Why does Grease Pencil ignore the particle system in Eevee? (2.82)

Question

I'm making a animation, combining grease pencil objects with 3D objects. This looks very cool. But there's one problem. Grease Pencil and the particles system don't play nice in Eevee.

This is an example:

A grease pencil object, a white blob, is placed between two 3D cubes. Then a 3D stylized conifer (a type of bush) is added.

So far, so good. The white blob is covered by the conifer. But then I add a particle system to the 3D conifer. And that's when it falls apart. Rendered in Eevee, the white blob (= Grease Pencil object) hides behind the 3D conifer, but appears above the generated leaves (particle system).

That this set-up can work, is demonstrated when I render it in Cycles:

Am I missing something here? Have I forgot to check a box or is this just a quirk of Eevee.

I use Blender 2.82 (on a Mac)

Hope somebody can shed some light on this matter.

Answer 1

I found the possible culprit of the problem and the solution:

In the material properties-tab of the material (in this case the leaves) I found the solution.

Because I used a png-file of the leaves with transparency I opted for the Alpha Blend. But somehow the 'backface Culling' was ticked. This was NOT a good idea. When unchecking the box it worked.

Although I got better results with the hashed option in the Blend mode.