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s3nova
26th Dec 2015, 3:24 AM
Hello, I'd like to present this specular image editing tutorial with the main focus on making clothing shiny. The subject is not new and maybe the method neither, but I just wanted to present a comprehensive and easy to follow tutorial. So everyone from newbie to veteran can use it. Please let me know if it was useful and what your experiences are with the different values you experimented with!

Why you should try it: you can now add real live shine to even the dullest EA material without having to edit the original texture to simulate shine.

Kind regards, S3nova.

German version here / Deutsche version hier (http://modthesims.info/showthread.php?t=569425)

Tip: first read the tutorial completely, some things are explained in more detail in relevant sections. It's quite some text but don't feel discouraged, just take some time to read first. Then set up things in GIMP and then follow the tutorial again while working on your project. After the first few trials you'll find that everything for 1 object can be done within 5 minutes. Success!!


Overall workflow
1. Preparation
2. Select and clone source object
3. Export specular image
4. Edit specular image
5. Import edited specular image
6. Test in game

Read the rest of this tutorial for explanation and understanding. Once you understand, you can do with a simple walkthrough in 15 steps, given here (Abbreviations explainder under 1.3):
1. from reference data in this tutorial (at end) select RGBA-values that seem suitable for your project and write them down
2. S4S: select object, clone it as CAS Stand Alone and save under meaningful name (when experimenting add RGBA values to filename)
3. S4S: export texture as Org_TEX.png, the RLES-Entry under Warehouse (= the specular) as Org_SPEC.png (you'll automatically receive Org_SPEC.mask.png from S4S)
4. optional: GIMP open Org_TEX.png and add RGBA info to texture (by spaypainting or adding text, just to make it visible ingame, do this when experimenting)
5. GIMP: open Org_SPEC.png
6. GIMP: menu Colors / Components / Decompose and select Options to decompose to 4 separate images (1 grayscale image per original color channel)
7. GIMP: Tab Colors: select the value you selected in step 1. for Red, set all colorsliders to same value so you always get a shade of grey
8. GIMP: select image corresponding to Red-channel (ends with -red.png)
9. GIMP: bucket fill relevant areas
10. Repeat steps 7. to 9. for the images corresponding to green, blue and alpha channels
11. GIMP: menu Colors / Components / Compose, select the right image for each color in Compose Dialog (don't swap things here!) and click Compose
12. GIMP: check new image by moving mousecursor over edited areas and reading colorvalues in Tab Pointerinformation, correct if necessary
13. GIMP: export new image with meaningful name (add RGBA-values to name when experimenting)
14. S4S: Tab Studio import edited texture (optional), Tab Warehouse import edited RLES / specular image and Save
15. File Explorer: copy new .package file to /Mods folder and test in CAS and ingame



1. PREPARATION
Tools used: GIMP 2.8.16 Image Manipulation Program (https://www.gimp.org/) and Sims 4 Studio 2.6.0.8 (Sugar) (http://sims4studio.com/) Many thanks to corresponding authors!
No .dds plugins are required.

1.1 Setup GIMP
The use of GIMP can be confusing, because of its somewhat complicated interface. This is why you have to setup a few things in GIMP before you start.
A. Add the Tab ‘Pointer information’ to a menu in GIMP (Any tool window / Add Tab / Pointer)
B. Set the options for both Pixels and Units at ‘Pixel’: see attachment Pointer Info (http://thumbs.modthesims.info/getimage.php?file=1590370)
C. Furthermore the Tabs Colors and Layers should be visible, with the subtab ‘Scales’ activated, so you have sliders for selecting colors visible: see attachment Color Sliders (http://thumbs.modthesims.info/getimage.php?file=1590371)
D. Make sure you have the Toolkit visible (otherwise: Menu / Windows / Toolbox) and also the Tool Options Tab in any window (otherwise: in a window pick Tabs / Add Tab / Tool Options)

This setup will show you the RGBA (Red, Green, Blue, Alpha) values under the mousecursor at all times, which makes a great option to continuously check things. The histogram has no ‘live update’ feature and is not so useful here.

1.2 GIMP workflow
Off course there are multiple methods to edit channels and layers in GIMP. But in the case of editing a specular map, things have a different meaning:
Red value represents reflection sharpness
Green value represents reflection brightness
Blue value represents size of highlights in reflections
Alpha value represents overall amount of reflection

Although this can easily be written down, really feeling and understanding its meaning requires some experimentation. Some differences can be seen here: Overview channels (http://thumbs.modthesims.info/getimage.php?file=1590375) I hope they are useful in selecting the right values for your upcoming projects!

