World Position Behind Translucent Surface

hi .
how can i get world position in translucent material? world position behind the translucent pixel which being rendered. just like “worldPosition” in post-process;
i have tried “WorldPositionBehindTranslucency” but it give different value Compared with what “َWorldPosition” give in post-process.

i saw ‘PostProcessMaterialShaders.usf’ that calculates the world position from depth buffer, then i wrote the following code as a custom expression but it doesn’t work.

	float SceneDepth = CalcSceneDepth(ScreenAlignedPosition(Parameters.ScreenPosition).xy);
	float3 ScreenVector = mul(float4(Parameters.ScreenPosition.xy, 1, 0), View.ScreenToWorld).xyz;
	return  ScreenVector * SceneDepth  -;