Custom Alpha Channel Tutorial for Gimp (advanced skinners)

[WWGreyWolfe]

Salute All,

I'm using Adobe CS3 and would very much like to edit my alpha to mate the painted areas and shine up the Alum. I have made some tries at this with the worst out come . I tried to copy my paint and marking to my alpha but im finding invisible holes in my AC in game, small but I see it. Not sure if im needing to convert to shadow before I paste to alpha. Any help would be great.

 

Salute Wolfe

[pjmack11377]

Great info.  Thank you so much.

[Megalax]

I've tried this with Gimp 2.10...and it doesnt seem to work as the OP describes.

 

A work around I've found is to keep the Alpha channel I want to use as a layer in my template, then I finish my skin and use copy visible (shft+trl+C) and paste as new (shft+ctrl+V), then I copy the alpha layer into the new file as a layer mask. Save as .dds and presto! 

[adler_1]

hello

can you please show us how to do this with PS 6 . or where to go to which explains how to .

[6./ZG26_5tuka]

57 minutes ago, dog1 said:

hello

can you please show us how to do this with PS 6 . or where to go to which explains how to .

Since I don't have PS6 I can't.

On 1/3/2019 at 9:08 PM, Megalax said:

I've tried this with Gimp 2.10...and it doesnt seem to work as the OP describes.

 

A work around I've found is to keep the Alpha channel I want to use as a layer in my template, then I finish my skin and use copy visible (shft+trl+C) and paste as new (shft+ctrl+V), then I copy the alpha layer into the new file as a layer mask. Save as .dds and presto! 

Late reply, but important: The Tutorial is based on version 2.8. I'm not aware hat issue you ran into and if this is caused by the newer version. If so I will of course update the intial post.

[Jade_Monkey]

The versions above 2.10.2 seem to have an issue. It took me a while to figure it out but going back to 2.10.2 solved it.

 

Anyone willing to show how to create bump maps for IL2?

[Hanu]

It looks like Gimp 2.10.10 is unusable if you apply the alpha channel. The skin is very very dark and "Oily". I went back to 2.10.8 and skin was fine again. It is really sad as 2.10.10 handles multiple layers much faster now.

 

It looks the same in both versions on desktop, but I wonder if the problem is in compatibility with dds.exe plugin which has not been updated since 2013?

 

Has anyone else noted this, or found a workaround for this issue? I've been using it like "Merge visible layers -> discard invisible layers" -> "Add layer mask -> Channel, Alpha Channel", Export as DDS, DXT5, Generate mipmaps, Filter -> Box.

 

Preview in the spoiler as example is skin with historical markings

 

Spoiler

 

Edited May 20, 2019 by Hanu
Added spoiler tip

[Snacko]

Thanks to Stuka and Stick for their helpful guides.

 

I was using Gimp 2.8.18 and had some things that didn't work as stated.  I figured ways around them, and also updated Gimp.  Doing that and using these guides helped tremendously!!

 

 

[Snacko]

Dammit!  Today I had some time, so I thought I would fix the shiny surface on my skins.

 

I'm doing the same thing I did the other day, that worked.  But today, the Curves window has no affect on the Alpha layer.  I can drag the curve all the way down, and the layer image does not change.  I've tried it several different ways.  Any help is appreciated, or is Gimp just fickle?

 

EDIT:

Yes, Gimp is Fickle!!  I closed Gimp and waited a while.. Then tried again and it worked.  I just did the same thing as before that didn't work.  But this time the magic happened, I could adjust the curves and darken the layer.  ?

Edited September 8, 2019 by DDSnacko

[J2_Jakob]

3 hours ago, DDSnacko said:

Yes, Gimp is Fickle!!  I closed Gimp and waited a while.. Then tried again and it worked.  I just did the same thing as before that didn't work.  But this time the magic happened, I could adjust the curves and darken the layer.  ?

 

I don't know, perhaps GIMP is playing tricks on you, but once I figured out how to do it, it does work reliably.

 

short description of my actions (GIMP 2.10.12), when I want to tone down the gloss:
- drag the Alpha channel from Channels to layers (thus make a new Layer out of it), put it on top, make it visible. Everything should appear in shades of grey.

- Apply Curves adjustments - image should appear darker

- now drag this darkened layer back to channels and make it invisible in Layers (or delete it)

- flatten image, add layer mask, initialize it on newly created darker alpha channel
- export as usual

Edited September 8, 2019 by J2_Jakob

[Snacko]

I'm using the latest version of GIMP and am able to get it to work reliably now.  Thanks for the reply.  Doing this skinning has gotten me to learn a lot more about how Gimp works with the paths and selections.

