/implicit_function/utils.py
@@ -10,7 +10,9 @@
 
 import torch.nn.functional as F
 from pytorch3d.common.compat import prod
+from pytorch3d.renderer import ray_bundle_to_ray_points
 from pytorch3d.renderer.cameras import CamerasBase
+from pytorch3d.renderer.implicit import RayBundle
 
 
 def broadcast_global_code(embeds: torch.Tensor, global_code: torch.Tensor):
@@ -185,3 +187,31 @@ def interpolate_volume(
         **kwargs,
     )
     return out[:, :, :, 0, 0].permute(0, 2, 1)
+
+
+def get_rays_points_world(
+    ray_bundle: Optional[RayBundle] = None,
+    rays_points_world: Optional[torch.Tensor] = None,
+) -> torch.Tensor:
+    """
+    Converts the ray_bundle to rays_points_world if rays_points_world is not defined
+    and raises error if both are defined.
+
+    Args:
+        ray_bundle: A RayBundle object or None
+        rays_points_world: A torch.Tensor representing ray points converted to
+            world coordinates
+    Returns:
+        A torch.Tensor representing ray points converted to world coordinates
+            of shape [minibatch x ... x pts_per_ray x 3].
+    """
+    if rays_points_world is not None and ray_bundle is not None:
+        raise ValueError(
+            "Cannot define both rays_points_world and ray_bundle,"
+            + " one has to be None."
+        )
+    if rays_points_world is not None:
+        return rays_points_world
+    if ray_bundle is not None:
+        return ray_bundle_to_ray_points(ray_bundle)
+    raise ValueError("ray_bundle and rays_points_world cannot both be None")
diff --git a/pytorch3d/implicitron/models/renderer/lstm_renderer.py b/pytorch3d/implicitron/models/renderer/lstm_renderer.py
index 64cd89cf0..c5ce094f5 100644
--- a/pytorch3d/implicitron/models/renderer/lstm_renderer.py
+++ b/pytorch3d/implicitron/models/renderer/lstm_renderer.py
@@ -118,7 +118,7 @@ def forward(
 
             # eval the raymarching function
             raymarch_features, _ = implicit_function(
-                ray_bundle_t,
+                ray_bundle=ray_bundle_t,
                 raymarch_features=None,
             )
             if self.verbose:
diff --git a/pytorch3d/implicitron/models/renderer/multipass_ea.py b/pytorch3d/implicitron/models/renderer/multipass_ea.py
index 89bceae17..61cf0d4c3 100644
--- a/pytorch3d/implicitron/models/renderer/multipass_ea.py
+++ b/pytorch3d/implicitron/models/renderer/multipass_ea.py
@@ -148,7 +148,7 @@ def _run_raymarcher(
         )
 
         output = self.raymarcher(
-            *implicit_functions[0](ray_bundle),
+            *implicit_functions[0](ray_bundle=ray_bundle),
             ray_lengths=ray_bundle.lengths,
             density_noise_std=density_noise_std,
         )
diff --git a/pytorch3d/implicitron/models/renderer/sdf_renderer.py b/pytorch3d/implicitron/models/renderer/sdf_renderer.py
index 15e07dc97..2f0e626c9 100644
--- a/pytorch3d/implicitron/models/renderer/sdf_renderer.py
+++ b/pytorch3d/implicitron/models/renderer/sdf_renderer.py
@@ -101,7 +101,7 @@ def forward(
         object_mask = object_mask.bool()
 
         implicit_function = implicit_functions[0]
-        implicit_function_gradient = functools.partial(gradient, implicit_function)
+        implicit_function_gradient = functools.partial(_gradient, implicit_function)
 
         # object_mask: silhouette of the object
         batch_size, *spatial_size, _ = ray_bundle.lengths.shape
@@ -113,7 +113,7 @@ def forward(
 
         with torch.no_grad(), evaluating(implicit_function):
             points, network_object_mask, dists = self.ray_tracer(
-                sdf=lambda x: implicit_function(x)[
+                sdf=lambda x: implicit_function(rays_points_world=x)[
                     :, 0
                 ],  # TODO: get rid of this wrapper
                 cam_loc=cam_loc,
@@ -125,7 +125,7 @@ def forward(
         depth = dists.reshape(batch_size, num_pixels, 1)
         points = (cam_loc + depth * ray_dirs).reshape(-1, 3)
 
-        sdf_output = implicit_function(points)[:, 0:1]
+        sdf_output = implicit_function(rays_points_world=points)[:, 0:1]
         # NOTE most of the intermediate variables are flattened for
         # no apparent reason (here and in the ray tracer)
         ray_dirs = ray_dirs.reshape(-1, 3)
@@ -157,7 +157,7 @@ def forward(
 
             points_all = torch.cat([surface_points, eikonal_points], dim=0)
 
-            output = implicit_function(surface_points)
+            output = implicit_function(rays_points_world=surface_points)
             surface_sdf_values = output[
                 :N, 0:1
             ].detach()  # how is it different from sdf_output?
@@ -181,7 +181,9 @@ def forward(
             grad_theta = None
 
         empty_render = differentiable_surface_points.shape[0] == 0
-        features = implicit_function(differentiable_surface_points)[None, :, 1:]
+        features = implicit_function(rays_points_world=differentiable_surface_points)[
+            None, :, 1:
+        ]
         normals_full = features.new_zeros(
             batch_size, *spatial_size, 3, requires_grad=empty_render
         )
@@ -260,13 +262,13 @@ def _sample_network(
 
 
 @torch.enable_grad()
-def gradient(module, x):
-    x.requires_grad_(True)
-    y = module.forward(x)[:, :1]
+def _gradient(module, rays_points_world):
+    rays_points_world.requires_grad_(True)
+    y = module.forward(rays_points_world=rays_points_world)[:, :1]
     d_output = torch.ones_like(y, requires_grad=False, device=y.device)
     gradients = torch.autograd.grad(
         outputs=y,
-        inputs=x,
+        inputs=rays_points_world,
         grad_outputs=d_output,
         create_graph=True,
         retain_graph=True,
diff --git a/tests/implicitron/test_srn.py b/tests/implicitron/test_srn.py
index a50c341c3..f6905ef4d 100644
--- a/tests/implicitron/test_srn.py
+++ b/tests/implicitron/test_srn.py
@@ -44,7 +44,7 @@ def test_srn_implicit_function(self):
         implicit_function = SRNImplicitFunction()
         device = torch.device("cpu")
         bundle = self._get_bundle(device=device)
-        rays_densities, rays_colors = implicit_function(bundle)
+        rays_densities, rays_colors = implicit_function(ray_bundle=bundle)
         out_features = implicit_function.raymarch_function.out_features
         self.assertEqual(
             rays_densities.shape,
@@ -62,7 +62,9 @@ def test_srn_hypernet_implicit_function(self):
         implicit_function.to(device)
         global_code = torch.rand(_BATCH_SIZE, latent_dim_hypernet, device=device)
         bundle = self._get_bundle(device=device)
-        rays_densities, rays_colors = implicit_function(bundle, global_code=global_code)
+        rays_densities, rays_colors = implicit_function(
+            ray_bundle=bundle, global_code=global_code
+        )
         out_features = implicit_function.hypernet.out_features
         self.assertEqual(
             rays_densities.shape,