Headlights - Page 2
Again, I have to admit... headlights to me are tough. After a long period of researching how I wanted them to work, this was what I came up with... Take these ideas and improve upon them if you can.
The key areas to the success of this headlight method is the lens texture... (even moreso than the light we'll add in the next page).
The first requirement of the lens (and the point of the first portion of this material) is that which will uphold the 'aesthetic' value. It will try to look like the actual headlight itself. The second part, the transparency, which we will get to later, will be for adding more control to the emission of the light.
For now, I have made a texture map that will be useful for aesthetic value.
This is the map in question... I made this in an attempt to replicate the ribbed nature of the headlight glass. It does a pretty good job but the next time I make a map like this, those gridlines will be lighter and less conspicuous. But for now, I was satisfied enough to leave it as is!
The material I made uses the following channels- transparency, bump, reflection, glow, and for some reason the color channel. (I can't remember why, but it's working, so I won't change it!) I suppose the specular channel is a good one to use too...
I've used a copy of the map I made in the bump channel at about 25% strength. Although, I have found it looked good even right up to about 75% strength... give it a whirl, whatever you like.
Reflection (not shown)
Just for the sake of increasing the glossiness of the glass, I added a bit of reflection... you'll want to test it a bit yourself to find if it helps your material.
The glow is enabled for the light lens texture when the headlight is supposed to appear turned 'on'. When the light is 'off', disable the glow... Anyway, the glow settings establish a yellowish tinge, with a small radius. The inner strength is higher so that the glow is more of a glare in the middle of the lens rather than an aura extending from the outer edges (which looks wrong to me...)
Specular (not shown)
The specular will mainly be an issue when the light appears to be off (otherwise the glow will hide any specular you're likely to see). If you want, do a few test renders with the light 'off' until the glass specular looks correct...
The transparency channel uses a simple gradient shader in the texture slot. The gradient shader is a radial one, between black and white/light grey... I put it at 100% mix strength, in the multiply mode...
I also added a little fresnel effect for the refractive look.
Set this material to flat projection right in front of the outer lens object. Make sure it is not tiled, and is about the same width and height as the dimensions of the lens object.
This effectively makes the texture a decal that should cover the object just about perfectly.
A quick render shows the texture to look at least a little like a headlight. (This render shows the material with the glow off. The glow on really needs the light in place to help out, and the light comes in the next page, so we'll look at it like this for now!)
Okay, now a little background on the reason for using the gradient in the transparency channel. When I first cast a light through the primary texture map (the ribbed one), I was happy with the look of the headlight glass, but I could not control the appearance of the light being cast upon the ground plane. Now, I should mention, I wasn't interested in producing a headlight with the cheesy volumetric light beam like you only seem to see in comic books... I just wanted a light that looked like the effect you get on a dark night... the headlights illuminate a specific area, but the aren't overdone... However (and this is my point, finally), I couldn't do this with the first map... with that map, I got big wide illuminated areas on the groundplane that picked up the shadows from the ribs all the way to the edges... the effect sucked... looked like hard light coming out of a prison cell...
But with a simple gradient, I could control the 'falloff' of the edge of the light beams that hit the ground. This texture I did with a simple stock Cinema radial gradient shader so everyone could try it... but my advice would be to use a Smells Like Almonds gradient so you could control it much much better...
This is just a closer look at my gradient.
This shader is in every copy of Cinema that I know of... but I would really recommend you use a BhodiNUT SLA gradient... you could control the light passing through this lens SOOOO much more accurately.
Now, the best way to determine how successful all of this was, is to put the light in the chamber, turn on the glow and see how it turns out.
Ah, jeez, I hope you like it! (But tweaks are up to you!!!)
The color channel isn't vital to the effect of this material, but I included it to add just a tiny little bit of visible definition to the gridlines or ribs in the texture map. Almost no 'color' produced by the sliders (note the brightness at 5%), and the texture map in at a mere 25%, or less if you'd like...
Luminance (not shown)
The luminance is even less vital... I used 5% luminance color brightness (default white, i.e. RGB all at 100%), and the map mixed in at less than 15%.