[adler_1]

hello ,

When creating a new layer  and placing the alpha floated file it wont fit into the created layer but settles above , then when i anchor it deletes the file . ?!  It worked perfectly well the first time and i got my skin with shine . then when repeating it stopped doing so , selecting anchor or tapping outside deletes the float . i reinstalled GIMP . same result . I flattened before saving a copy the first time so now i need to make a fresh copy with the working layers . 

Edited November 11, 2019 by dog1

[adler_1]

image 2  you see the created layer below the alpha floated file , it wont go to the created layer . then if i anchor it deletes it . 

Edited November 11, 2019 by dog1

[pjmack11377]

 

This might clarify things.  Also, he has other videos.  Good luck

Also,  When you ancor the layer does just the float dissapear or the whole file?  If it's just the anchor layer then it's working.

 

Patrick

[adler_1]

when i place the floated  layer as you can see in image 1 it stays there till i anchor it and it deletes , nothing left . If i place a new layer as per tutorial and press CTRLV  it will place the float above  , not into the layer as per tutorial .  see image 2 . i tried these 2 methods .  the video is off no help in this case unfortunately .

Edited November 11, 2019 by dog1

[pjmack11377]

It's a problem that I have come across as well.  I am sorry but I am more partial to Photoshop.  Did you check out the authors other videos.  Perhaps someone else here can help.

 

Patrick

[adler_1]

i have PS6 , if you know how to go about it i'd be most grateful . i moved from GIMP tp PS6 3 years ago and i installed GIMP yesterday to follow the above tutorial  because of the shine issue for my new  P51 D  skins .  

[pjmack11377]

Im on PS 6 as well.  What layer do you want to add?

Are you trying to add an alpha 1 to the model?  If so you must firsl flatten the image in gimp, then add a layer mask (alpha  1) then export from gimp as a dds.

[adler_1]

ok hold on there are developments , i just had lunch and a break .I resolved the issue with GIMP i think , i'm going to do now one of my skins see what the result is  and i will post back soon . I resolved the issue by CTRL C then create a new layer and then CTRL V to create the float above ,then you right click and add to new layer . It worked , i have a polished skin on my viewer . will be back soon with positive result and image i hope .

Edited November 11, 2019 by dog1

[pjmack11377]

You are C copying and V pasting.  Let me know how it turns out.  Post a pic.

 

All the best,

 

Patrick

[adler_1]

here she is !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  i be will adjusting the shine later  . Phew what a drama  !!!!!!!! 

[adler_1]

how to reduce the glare or shine ? i am using the black white bar only and i'm down to 15 but there is no reaction . what am i doing wrong ? 

Edited November 11, 2019 by dog1

[Johann262]

On 3/2/2016 at 4:35 PM, VBF-12_Stick-95 said:

If you are reading this you want to know how to change the Alpha Channel to control the finish of an aircraft. 5tuka's steps above are excellent and allow for more detailed control of the finish of various parts of an aircraft than I am presenting here. I thought I would consolidate my methods which are spread out over a few posts and add a few things I have learned. My steps are more quick and dirty.

 

Some surfaces are meant to be more reflective than others, for example metal and wood. I find that generally these are already accounted for in the template's Alpha channel. Therefore all that is needed in most cases is a reduction of the lighter portions of the Alpha Channel proportionately across the boards to achieve satin and/or semi-matte finishes.

 

Using GIMP the following are the steps of adjusting the Alpha Channel that I use.

 

You will need to have the Layers open with the Channels tab also like this:

 

 

Go to the Channels tab. At the bottom of the Channels tab there is an Alpha1 channel. Drag this over to the image and drop it. This should turn the entire image gray. There is no need to deselect other channels.

 

This creates a new layer (not channel) in the Layers tab called Alpha1 Copy. It should be at the top of the Layers tab. You can deselect the visibility (eyeball) to see that nothing has changed in the other layers. I usually move this layer down to the Paint In Here section of the template but it probably doesn't matter.

 

Now make sure the Alpha1 Copy layer is selected and visible. From the menu go to Colors and click on Curves. You will see a box with a line going from the bottom left corner to the top right corner. The bottom of the box represents the darker portions of the image and the top the lighter portions.

 

Click and drag the upper right hand line down about 2 to 3 blocks. The further down the more matte the result. Then click the line one block over from the lower left and bring the line back up to one block. This preserves the darkest elements of the skin keeping them visible. Click OK to finish.

 

Here are images of the Curves screens.

