Having been trying my old tricks of Aluminum tape, I have not yet been able to get a result where I felt like I nailed the effect I was wanting. So, I have spent a couple days seeing if I could find another way. Finally got a spark in the proverbial light bulb: texture mapping.
I found a photo from a similar car (which I can't post here, due to copyright), and Photoshopped it into this:
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fburlrice.com%2F_LS_MiniHyCube%2FPS_oilcan.jpg&hash=30f92b1e17e2422fe2c7db55fde598b15ca67aef)
From there, some black magic takes place to create a mesh in Fusion 360. This goes through some smoothing & polygon reduction. When I'm happy with it, I finish off the object by making it a solid, with a flat back. Now, I have something I can upload to Shapeways:
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fburlrice.com%2F_LS_MiniHyCube%2Foilcan3.jpg&hash=8022754cb67cf10f8f4e50b4c754bd7387f79ed0)
With some basic manipulation, I'm hoping I can print 3-4 copies of it, all slightly different. This should give me enough variety to do a whole car side, with no obvious repetition.
Forgot to mention, this also solves a couple other problems I've been working on for a long time:
1) I can see whether the edges will be even between panels beforehand now. This means less (maybe zero) filling and sanding, which makes the weld bead decals easier to apply.
2) The valley can descend into the negative z-axis (relative to the weld bead). Before, I had to exaggerate the peaks to make the vallies appear.
Cool!
Does this mean you can model the damage to the roof caused by an over eager forklift driver?
Lawton: possibly. The key is starting with a well lit image, since the software only interpolates the z-coordinate based on relative light/dark. For instance, I had to find a photo with no reporting marks to do the example above.