Transparent background doesn't seem to work.

First of all, thank you for a fantastic free tool <3

I thought "Transparent Background" meant that it would only render the model, with lighting, onto a transparent raw image, but it always includes the camera background.

This is the default demo scene (it's an HDRP-project, so the sprite shader doesn't work properly). Here, the camera's background is set to "Sky", but there isn't one, so it uses the default blue background color. When I flick the switch between "Use Transparent Background" and "Use Color Background", nothing changes, even if the background color is set to 0 alpha, and the camera's background color is also 0 alpha.

And when setting camera background to "None", there's this weird grey background with black lines on it. I switched out the prefab for my own 3D prefab with HDRP-materials.

Is there no way to get it to render JUST my prefab onto a transparent Raw Image?

[Super-Genius]

"Transparent Background" does work for modes that don't overwrite the alpha channel or support alpha channel. The rendering of the sprites is done in two passes, so the alpha must remain on the first pass.

For your first two images, the sprite not rendering correctly is a missing shader for some reason.

I believe that HDRP trashes the alpha channel (using it to calculate the HD lighting) during rendering, so probably why you are seeing black lines in the background.

I might be able to fix this by rendering the alpha channel separately, which I think I do and disable the postprocessing (which usually overwrites alpha). I thought I had done it that way, but I can check.

Though I used the PreviewGeneratorDefaultCamera prefab for the images above, I'm also seeing the following at the bottom of the PreviewCameraPostProcessing prefab. Of course, it has added its HD Camera Data component, but it is also missing a script. I just imported it from the Asset Store.

Oh, and we're using the newest Unity 2019 and HDRP + Core RP package versions.