 

 

 

 

Now deselect the Alpha1 Copy visibility. Drag it to the Channels tab, placing it just above the Alpha1 channel at the bottom. (This is a copy and not a move.) Double check that the eyeball is deselected. You just created a new Alpha channel. Leave the original Alpha1 channel there, you may need it.

 

Now go ahead with the normal process for creating the skin dds. Make sure when you add the layer mask that it is the Aplha1 Copy that you adjusted. If you don't like the result, either tweak it in Layers and drag it to Channels tab again (or delete the channel and layer and do another, it's pretty quick).

 

For some reason GIMP would not allow me to follow the copy and paste steps laid out in 5tuka's instructions even though we had the same version, albeit different language. I found the drag and drop just by accident.

 

Just an aside. Although much of the VVS paint was “matte”, lacquer was applied in many instances to protect the paint and decrease drag. This of course would wear with time. So, although the default Alpha1 channel with its wet look is incorrect, IMHO a total matte plane may also be. I think the truth lies somewhere in between. If you still want a total matte aircraft, just don't add a layer mask at all.

 

I hope this is helpful.

 

Cheers!

Hello, Stick-95!

I was really happy to run across this post, as I'm desperately trying to get my plane to not look like it's covered in a layer of water. Everyone works fine up until I try to adjust the curves values: nothing happens. I have only the alpha 1 copy selected, I have the window open and even preview is selected. Still no change to the image even after selecting OK. I am using the most updated version of GIMP and I understand your post is from many years ago, but might you or anyone have some advice to get past this hurdle?

 

 

Edit mere minutes later: Ok, so I went out on a limb and tried just making a black layer over the alpha 1 copy, changing the opacity to about 73, then merged it down to the alpha 1 copy. From there I continued with your instructions, exported it, and tested it out in Viewer. Finally, success! I still have tweaking to do, but I'm finally where I need to be! Thank you so much for your additional steps to this tutorial. And thank you to 5tuka for the tutorial itself!

Edited February 27, 2020 by Johann262

[J2_Jakob]

Hi skinners,

 

this is a little Python script I've just made. All it does is the boring stuff we need to do everytime we make changes to skins. It flattens the image, adds mask based on the (custom) alpha channel and exports to DDS format with pre-defined settings. It will prompt only for the resulting filename that the user has to input. The default value is J2_test.dds.

 

Pre-requisites:
GIMP with Python support installed

 

How to install the plug-in:
First we need to tell GIMP where to look for such scripts. (Edit -> Preferences -> Folders -> Plug-ins -> add a folder, or use existing)
I have created a folder C:\Users\jcb\.gimp\scripts.
Make a new file in this folder and name it make_DDS.py. (Maybe the name itself does not matter, I'm not sure.)
Copy the code in the end of this post and paste it into the make_DDS.py file.
!!! Make corrections to the file based on your environment !!!
 = adjust the path variable to suit your needs - this is where it will try to export your DDS. This folder must exist prior exporting. (Keep in mind the double backslashes.)

    path = "c:\\users\\jcb\\Desktop\\skins\\dds\\" + filename     <<< MODIFY THIS. THE SCRIPT WILL SPIT OUT THE DDS IN THIS FOLDER.

Save the file.
Restart GIMP.
Now, in the main menu, you should see Image -> Make DDS! (the very last item under Image menu)

 

How to use the plug-in:
Let's say you have modified the template and it's ready for export. First, go into channels and locate the channel you want to use for mask. Re-name this channel to "Matte" (and save the template). The script will look for alpha channel called "Matte". If it doesn't find it, it will crash. (The script was made with WW1 airplanes in mind first and foremost.)
Click Image -> Make DDS!
Input name for new DDS file and hit OK.
After export, hit Ctrl+Z a few times (four times), to get all layers back.

 

make_DDS.py:

#!/usr/bin/python
 
from gimpfu import *
 
def plugin_main(timg, tdrawable, filename):

    image = timg
    layer = pdb.gimp_image_flatten(image)
    channel = pdb.gimp_image_get_channel_by_name(image, "Matte")
    pdb.gimp_image_select_item(image,CHANNEL_OP_REPLACE,channel)
    mask = layer.create_mask(ADD_SELECTION_MASK)
    pdb.gimp_layer_add_mask(layer, mask)
    final = pdb.gimp_layer_new_from_visible(image, image, "Final")
    pdb.gimp_image_insert_layer(image, final, None, 0)
    layer_for_export = pdb.gimp_image_get_layer_by_name(image, "Final")
    path = "c:\\users\\jcb\\Desktop\\skins\\dds\\" + filename
   #                 (image, drawable, filename, raw_filename, compression_format, mipmaps, savetype, format, transparent_index, mipmap_filter, mipmap_wrap, gamma_correct, srgb, gamma, perceptual_metric, preserve_alpha_coverage, alpha_test_threshold)
    pdb.file_dds_save(image, layer_for_export, path, filename, 3, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0.50)
 
