Can a glass plate act like a lens? I am trying to implement rough dielectrics on my renderer. I compared the results of my renderer and Mitsuba renderer. However, a thin glass plate which is a cube scaled by (0.4, 0.4, 0.01) magnifies the object in front of it in Mitsuba while it does not magnify in my renderer. Do I miss something or does Mitsuba renderer do something wrong?

edit: IOR of glass is 1.1 and outside is air.

Result of my renderer:


Result of mitsuba:
The box.obj file has no vertex normals, and by default Mitsuba will generate smooth normals for OBJ files that don't specify their own normals. This creates the magnification effect: the box with smooth normals forms a convex lens!

By adding this line to the box object in the scene file:

&lt;boolean name="faceNormals" value="true"/&gt;


I got results that look equivalent to yours: