Hey guys i have a problem.
If i apply a volumetric shader to my heart it just shows me cube and not the volume of the heart.
Could you guys explain me, why this happens and how to fix it? (btw the heart has all modifiers applied)
I would appreciate it.
Thanks 
That’s because Eevee can’t do volumetric meshes like that, it can only do cubes. However, there is a way to do it. You create a new empty volume object and use the mesh to volume modifier.
The result may be a bit boxy, so you can also use the volume displace modifier to break the shape a bit (just use a cloud texture and make sure to set it to color mode, as that’s what the modifier expects).