diff --git a/zUtil_Deformation/gtDefShapeFunctionsFwdProj.m b/zUtil_Deformation/gtDefShapeFunctionsFwdProj.m
index 0fe7f99a8ad62579f05bbb310b4e4a42b75ace32..77db45bb9a365be923724d5df58e3c46f7d629d5 100644
--- a/zUtil_Deformation/gtDefShapeFunctionsFwdProj.m
+++ b/zUtil_Deformation/gtDefShapeFunctionsFwdProj.m
@@ -47,6 +47,9 @@ function shape_funcs = gtDefShapeFunctionsFwdProj(sampler, varargin)
     voxel_sampling = voxel_size ./ space_res * conf.factor;
     if (use_numinterp)
         voxel_sampling(3) = voxel_sampling(3) ./ conf.num_interp;
+        if (strcmpi(conf.shape_function_type, 'w'))
+            voxel_sampling(1:2) = voxel_sampling(1:2) ./ conf.num_interp;
+        end
     end
     voxel_sampling = max(ceil(voxel_sampling), 5);