I'll concentrate on vehicles for GTA IV, but most of these tips work for other game textures such as pedestrians or signs, as well as other games like GTA SA, or vehicles in flight or truck simulators.
While I strive to be as accurate and informative as I can, I am by no means a professional artist. I'm a hobbyist, learning his way as he goes along, just like many of you. Feel free to add your suggestions and/or corrections.
Most images here have been scaled down and can be clicked to view in larger sizes. I'd also like to thank all the photographers and artists whose images appear in this tutorial. Without such visual aids, it would be much more difficult to teach.
I've covered many different aspects, each in its own lesson:
Lesson 1: Basics
Lesson 2: Layers
Lesson 3: Positioning & Reference Points
Lesson 4: Text & Fonts
Lesson 5: Normal Maps
Lesson 6: Optimizing a Simple Logo a: Colour Correction, b: Adding Realistic Detail
Lesson 7: Creating a Complex Logo From a Car Photo
Lesson 8: Creating Simulated Reflective Vinyl
Lesson 1: Basics
If you're completely new to modding GTA, I suggest you acquaint yourself with installing mods before you create your own skin.
Any Windows PC comes pre-installed with MS Paint, but I'm afraid it'll be too limited for what we need. Adobe Photoshop (PS) or Corel Paint Shop Pro are great, if you can afford them. But there are free alternatives that have nearly all of PS's functionality. paint.net http://www.getpaint.net/ is popular, but I haven't used it much. Since I'm familiar with The GIMP http://www.gimp.org/, I'll be referring to it throughout this tutorial. Regardless of which program you use, remember there is a wealth of great tutorials on the web, specific to each program.
If you haven't used any of these programs before, I'd try editing an existing texture first, before you make your own from scratch. Just be aware that if you change someone else's work and release it on the web, that most artists require their permission for you to do so, or at least that you credit them for their original work. Check the readme if one's included, or contact the artist if you're not sure. The last thing anyone wants to hear is "Mr. X stole a logo from Mr. Y's car. Mr. X is a thief! Mr. Y's a selfish jerk!". We don't need that drama, we're here to have fun.
GTA IV imports & exports textures in .png format so our final product will need to be saved as a .png. However, while we're editing, .png has its limitations. You'll likely want to save yourt work as you go along, before it's finished. I suggest you save your work in one the following file types:
-.psd for Photoshop,
-.xcf for GIMP,
-paint.net has an available plugin to read .psd files
This allows you to save your work while keeping information such as seperate layers. What are layers? I'll explain in our second lesson.
You've got a car downloaded, it came with skins already installed, and it likely came with a template. Since it's such a popular car, I'll use Bxbugs123's CVPI as an example:
Note that the above template is an example only, it's been scaled-down for easy viewing here. For best results, use the full-size one included with your downloaded car.
The template shows you reference to where the skin will be applied, but it is not intended to be included as a part of the skin. If you fill in the template itself with your desired colurs, text, etc., it will look poor. I'll asume that you want a quality skin, or you wouldn't be here. So, how do we utilize the template, 'painting' on top of it, and then getting rid of the template later? By using layers.
Lesson 2: Layers
"Layers? Sounds kinda technical, what about text, or stripes or something?" Text, stripes, logos, etc. are all best used in seperate layers. "GIMPtrick"'s video on YouTube does an excellent job of describing the "whats" and "hows" of layers, I have the "whys" for us below.
There's a few reasons to use layers. You can have the template on the lowermost layer (like the 'tabletop" in the video), and 'paint' the solid background colour on a middle layer, your stripes on an upper layer, and text on another layer. I go a step further, and make each stripe colour on its own layer. This way, there's no gaps or bleed-through with two or more adjoining stripes. just like the dots in the video. If we need to correct the position or colour of one stripe, we can do so without affecting the other layers.
I'm going to make a replica of the Ontario Provincial Police Crown Vic:
Russell County (Rockland) O.P.P. by smitty93, on Flickr
So, let's open our CVPI template with GIMP, and right away, save it as an .xcf file. Our main background colour is black, so let's make a new black layer.
Right-click on the background layer, create a new layer, and for simplicity, call it "black". GIMP will automatically select the newest layer for us to paint on, but if we needed to work on the another layer, we can click on it in the layers dialog, and edit on that layer.
"Whoa! Where'd the template go?"
Don't worry, we can hide it. Either completely, by clicking the little 'eyeball'... :
...or partially, by lowering its opacity (making it partly transparent), both found in the layers dialog:
We're now done with the black, so let's hide it completely, so we can see what we're doing. If you hide the template as well, you'll see the canvas is grey checkers, representing transparency. We'll need the template though, so let's leave it visible.
--Note regarding white backgrounds--
Some GTA IV vehicles support 'transparent' textures. They already have a white base, so no 'white' layer is needed. If you leave the skin's background transparent, you'll achieve a smaller file size, and a texture with slightly more detail that "pops" from the car, as if it were really decals. Most of Bxbug's cars require soild backgrounds, while LUXART's support transparency. If you're not sure if your car uses transparent textures, just paint the background solid white. You can tell whether or not by viewing the original textures in SparkIV. This example of LUXART's texture is transparent, notice the grey checkered background:
Let's make some more layers. The white paint, the stipes, logos, etc. will all be in seperate layers. Let's do the white paint next, by first creating a new "white" layer. We can verify that we're actually working on the "white" layer, and not the "black" or "template" because "white" is selected in the layers dialog. The roof's simple, it's all-white, so we'll draw a box and fill it with the bucket tool.
The front doors need a little more precision, so that we don't paint the rear doors as well. We'll lower the opacity of the while layer, to around 50%, so we can see both the white and the template. We'll zoom in and paint with the brush or the pencil, erase some if we need to, all the while not affecting the black layer, template layer, or any other layer. Here. I just need to finish painting along the left gap between the doors:
Repeat the process for each new colour, stripe, logo, etc. Creating text will automatically create a new layer as well. I'll give more tips on text & fonts in lesson 4.
Remember, you can keep saving your work as an .xcf or .psd as you work. When you've finished, you'll need to save it as a .png., which doesn't allow multiple layers. GIMP will ask you if you'd like to merge the layers, or you can do so yourself before hand. Right-click on each layer in the layers dialog, and select "merge down". You can now delete the template layer also. Don't worry, If you need to change something later, you still have the .xcf copy in all its layers.
Lesson 3: Positioning & Reference Points
How do you know where to put details like logos, text, & stripes, or what size they should be? We can use a photo as a layer, and use it like we would use tracing paper. It should be noted that we are NOT using the photo as part of our final texture. We are using it for reference only. Think of it as using a projector on a white wall, projecting a photo on the wall, and painting what we see in the image. When we're done, we'd turn off the projector, or in this case, toggle the layer off or delete it.
Since the above reference photo is a nice side-shot, let's save it, and drag it into our texture in GIMP.
The photo is now its own new layer. We'll get rid of the excess background by placing a box around the edges of the car and selecting "crop to selection" from the Layer menu. (selecting "crop to selection" from the Image menu will crop the entire image, we don't want to do that). We'll resize it so that it's roughly the same size as the car in the template.
Edited by lonestranger, 12 March 2012 - 08:17 PM.