diff --git a/pcdet/ops/pointnet2/pointnet2_stack/src/ball_query.cpp b/pcdet/ops/pointnet2/pointnet2_stack/src/ball_query.cpp
new file mode 100644
index 0000000..3376f75
--- /dev/null
+++ b/pcdet/ops/pointnet2/pointnet2_stack/src/ball_query.cpp
@@ -0,0 +1,45 @@
+/*
+Stacked-batch-data version of ball query, modified from the original implementation of official PointNet++ codes.
+Written by Shaoshuai Shi
+All Rights Reserved 2019-2020.
+*/
+
+
+#include <torch/serialize/tensor.h>
+#include <vector>
+#include <cuda.h>
+#include <cuda_runtime_api.h>
+#include "ball_query_gpu.h"
+
+#define CHECK_CUDA(x) do { \
+  if (!x.type().is_cuda()) { \
+    fprintf(stderr, "%s must be CUDA tensor at %s:%d\n", #x, __FILE__, __LINE__); \
+    exit(-1); \
+  } \
+} while (0)
+#define CHECK_CONTIGUOUS(x) do { \
+  if (!x.is_contiguous()) { \
+    fprintf(stderr, "%s must be contiguous tensor at %s:%d\n", #x, __FILE__, __LINE__); \
+    exit(-1); \
+  } \
+} while (0)
+#define CHECK_INPUT(x) CHECK_CUDA(x);CHECK_CONTIGUOUS(x)
+
+
+int ball_query_wrapper_stack(int B, int M, float radius, int nsample,
+    at::Tensor new_xyz_tensor, at::Tensor new_xyz_batch_cnt_tensor,
+    at::Tensor xyz_tensor, at::Tensor xyz_batch_cnt_tensor, at::Tensor idx_tensor) {
+    CHECK_INPUT(new_xyz_tensor);
+    CHECK_INPUT(xyz_tensor);
+    CHECK_INPUT(new_xyz_batch_cnt_tensor);
+    CHECK_INPUT(xyz_batch_cnt_tensor);
+
+    const float *new_xyz = new_xyz_tensor.data<float>();
+    const float *xyz = xyz_tensor.data<float>();
+    const int *new_xyz_batch_cnt = new_xyz_batch_cnt_tensor.data<int>();
+    const int *xyz_batch_cnt = xyz_batch_cnt_tensor.data<int>();
+    int *idx = idx_tensor.data<int>();
+
+    ball_query_kernel_launcher_stack(B, M, radius, nsample, new_xyz, new_xyz_batch_cnt, xyz, xyz_batch_cnt, idx);
+    return 1;
+}