Hi, everybody! I’ve started work on a video series which will feature many vehicles, and as such I’m developing shaders that can (hopefully) more or less be thrown onto a variety of meshes and still look decent. Since the tires are such a visible component of vehicles, I’m putting extra time into their materials. Ultimately, I need several kinds (clean, slightly dirty/worn, very dirty, etc), but for now I’m mostly just focusing on an average, run of the mill tire shader.
I’m also trying to start as simply as possible, to keep the nodes easy to understand and hopefully making problems easy to diagnose. Here is my first quick go at it.
Referring back to the basic rubber material, does anybody know how to create the look of oil on the tire? I mean the colorful reflections, similar to how an oily puddle has many colors in it? I’ll post a reference image if I can find one.
With cycles there isnt much need for RGB to BW… just plug the colour straight through and it will work exactly the same.
your glossy roughness is super high aswell (looks to me about 0.7 to 1…)… could lead to fireflies… i rarely use anything above 0.3 or 0.4 for glossy roughness… anything higher then that can cause fireflys and it usually is better just to fake it using fresnel, then to use super high roughness values.
other then that up the top you are adding two colours together, which later on you are using as a value… it probably would be more efficient to use math nodes there instead of a mix shader.
one final note, try not to cross your noodles… it makes working through your node network unnecessarily complicated.
I’m surprised you’re not using an anisotropic shader somewhere in the mix. I’ve done some quick shaders for tires (just a rubbery look, but not textured or dirty like this one), and I’ve found that it gives a better result for the more-diffuse (rough) reflection along with a regular glossy on top for a more tight reflection. If setup right it spreads the soft highlight along the direction of curve where the sidewall bulges out. Of course how well it works may depend on the mapping used too. Perhaps give it a shot and see how well it works in your setup.
From my experience the quality/look of tire shaders depends a lot on the lighting. Now, I am not sure if this is really the case? or if a realistic material would have no problems (my shaders are far from perfect).
This probably doesn’t help you too much, if at all, but just my thoughts/experiences on the matter. Whats your take on it?
Sorry for the late reply, ctdabomb! Yes, I tend to agree with you on that point. PBR materials supposedly help a lot with this problem, but of course I’m not using PBR here. And even in real life, some things look great under certain lighting conditions and not so great under others.
Ideally, it’s probably best to design your shaders under the specific types of lighting you’ll be using in the finished project (if you’re able to).
Just following up, to show what I mentioned earlier. Mats being both the same, except for anisotropic in the mix for where the spread out reflection is. This is a cheap quick & dirty procedural material, but you can see the subtle difference it makes on the tread on the top of the tire. The sidewall is a little off though, because the anisotropic rotation isn’t correct in regards to how the rubber would have its ply-bias. However if you have the patience to UV-map your tires, you can paint a grayscale map to control that rotation and the effect is much better. Molded rubber like this does have a directionality that spreads out the highlight.
