diff --git a/servers/rendering/renderer_rd/shaders/effects/octmap_roughness.glsl b/servers/rendering/renderer_rd/shaders/effects/octmap_roughness.glsl
index 7b910d5840..f9c35ef5aa 100644
--- a/servers/rendering/renderer_rd/shaders/effects/octmap_roughness.glsl
+++ b/servers/rendering/renderer_rd/shaders/effects/octmap_roughness.glsl
@@ -29,7 +29,8 @@ void main() {
 			float solid_angle_texel = 4.0 * M_PI / float(params.dest_size * params.dest_size);
 			float roughness2 = params.roughness * params.roughness;
 			float roughness4 = roughness2 * roughness2;
-			vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+
+			vec3 UpVector = abs(N.y) < 0.999 ? vec3(0.0, 1.0, 0.0) : vec3(0.0, 0.0, 1.0);
 			mat3 T;
 			T[0] = normalize(cross(UpVector, N));
 			T[1] = cross(N, T[0]);
diff --git a/servers/rendering/renderer_rd/shaders/effects/octmap_roughness_raster.glsl b/servers/rendering/renderer_rd/shaders/effects/octmap_roughness_raster.glsl
index e5a0efc407..d74199ea4b 100644
--- a/servers/rendering/renderer_rd/shaders/effects/octmap_roughness_raster.glsl
+++ b/servers/rendering/renderer_rd/shaders/effects/octmap_roughness_raster.glsl
@@ -43,7 +43,8 @@ void main() {
 		float solid_angle_texel = 4.0 * M_PI / (params.size * params.size);
 		float roughness2 = params.roughness * params.roughness;
 		float roughness4 = roughness2 * roughness2;
-		vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+
+		vec3 UpVector = abs(N.y) < 0.999 ? vec3(0.0, 1.0, 0.0) : vec3(0.0, 0.0, 1.0);
 		mat3 T;
 		T[0] = normalize(cross(UpVector, N));
 		T[1] = cross(N, T[0]);