Heightmap distance field only works when there is another object that affects distance field.

I’m experimenting with landscapes right now, and I tried using heightmap for distance field. It did not work. After some more tweaking I noticed that it only works if there is another object in scene affecting field.
So now I wonder if it’s working as intended, or if I missed some option that turns on heightmaps distance field mesh, but then again, why does it work when there is another object? I’d love some clarification on that matter.

EDIT: It seems to be related to fact that I use projected grid shader on plane that I want to test distance from landscape on, but I have no idea why it does work this way.

EDIT2: Or not, I tested few things and it looks like it’s something wrong with mesh itself, even without projected grid shader.

My projected grid ocean plane, with same mesh with simple DistanceToNearestSurface/1000 -> Diffuse shader to the right.

Same scene after I add simple primitive cube.

thats because Landscape dont have distance field as far as i know you could combine it with the DepthFade node witch works for Landscape and SM !!

hoope this helped you