From 8c0c9b5276c1ca21c0b49d1d4fb4ccacce259cca Mon Sep 17 00:00:00 2001
From: Mr-Neutr0n <64578610+Mr-Neutr0n@users.noreply.github.com>
Date: Thu, 12 Feb 2026 00:04:03 +0530
Subject: [PATCH] Fix AttributeError in RayCollisionFunction.backward

RayCollisionFunction.forward correctly saves tensors via
ctx.save_for_backward(), but backward() retrieves them using the
non-existent attribute ctx.input_tensors instead of the correct
ctx.saved_tensors. This causes an AttributeError whenever gradients
are backpropagated through checkpointed ray casting (i.e., when
cast_rays is called with checkpoint=True).
---
 shap_e/rendering/raycast/cast.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/shap_e/rendering/raycast/cast.py b/shap_e/rendering/raycast/cast.py
index 7ef357128..5252ddf24 100644
--- a/shap_e/rendering/raycast/cast.py
+++ b/shap_e/rendering/raycast/cast.py
@@ -111,7 +111,7 @@ def forward(
     def backward(
         ctx, _collides_grad, ray_dists_grad, _tri_indices_grad, barycentric_grad, normals_grad
     ):
-        origins, directions, faces, vertices = ctx.input_tensors
+        origins, directions, faces, vertices = ctx.saved_tensors
 
         origins = origins.detach().requires_grad_(True)
         directions = directions.detach().requires_grad_(True)