Headlight/tailight texture

rares

Hy guys! i have a game vehicle that i have to texture, and there isn't any geometry left in the budget to create the actual headlights or tailights, so i have to "paint" the on the plastic covers. My questions are :
- what would be a good workflow to get a convincing result ?
- what's the best way to simulate in photoshop those patterns that the plastic headlight/taillight cover have ?
i'm thankfull for any ideeas

3Drobbo

hey, post up a picture of your car, so we can see what we have to work with. If its a real life care, how about photo textures?

like this:http://www.smcars.net/forums/attachments/work-progress-video-game-real-time/93936d1242924934-my-low-poly-real-time-no-lights-3d-flash-cars-suprastreetracing.jpg

Ultimatley once wesee ur car we can see if it would be a better idea to remove some polies from the body to be able to add the light geometry. even it it is basic like this :
http://xboxoz360.files.wordpress.com/2009/09/forza-3-oxcgn-434.jpg

Xoliul

To paint realistic, convincing light textures from scratch is really difficult. You're painting combined reflections and refractions in a 2D surface, it's tough to get your head around.
The easiest thing is to get a good, head-on highres photograph, but if that's not available all you can do is study photo's and try to recreate the effect as good as possible.
If you want i can show some examples of how i do this.

rares

@3DRobo, the car's an opel Calibra, haven't found any pics from wich i can "steal" some good textures
the lights
front http://www.valmet-automotive.com/automotive/images.nsf/files/b5027552422d88c7c225713700566f62/$file/calibra_w500.jpg
back http://neodesign.eu/neo/photo/OpelCalibraRearPHANT450.jpg

my model :
texture wip : http://i111.photobucket.com/albums/n146/rareseu/texWip.jpg
wires :[url] http://i111.photobucket.com/albums/n146/rareseu/wires.jpg[/url]

@Xoliul : yes i'd really like to see some examples of your workflow

Chunkey

To be honest I'd would optimise the car geometry some more as I see wasted polys, good example where the front number plate is, the edgeloop running up from the middle of the front arches, which then terminates at the bonnet where it seems you've collapsed 2 edgeloops already.

This is just an example, plus is the limit set in stone for a technical reason?

Usually poly limits are only a guide in my experience and can be bent slightly if need be

rares

@Chunky: im sorry i can't figure out what edgeloop you're talking of, can you highlight it on my screenshots ? the poly limit is set in stone here, and i have reached the limit

Chunkey

Very quickly done, probably more places that could do with optimising- main aim is just to take off verts that are not going to be seen and are not pushing the shapes of the car and pumping them in to areas that will make a visual impact.

Overal it's a nice model, just needs as bit of tidying up

Sage

well if you can't steal the texture from picture you can always model a 3d version and bake that down to your texture. You will probably have to do some painting over in Photoshop to get it to fit your texture.

rares

I see what you mean Chunkey, you are right those should be removed
@Sage: i tried modelling some basic shapes for the lights and baking the AO onto the plastic covers, but that didn't give any usable results, did you have in mind a different procedure ? please let me know if so

Xoliul

Rares:
here's some tips from me:

First one I ever did was a Porsche 959 taillight, couldn't find any good picture for a texture back then. Here's a crop from the sheet:



You need to FULLY understand how the light is built, because you should paint it up in layers. I started this one by first painting a flat representaion of the chrome light fixtures underneath the glass, in grayscale. You can tell that the blurry reflections suggest a sphere or hollow fixture underneath. When painting these parts remember reflecting up = sky/light, reflecting down = ground/dark. Also try to suggest tiny microbevels underneath the glass with 1 px shading.
On top of the metal fixtures, there's the glass covers. These should start as solid colored layers, put on multiply and perhaps reduced in opacity. I gave all of them a lighter gradient from the top, to suggest light reflecting slightly. I put some 1 px bevels around them to suggest thickness (these could be better, but this texture is 3-4 years old now).
A very tricky part, is if the glass covers have some sort of inside pattern that refracts the light strangely. I did these by using pattern fill layers with small pixel-detail black and white patterns. Subtletity is key here, and for me this was the hardest part. The orange indicator in the left bottom corner has a lot of this and I think it didn't come out as well.

This method is if you're doing it diffuse only onto a flat plane. For clear headlights, with big round lenses behind them, I would model them anyway. You can only get away with so much in the textures before it looks strange (the headlights of that lowpoly Supra 3DRobbo posted is an example of trying to do too much in texture IMO). I think you can get away with doing the inside of headlights with only 200-250 extra tri's.

A more next-gen example is my fictional Cougar SS car (hence no phototextures );



The rearlight is way more complex obviously. Headlights is just modeled and normalmapped geometry with a clear cover. The chrome shader helps sell the effect a lot.
Rearlights are simple in geometry, but I actually modeled a really complex taillight in highpoly, to bake to normalmap. I'm still a little disapointed those "wires/lines" aren't completely straight on my unwrap, but I don't think it could be avoided. Note that the diffuse is red as well, even though this would be white chrome in real life; I couldn't get the colors convincingly otherwise. With a clear red cover it still didn't look good enough, so I handpainted the colors for the glass cover, which is the rightmost bit of texture. Highlights were painted in (note the warm specular tones, not just white) and I added some fake refraction effects with pattern fill layers. Choosing and painting the colors for the glass cover was the hardest part here. A lot of tints were used, red, yellow, purple, orange.

I hope this helps you! I might even turn this into a small article for my website...

Sage

try and find good enough reference. then think about what the materials are made of. model the large shapes and go from there. Think about how a flash light is built. It has a chamber inside that is covered by that clear plastic or colored plastic. The plastic cover usually has some pattern on it. You might have to light the scene as well. If I can's find what I'm looking for I also use lights of other cars that look similar and make the texture that way. I build it up in layers.

rares

@Xoliul : thanks man your tutorial really helpes me with the problem
@Sage : i understand how to model the headlight, but what do i bake onto glass cover?

Sage

you bake the diffuse. you set up a material so it has the reflections, shadows, chrome effects, refraction of the glass(plastic) and the bump. You might have to do it in layers and then put it together in Photoshop.

I'm not sure how many maps you are planning to use, if it's just a diffuse, light up your head light as close as possible to how you are painting your light source.

Eric Chadwick

A 3d headlight tut

Sage

I was looking at headlights today, all the way to work and on the way back... LOL I stared at my mothers car for a little bit, looked at the neighbors car and noticed that the pattern at least for the back lights are very similar, it seems to be small squares on the red section, the where there is clear plastic long rectangular shapes. These seem to follow the curves of the headlight, but that was different depending on the car.

I thought a shellac material might give your what you need. The inside of the material would have a bump and you can go as far as adding an opacity map to that. Anyway play with that.