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GMWC Modular Car Template Tutorial
A Note About Image Editing Software
Photoshop, Alpha-Channels and the .PNG Format
Creating Your Personal Template
Using the Opacity Slider
Using a Grayscale Image to manipulate the Alpha-Channel (Coming Soon)
About This Tutorial:
This tutorial is intended to help you better utilize the skin template for the GMWC Modular Car. While it has been written specifically for the GMWC template, the ideas and concepts presented can easily be used when developing a custom skin for other models.
A Note About Image Editing Software:
This tutorial was written with the assumption that Photoshop will be used to edit the image. The techniques set forth can be used with other image editing software, though the individual steps may vary slightly.
Photoshop, Alpha-Channels and the .PNG Format:
The Alpha-Channel of an image is used by rFactor to determine how shiny and object appears in-game. The GMWC Modular Car models have a slightly higher than normal default reflectivity. This is to facilitate custom reflection effects that a skin author may want to incorporate in their designs. This means an image with an unadjusted Alpha Channel will be extremely reflective. Even if all someone wants is a standard glossy paint job, the Alpha-Channel will need some adjusting.
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| Example of car with un-adjusted alpha-channel | Example of car with properly adjusted alpha-channel |
The Alpha-Channel is used by photoshop to determine how transparent an image appears. Within Photoshop there are two ways to manipulate the Alpha-Channel. Indirectly, using the image's opacity slider, and directly by creating a grayscale image in the Alpha-Channel - we'll discuss each method in more detail later in the tutorial.
GMWC requires skin submission in the .PNG format. While the .PNG format supports the Alpha-Channel, Photoshop's implementation has been "broken" since about Potoshop 5. Photoshop only supporst manipulating the Alpha-Channel through adjusting an images opacity slider. If you try to mainpulate the Alpha-Channel directly with a grayscale image, when you save the file as a .PNG, the Alpha Channel is lost. There is a freeplugin for Photoshop that adds support for some of the additional features a .PNG file is supposed to have. That plugin is called SuperPNG. Please note, the current version of the SuperPNG has taken Adobe's route in implementing a .PNG file's Alpha Channel. However, older versions of the plugin will support using a grayscale image to manipulate a .PNG file's Alpha-Channel directly. That plugin, and it's installation instructions is included in the template file, and can also be found here.
About the Template:
The GMWC Modular Car Template can be considered a template of templates. Each individual, skinable component of the modular car has it's own section containing multiple layers. In Photoshop, those sections have been organized into groups or folders. As some graphics applications may not show the groups used by Photoshop, the layers have been named in a way that makes it easy to identify which section they belong to.
Each section corresponds to an individual component of the modular car. Which sections you use will be determined by which components you, or your team owner, chose when designing your car.
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| Layers shown in groups (Photoshop) | Layers shown ungrouped (Gimp). Note: the portion of the layer name after the hyphen identifies the section |
Creating Your Personal Template:
For this tutorial, I'll be creating a skin for a car that uses the following driver skinnable components: B-Nosebody, A-Sidepod, A-Wings and C-Induction.
The first step is to open the template in your image editor of choice. Hopefully one that supports layers.
Next, since I won't be changing the driver's suit or helmet skins, and I don't want to be distracted by that part of the template, I'll make them "invisible". Do not delete those sections though, if you do, you're driver and helmet won't look right.
Next I delete those sections I won't be using. Note, I'm deleting the entire Roll Bar group since the roll bar I've chosen to use is not driver skinnable.
After deleting the unused groups, I merge similar layers together. All the label layers together, all the grid layers together, all the mask layers together, etc. I do not merge any layers from the driver suit or helmet. I also delete any of the section groups (other than the helmet and suit groups), and rename the layers, eliminating the section group reference. I now have six layers, Labels, Grid, Mask, Details, Shadows and Paint - keep the layers in that order, and set the shadows layer to "multiply".
I also have two remaining groups, helmet and driver.
Finally by saving the file, I'll have a template that's personalized to my specific combination of parts. Team Owners: You may want to do this yourself once you've finished desgining your car. You can then post the template on your team page so your team members can have a personalized template without having to create it themselves.
Adjusting the Alpha Channel:
As I stated before, there are two methods for adjusting an image's Alpha-Channel. I'll cover adjusting the opacity slider first, followed by manipulating the channel directly with a grayscale image.
Using the Opacity Slider:
First, let's assume we have our skin layed out, looking like we want it. In this case, I have a black paint job, white rims, a silver racing stripe going up the nose and the number 14 on the sidepods in white. I'm also sticking with the default blue driver's suit and helmet. I've deleted unused layers and merged remaining layers until I have only the essentials left. Since I plan on setting a different reflectivity level on the stripe, numbers, base paint color, and rims, I haven't merged those layers together. I've also kept the helmet and the driver suit as seperate layers. The details layer has been merged to the paint layer, and the shadows layer has been eliminated, since the shadows won't show up that well against a black car. I've also used the magic-wand tool to select the painted areas of each layer and used that as a mask to delete anything in the lower layers that might show through when I adjust each layer's opacity.
In rFactor, the more opaque an image is, the more reflective the surface. The closer to transparent, the more matte the surface. However, you cannot set the opacity slider all the way to 0%. If you do, that item simply becomes invisible and won't show up at all in game. So the minimum opacity setting you can use is 1%
Even though black paint is very reflective, it's nowhere near as reflective as it would be if I left that part of the alpha channel unchanged. So I select the paint layer, and using the opacity slider I adjust the apacity to about 55%
Since white paint isn't nearly as reflective as black, And decals are often less reflective than the surrounding paint, I set the opacity of the numbers to 5%.
The rims are also white, but I like to think of them as being powder-coated rather than painted. A poder coat, even in white, will be a little more reflective than the white number decals. So they're set to 20%
I want the silver strip to look like one of those reflective metalic decals, so I chose a really light gray for the strip color and I leave that layer's opacity at 100 %
The helmet is almost as reflective as the black paint, but not quite...40%.
And unless I want the driver to look like he's been dipped in shelac, I set the driver's suite to the lowest setting I can...1%
And here's what I get.
I save this as a .PNG and submit it to the league...let's see the results.
Not bad! The black paint could probably use a little less shine, and the stripe looks a little too white, but not too bad.