How to offset toward the camera a billboard?

[Amerio.Stephane]

Hello,

For our runway lights, we have cluster meshes for the light models and billboards for the light halo. But each billboard is centered on the lightbulb (so it would be placed correctly whatever the angle we see the light from) and is 'clipped' by the mesh, making it obscured by the mesh, instead of showing in front of it. (the glass of the model has a rendering order set to -1)

Changing the Rendering order in the billboard (to +8) makes it worse: (the halo material is additive)

I tried to play with geometry inflation, soft interaction, etc., nothing makes the halo looks like it's "in front" (obscuring) the mesh. And there is no way to create a mgraph for billboards apparently, for example to add a camera z-offset to the billboard vertices.

Is this a lost cause?

Edited April 17 by Amerio.Stephane

[silent]

Hi Stephane,

If you will change rendering order of the billboard to -8 instead will it work better? It looks like the order is reversed for some reason for billboard material.

At least it works with simple alpha blend sphere + additive billboard:

If you can send us this part of the content -- we would double check (just a lamp + your billboard exported as a package), maybe there is a better options available.

Thank you!

[Amerio.Stephane]

I just tested with a new IG project, imported the AirportAssets package for the airfield_light object, and make a new world with just this object and a billboard. I modified the billboard material to have an additive preset, no shadows and disabled all light passes except ambient (so the billboard cant receive shadows).billboards_base_0.mat

Results: rendering order of billboard has no effect (Deferred checked or unchecked); 

What I need is more like this:

(this last image was made by disabling Depth Test, but this is not a viable option because lights halo should be obscured by other objects in front of it, like a closer ground light object or the cockpit, vegetation, or anything really)

Ideally, there would be something like a z-offset parameter to the billboard material so it would be moved along its normal.