Like the ones used in models like: Mjölnir - UCAC5
I want to use it for steam from a coffee cup.
At the moment my settings are as follows:
1. A PNG with nothing but the painted and blured steam in white. You can download the file here. Remember that is white on a white background, so it would look like there's nothing in the image. I put a grey background just so you could see the steam, the image is below.
2. Transparency / Alpha Blending in the 3D settings/Materials, set at 98.
But obviously this is not right, as the steam does not show any gradients.
This is how the steam should look like: