I’ve been working on an A4 to complement the other locomotives I’ve been using in renders. It’s complete enough to start showing up centre stage now. The second phase of this project will start adding weathering to the materials system.
Hi @Markus-ipse - these are actually (meant to be) the steam escaping from the piston assembly. To be honest, I don’t think it is well motivated - I haven’t fully researched the details of this, but based it on other pictures that I’ve come across.
For steam in general - wherever it is coming from - I currently model the envelope by hand and then use procedural volume shaders (as well as a few layers of displacement to get the finer details). In this image, I’ve also kept the steam in a separate layer and then boosted the contrast a bit in compositing.