Problem in working within in a single image is that the Alpha-layer is always present and if you turn off its visibility you don’t see anything at all. This makes working with layers in a single image counter-intuitive and not easy. In my experience it is better to decompose an image into 4 greyscale images representing the RGBA channels, edit these separate images and then recompose the image. This can easily be done in GIMP, it is always clear AND visible what you are doing, things can be checked at all time etc. That’s why this is the method of choice here in my opinion.

By working with decomposed images, you will notice that they are named something like <original_filename>-red.png. If you edit such an image, you won’t see any red at all however. That is because this image represents only a single color channel and the pixels in it can only take a value between 0 and 255 (so it is effectively a grayscale image). This makes things easier for you, there is only 1 value to keep an eye on. In the resulting image, the image you are editing (let’s say red) will be that images’ red color channel (and so on for G, B, A).

1.3 Abbreviations and conventions
A little bit of experimenting can quickly cause a lot of files. To avoid getting lost I suggest you use the following naming abbreviations and conventions:
A = Alpha channel, R = Red channel, Green = Green channel, B = Blue channel (together as RGBA)
ORG_ = original image as resulted form export out of Sims 4 Studio, _TEX = a texture image, _SPEC = a specular image. Example: ORG_SPEC.png is the specular you exported from Sims 4 Studio (S4S).

While working with specular maps it is useful to use the following naming convention:
Rvalue_Gvalue_Bvalue_Avalue_SPEC.png in which each value is in 0 to 255.
Example: R85_G170_B_0_A170_SPEC.png is a specular you created with the mentioned RGBA values.

Separate colorvalues range from 0 to 255. Sometimes (in other tutorials) these values are expressed as a percentage, for example 64 = 25%, 128 = 50% and 192 = 75% and so on.

2. SELECT AND CLONE SOURCE OBJECT (Sims 4 Studio)
You should have an idea of what you want to make. In this tutorial we will try to change an existing clothing top in a top with a shiny satin look, so the emphasis will be on how to make this blouse shiny. The GIMP-part of the presented technique can be used for any object however. The main focus here will be on clothing. For this tutorial we will make use of the blue color variant of this blouse: see attachment Original (http://thumbs.modthesims.info/getimage.php?file=1590372)

With Sims 4 Studio this top can be cloned this way:
- via the button CAS, option Create CAS Standalone.
- select the blouse in blue (Filter settings: Gender=female, Age=Adult, Part Type=Clothing Top).
- click the Next button to save the package and use a meaningful name (when experimenting the aforementioned RGBA naming convention can be used).
If you wish, you can export the texture and add information to it in GIMP, like I did for the pictures used in this tutorial (‘Test’ or description of color values).

From this Overview of Channels (http://thumbs.modthesims.info/getimage.php?file=1590375) , choose which type of shine you like the best and write down the associated RGBA-values because we will use them later. The values used are focussed on the 85 (=33%) and 170 (= 66%) values, as they split the scale in 3 equal parts. This helps you to estimate the desired effect. Want more than 85 and less than 170 then choose value between them, less than 85 choose value between 0 and 85 and so on. In the grayscale images representing the RGBA channels 0 means black and 255 means white. (RGBA values are painted on texture. If no value is mentioned it is always 170 for Alpha and the original value for other channels).

3. EXPORT SPECULAR IMAGE
In S4S:
- select the Warehouse tab and find the RLES image
- click the Export button to export it and name it Original_SPEC.png
- leave S4S open for later use

You’ll mention that S4S shows two images, the left image will be exported. The right image is the mask and will automatically export with the name Orignal_SPEC.mask.png.

Remark: S4S will look for the .mask.png file when you import an edited RLES image. Sometimes useful, sometimes a problem. For some reason S4S tends to color the black parts of the mask with white when you import a new specular image. When this happens, not only the clothing but also face and arms etc. will become shiny.
If you want to make a piece of clothing shiny on all parts, then you better leave the .mask.png file.
If you want to make a piece of clothing shiny only on some parts, you will need the .mask.png file, because it determines which parts of the clothing will show shine and wich parts will not.
(if you run into trouble then reclone to get an object with the original mask file. Then you can try to edit the alpha of the specular image to create partial shininess / leave areas out that should not be shiny) Tip: you can often make use of the exported .mask.png file to copy a mask from. Apply this mask to every image (RGBA) you edit, this way you can keep shine out of unwanted areas.
When editing by hand the texture templates found here (http://www.sims4studio.com/thread/243/sim-body-texture-templates?page=1) and here (http://sims4studio.com/thread/62/fix-uv-map-template) can be very useful (thanks to and Orangemittens and Brujah).

