Suggestions for specific procedural metal material?


Long time reader, first-time poster. I’ve been working on a model of an EMD Locomotive for some time now and I have not been able to find a solution for recreating this warped/bent metal look that a lot of the panels seem to have on locomotive and railcars. Any suggestions or thoughts?

Here is an example:

If you look at the specular and reflective highlights you can see contours showing that the metal panel/shell of the locomotive is not completely flat but instead warped/bowed outwards in somewhat random places.

I’ve tried using a cloud texture with a displacement modifier but the effect doesn’t seem to match what we see here. I’m almost wondering if maybe I should make use of vertex painting so that parts of the locomotive that would have structural support behind the panels would not be affected by the displacement modifier… Any and all suggestions would be truly appreciated!

I’d start with some low frequency noise as bump map. Yes, you can of course use displacement which will avoid any shading errors due to reflection rays being bend inside the surface (can be avoided if you allow some inaccuracy in the render - less bumps at grazing angles). But to me, using displacement sounds way too expensive for something like this. But I like the idea having a mask where this bump/displacement is less pronounced (not eliminated though).

And yes, this “human hands are involved” look that makes it less perfect, is extremely important imo.

Show us where you are now, and maybe share a couple of panels and lighting setup and it may be easier to help or experiment on. These cases are rarely a case of “one solution fits all”.