diff --git a/common/include/interp.h b/common/include/interp.h
index 475c437f5..99ac65456 100644
--- a/common/include/interp.h
+++ b/common/include/interp.h
@@ -47,7 +47,7 @@ void g3_draw_polygon_model(grs_bitmap *const *model_bitmaps, polygon_model_point
 //init code for bitmap models
 int16_t g3_init_polygon_model(std::span<uint8_t> model);
 #if defined(DXX_BUILD_DESCENT_I)
-void g3_validate_polygon_model(uint8_t *model_ptr, std::size_t model_size);
+void g3_validate_polygon_model(std::span<uint8_t> model);
 #endif
 }
 #endif
diff --git a/similar/3d/interp.cpp b/similar/3d/interp.cpp
index 98cc4983e..f23b13127 100644
--- a/similar/3d/interp.cpp
+++ b/similar/3d/interp.cpp
@@ -967,12 +967,12 @@ static void validate_model_sub(uint8_t *const model_sub_ptr, const std::span<con
 
 }
 
-void g3_validate_polygon_model(uint8_t *const model_ptr, const std::size_t model_size)
+void g3_validate_polygon_model(const std::span<uint8_t> model)
 {
 #ifndef NDEBUG
 	nest_count = 0;
 #endif
-	return validate_model_sub(model_ptr, std::span{model_ptr, model_size});
+	return validate_model_sub(model.data(), model);
 }
 #endif
 
diff --git a/similar/main/polyobj.cpp b/similar/main/polyobj.cpp
index 345129de8..e3c997e36 100644
--- a/similar/main/polyobj.cpp
+++ b/similar/main/polyobj.cpp
@@ -645,7 +645,7 @@ void polygon_model_data_read(polymodel *pm, PHYSFS_File *fp)
 	if constexpr (words_bigendian)
 		swap_polygon_model_data(pm->model_data.get());
 #if defined(DXX_BUILD_DESCENT_I)
-	g3_validate_polygon_model(pm->model_data.get(), model_data_size);
+	g3_validate_polygon_model(std::span{pm->model_data.get(), model_data_size});
 #elif defined(DXX_BUILD_DESCENT_II)
 	g3_init_polygon_model(std::span{pm->model_data.get(), model_data_size});
 #endif