diff --git a/source/blender/blenlib/BLI_math_matrix.h b/source/blender/blenlib/BLI_math_matrix.h
index 939c4348461..d8719f399ae 100644
--- a/source/blender/blenlib/BLI_math_matrix.h
+++ b/source/blender/blenlib/BLI_math_matrix.h
@@ -84,7 +84,7 @@ void mul_v3_m4v3(float r[3], float M[4][4], float v[3]);
 void mul_mat3_m4_v3(float M[4][4], float r[3]);
 void mul_m4_v4(float M[4][4], float r[4]);
 void mul_v4_m4v4(float r[4], float M[4][4], float v[4]);
-void mul_project_m4_v4(float M[4][4], float r[3]);
+void mul_project_m4_v3(float M[4][4], float vec[3]);
 
 void mul_m3_v3(float M[3][3], float r[3]);
 void mul_v3_m3v3(float r[3], float M[3][3], float a[3]);
diff --git a/source/blender/blenlib/intern/math_matrix.c b/source/blender/blenlib/intern/math_matrix.c
index 9fde87d734f..5edf6e28d4c 100644
--- a/source/blender/blenlib/intern/math_matrix.c
+++ b/source/blender/blenlib/intern/math_matrix.c
@@ -340,11 +340,9 @@ void mul_mat3_m4_v3(float mat[][4], float *vec)
 	vec[2]= x*mat[0][2] + y*mat[1][2] + mat[2][2]*vec[2];
 }
 
-void mul_project_m4_v4(float mat[][4], float *vec)
+void mul_project_m4_v3(float mat[][4], float vec[3])
 {
-	float w;
-
-	w = vec[0]*mat[0][3] + vec[1]*mat[1][3] + vec[2]*mat[2][3] + mat[3][3];
+	const float w= vec[0]*mat[0][3] + vec[1]*mat[1][3] + vec[2]*mat[2][3] + mat[3][3];
 	mul_m4_v3(mat, vec);
 
 	vec[0] /= w;
diff --git a/source/blender/modifiers/intern/MOD_uvproject.c b/source/blender/modifiers/intern/MOD_uvproject.c
index b054a5b0a6e..a5d2e0b38c7 100644
--- a/source/blender/modifiers/intern/MOD_uvproject.c
+++ b/source/blender/modifiers/intern/MOD_uvproject.c
@@ -271,7 +271,7 @@ static DerivedMesh *uvprojectModifier_do(UVProjectModifierData *umd,
 	/* if only one projector, project coords to UVs */
 	if(num_projectors == 1 && projectors[0].uci==NULL)
 		for(i = 0, co = coords; i < numVerts; ++i, ++co)
-			mul_project_m4_v4(projectors[0].projmat, *co);
+			mul_project_m4_v3(projectors[0].projmat, *co);
 
 	mface = dm->getFaceArray(dm);
 	numFaces = dm->getNumFaces(dm);
@@ -345,11 +345,11 @@ static DerivedMesh *uvprojectModifier_do(UVProjectModifierData *umd,
 						project_from_camera(tface->uv[3], coords[mf->v4], best_projector->uci);
 				}
 				else {
-					mul_project_m4_v4(best_projector->projmat, co1);
-					mul_project_m4_v4(best_projector->projmat, co2);
-					mul_project_m4_v4(best_projector->projmat, co3);
+					mul_project_m4_v3(best_projector->projmat, co1);
+					mul_project_m4_v3(best_projector->projmat, co2);
+					mul_project_m4_v3(best_projector->projmat, co3);
 					if(mf->v4)
-						mul_project_m4_v4(best_projector->projmat, co4);
+						mul_project_m4_v3(best_projector->projmat, co4);
 
 					/* apply transformed coords as UVs */
 					tface->uv[0][0] = co1[0];