4. EDIT SPECULAR IMAGE
This is the main focus of this tutorial. We will export the associated specular image, edit it and then re-import it. We will use R=85, G=64, B=0 and A=128 to create a nice shiny satin look: see attachment Result (http://thumbs.modthesims.info/getimage.php?file=1590373)

Open up GIMP with the prepared settings (see 1.1) and open the exported specular file (named ORG_SPEC.png if you followed this tutorial closely).

4.1 Decompose to 4 images
In GIMP:
- use menu Colors / Components / Decompose
- in the resulting Decompose dialog choose the following: Color model: RGBA, UNcheck ‘Decompose to layers’ and leave ‘Foreground as registration color’ unchecked
- then click OK.
- if the result is 1 other image, you forgot to uncheck ‘Decompose to layers’, close the new image and restart this section (4.1).
- you will get 4 images, corresponding to Red, Green, Blue and Alpha channels.

Since they are apart now, you can edit each channel as a separate grayscale image (as explained in 1.2). Clear and simple, because now you can see what you are doing and check your results by just moving the cursor over painted areas and see the values in the Pointer Information Tab.

4.2 Edit the separate images
Start with the image representing the red channel:
- set the RGB color sliders to 85, resulting in medium gray (or set to desired value as chosen for red)
- select the image with a name ending in -red.png
- select the Bucket Fill tool, under Tool Options select the value 15 for Treshold
- click the non-black areas with the Bucket Fill tool to fill them

Next image representing the green channel:
- set the RGB color sliders to 64 (or set to desired value as chosen for green)
- select the image with a name ending in -green.png
- select the Bucket Fill tool and fill the non-black areas

Next image representing the blue channel:
- set the RGB color sliders to 0 (or set to desired value as chosen for blue)
- select the image with a name ending in -blue.png
- select the Bucket Fill tool and fill the non-black areas (if present)

Next image representing the alpha channel:
- set the RGB color sliders to 128 (or set to desired value as chosen for alpha)
- select the image with a name ending in -alpha.png
- select the Bucket Fill tool and fill the non-black areas

Exception: You may encounter an image representing a color channel that has no black background but for example a lightgrey background. If you follow the current example of the blue top, this will happen with the green channel which has a gray value of 162 in its background. In general it is no problem to change this background to black.

4.3 Compose the result from the 4 images
Now you have a group of 4 edited images which should be composed into a new resulting image.
In GIMP:
- click Menu Colors / Components / Compose (NOT REcompose)
- in Compose dialog choose as Color model RGBA and use the dropdown lists to assign the right images to the right
channels. Caution: Make sure this is done correctly, don’t swap any channels here! See attachment Compose Dialog (http://thumbs.modthesims.info/getimage.php?file=1590374)
- the resulting image will have a name like ‘rgba-compose.png’
- move your mousecursor over the image and check the color values in the Pointer Information Tab
- check if the areas you edited have the right values, just to make sure you haven’t forgotten anything or swapped channels in composing the image.
- correct any errors and then proceed to 4.4

4.4 Export the result
When done, export your image to .png (default keyboard shortcut Shift+Ctrl+E), uncheck all boxes in the Export Image dialog and click the Export button. You can additionally save the image as GIMP’s own .xcf format. Use the RGBA_SPEC.png naming format (especially when experimenting, see 1.3).

5. IMPORT EDITED SPECULAR IMAGE

5.1 Sims 4 Studio
When experimenting you can use a texture with text painted on it or something like that.
- on the tab Studio import the relevant texture

In general you don’t need this step and you can proceed with:
- select tab Warehouse
- select RLES Image entry (probably still selected from last action in S4S)
- click Import
- importing a .mask.png file is not necessary (see Remark under 3.)

If you have prepared a maskfile for partial shine, then give it the same filename as the specular image, delete the .png extension in the filename and replace it with .mask.png. Importing it:
- S4S will import it automatically along with the specular image without any user feedback
- check its appearance in S4S, if anything outside the relevant parts is not black, then you’ll run into problems (whole Sim turns shiny)
- if this happens then see 3 for dealing with the mask file

6. TEST IN GAME
Copy the cloned object to Documents/Electronic Arts/The Sims 4/Mods folder, start the game, allow for custom content and find your edited piece of clothing. Any markings painted on the texture will be helpful to find your new creation back. Shiny things show their shininess best when moving, so make sure to always check your result in game (Create-A-Sim).