register(
        "make_DDS",
        "Flattens the image, adds mask (Alpha channel), exports as DDS",
        "Flattens the image, adds mask (Alpha channel), exports as DDS",
        "Jakob",
        "Jakob",
        "2020",
        "<Image>/Image/Make DDS!",
        "RGB*, GRAY*",
        [
            (PF_TEXT, "filename", "File name", "J2_test.dds")
        ],
        [],
        plugin_main)
 
main()

 

Hopefully it will save you some time and take away the boring routine.

 

S!

 

P.S.: The script is quite dirty, no conditions to make it foolproof. A "Hello world" in Python for me. But it works (at least for me). Feel free to modify it to suit your needs.

[Reinhardt]

I don't know what I'm doing wrong. I'm using the colour curve method but it gets rid of reflections altogether. I tried lessening how dark I make it but it makes no difference. If I don't make my own alpha layer, the skins are too shiny. If I do this, they are too matte. I can't find the "colour definition tool" either.I'm using GIMP 2.10.12. 

Edited April 20, 2020 by Reinhardt

[LizLemon]

Try saving the skin as .png or .tga and converting to dds with compressonator; https://github.com/GPUOpen-Tools/Compressonator

 

In general don't use gimp for saving to dds - it has awful compression handling.

[Reinhardt]

Is there a tutorial somewhere for the latest version of GIMP? (I'm using 2.10.12) I'm confused about which method for getting rid of the shine I should be using. After copying the alpha 1 channel to the layers dialogue it doesn't turn the image grey like it does here. (I'm guessing there's another step with my version of GIMP.) I gave up like 6 months ago, now I forget what methods I've already tried. 

[jollyjack]

Now how do you set the alpha channel in Photoshop CS6?

 

[RNAS10_Oliver]

3 hours ago, jollyjack said:

Now how do you set the alpha channel in Photoshop CS6?

 

 

I'm using CC but am sure that is probably the same. If that is one of the templates then an alpha channel already exists. From my knowledge there's no need to set the alpha channel etc as such. Just create one (and appears you have one) and when saving make sure that in the settings for your DDS that you are saving colour and alpha. Also you can have multiple alpha channels and in which case the top most alpha channel gets used from what I've found.

 

The settings to use for your DDS probably depend on the plugin that your using. I'm using the Intel Texture Works one and have to use these settings;

 

 

[jollyjack]

Probaly the wrong term, should have used 'edit the alpha channel' ..

 

I have the NVIDIA plugin, saving with interpolated alpha channel seems to be the DDS format for IL2.

However what i meant is get these nice light effects on a metal skin. f.i. Just ordered a book: Photoshop CS6 for dummies. Fits me, feel like one ...

Edited November 10, 2020 by jollyjack

[Na-zdorovie]

yep in cs6, you allready have the Alpha, just click channels tab, if you havent got that then window/channels, itl appear as a tab, drag that to your layers tab till highlighted, let go and itl be there next time

[Skywarp]

Hi,

 

I'm trying to achieve the shining effect in dark colors like this:

 

 

 

But the dark blue becomes light:

 

 

 

Any tips?

Edited September 28, 2021 by Skywarp

[jollyjack]

On 3/22/2015 at 1:47 PM, 6./ZG26_5tuka said:

http://fs2.directupload.net/images/150322/fncfm5hr.jpg

 

Hi Stuka, could you maybe repost the EXAMPLE pictures, i only get the above there. The GIMP images are OK. Thanks JJ

 

Made an RTF file for your post, maybe put them in here where needed and rezip -repost is easier?

alpha-channel-tutorial-for-gimp-advanced-skinners.zip

Edited July 5, 2022 by jollyjack

[JGr8_Leopard]

Hi, How to create a new alpha channel from an existing template?
I edit ready-made skin templates. They have an alpha channel that has weather effects and scratches built in. I want to turn off some of the weather filters and scratches from the template and then edit the alpha channel the same way. How can I rebuild the alpha channel according to my changes? Photoshop CC

Edited September 26, 2022 by JGr8_Leopard

[jollyjack]

A bit late: For Photoshop and probably Gimp too you could start with the Alpha PSD when provided.

If not deselect the layers you don't want and save what remains as greyscale PNG. Import that as Alpha (replacing the old one).