The result is shown here. (http://thumbs.modthesims.info/getimage.php?file=1590373) You are encouraged to experiment with different values! See attachment Overview Channels (http://thumbs.modthesims.info/getimage.php?file=1590375) (RGBA values are painted on texture. If no value is mentioned it is always 170 for Alpha and the original value for other channels).


7. SOURCES AND CREDITS

Format of references:

Title
Author
Link
Subject
Tools used

T: Basic guide to RLES-Specular Map editing
A: Untraditionalnerd
L: http://sims4studio.com/thread/1722/tutorial-basic-guide-specular-editing
S: Creating partial shine
T: Sims 4 studio, Photoshop, .dds file plugins


T: Creating Specular Images for The Sim s4
A: Sim_man123 @TSR
L: https://www.dropbox.com/s/jmif1gnjbnhr0mq/Creating%20Specular%20Images%20for%20The%20Sims%204.pdf?dl=0
S: Creating partial shine
T: The Sims Workshop, Photoshop, .dds file plugins

T: Advanced Specular Mapping Techniques & Step by Step Guide
A: Samanthagump
L: http://sims4studio.com/thread/1850/advanced-specular-mapping-techniques-guide
S: Creating partial shine
T: Sims 4 Studio, Corel PaintShop Pro X6

T: How to Create an RGB Specular for Objects
A: Kitkat
L: http://sims4studio.com/thread/1617/create-rgb-specular-objects
S: Creating object with differentiated shine
T: Photoshop, .dds file plugins, Blender for texture bake

T: A lot more joy!
A: moderator @sims4studioofficial.tumblr.com (?)
L: http://sims4studioofficial.tumblr.com/post/120668261961/a-lot-more-joy
S: Sims 4 Studio can now use .png files to edit the RLES specular, making the use of .dds plugins obsolete
T: Sims 4 Studio

T: Specular Map Edit need help
A: UntraditionalNerd
L: http://forums.thesimsresource.com/index.php?/topic/277345-specular-map-edit-need-help/
S: Dealing with problems related to shine appearing in wrong spots on Sim
T: None

T: Get to know the Emission Map
A: Untraditionalnerd
L: http://sims4studio.com/thread/2544/get-emission-map?page=1
S: Not used for current tutorial. Shows another way of using the RGBA channels to create an emission map, which makes clothing / objects emit light.
T: Sims 4 Studio, 2D editor with .dds file plugins


My experiences thus far:

[edit 27 december 2015] best results (http://thumbs.modthesims.info/getimage.php?file=1590621) for satin in decreasing brightness are (thus far):

R128_G96_B0_A170
R96_G96_B0_A170
R96_G64_B0_A170

- optimum of R in 64 to 128 and G also in 64 to 128, higher values give liquid-like reflection
- blue plays no role for satin-look, so keep B=0
- increasing alpha means increasing overall amount of light reflected, but this drops above A=224, so A should not be chosen above 224

Reference pics: Red lower than green (http://thumbs.modthesims.info/getimage.php?file=1591060), Variations of red and green (http://thumbs.modthesims.info/getimage.php?file=1591062), Effects of alpha (64 to 255 @ R128_G128_B0) (http://thumbs.modthesims.info/getimage.php?file=1591064) and Optimal values for satin (http://thumbs.modthesims.info/getimage.php?file=1591063).

Attention: lighting in CAS is quite strong, so reflection to. Ingame things are most often somewhat tempered, although this depends on the direction of the sun outdoors. For example of differences see here. (http://thumbs.modthesims.info/getimage.php?file=1591065)

- using alpha alone (and leave RGB in original state) is often already quite useful on its own (creates something like silk or satin look)
- alpha has influence on RGB, but RGB has no influence on alpha
- red in high value shows a reflection of a window, this is a general cube map used for reflections (in TS4 it is not the surroundings that are reflected)
- green above 128 tends to create a very reflective vinyl-like look in combination with green (creates something like latex or vinyl look)
- blue is somewhat difficult to interpret, as it seems just to soften the reflection of the cube map but seems to have only small influence on overall shininess

Any additional information and experiences are welcome! Happy modding!

plasticbox
26th Dec 2015, 10:18 AM
Looks like a very comprehensive tutorial, thank you =). Say can you edit your post title to include "Gimp"? That would make it easier to find for Gimp users, I think. Thanks!

s3nova
26th Dec 2015, 3:10 PM
Thanks for your comment and see title . . . you're welcome!