Guides A guide for Sim textures

@Case asked if I knew something about sim textures in clothing and if I could make a guide to go together with my guide for Alpha textures.
Well, I don't know much, but something is more than nothing, and maybe it could be useful to others, so I'm having a go at it.

Help me improve this guide
What I'm about to say may be wrong, too simplistic, misleading, and for sure can be improved. If you could help me improve this guide by leaving notes in the Discussion area that would be most appreciated.

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What is a Sim texture?
A Sim texture is a image file that tells VaM how stretchy a clothes item can be. ⚠ this is how I picture it, could be very wrong ⚠

This information is provided by the red channel in the image. A spot with a red value of 255 (full red) will have no stretching, while a red value of 0 will have maximum stretching.

If you've opened the VARs of some clothes, you may have seen some textures painted red and blue (or black). Those were the sim textures for the clothing item.
As mentioned, only the red channel matters for Sim, the green and blue channels are ignored. As a background for the red areas you want to add, it's common to use blue (255) instead of black because it's more visible, but the result is the same sim-wise. Do you get the title background above now?

Sim clothes in action
In this guide I'm using SupaRioAmateur's FitnessStar Workout Tanktop and FitnessStar Leggings for demonstration purposes. I hope that's ok, thank you SupaRioAmateur.

This video shows the FitnessStar Workout Tanktop with the provided sim texture:
(the difference between "Sim enabled" and "Undress" will be address later)




And these images below are two textures present in the VAR for the Workout Top shown above:


If you focus on the video during the "Sim enabled" part before the "Undress" was checked, you can notice that the shoulder straps do not flow as much as the rest of the top. When you overlay the diffuse and sim textures above you can see that the shoulder straps area has a lot more red (sim texture) than the rest of the top. So, remembering how sim textures work: more red = less stretchy, which fits well with what the video shows.

Ok, so that's the background, now off to the guide on how to make these textures.

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How to make Sim textures
I'm using information from other clothing related guides in the Hub and I'll show links to those at the end of this guide. A thank you to those creators that enabled this guide to exist.

There's several scenarios and options regarding clothing items:

You have clothes from Daz, Blender, and others
You can do all kinds of things and even use those tools to paint and export a sim texture overlayed over the clothes in a 3D environment. This is something shown in SupaRioAmateur's guide - Cloth Sim Paint With Blender - but that's not the focus of this guide, here I'll focus only in the options below.

You have clothing in VaM and access to the textures used (diffuse especially)
The diffuse texture is a 2D representation of the clothing item, and you can use this as a guide to paint your sim texture. Depending on the clothes, you may have more than one per material and each can have its own sim texture too.

You have clothing in VaM but no access to the textures used
No problem, you can use VaM to make a UV map of the clothes and use that like you would the diffuse texture. Needs a bit more guessing but is fine. To learn how to make one check my Alphas guide. Depending on the clothes, you may have more than one material used and each can have its own sim texture too.


Tip:
If you have a clothes item that already has simulation you don't have to go to the Clothing Creator to do all the below process steps. You can skip to the Sim texture making process and change it in the Sim texture field value (item B10 below).


Clothing Creator
Ok, you have your clothes in VaM, it's time to load them in Clothing Creator:



The Clothing Creator is also what you'll use when you bring clothes from Daz for example. There's all kinds of options in this place, and I separated them with A and B.



Examples for different red values using a uniform sim texture:


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Beyond uniform Sim textures - custom Sim textures

This is the part where the diffuse textures or the UV maps come in. They will be used as a guide to see where you can customise the red value to make your clothing be more realistic. You can use any 2D image editor you want that can handle layers and a paintbrush. I use paint.net, it's free and good for simple jobs. One that handles layers is very useful because you can overlap the diffuse or UV map with the new Sim texture you're making, but do whatever works for you.

The diffuse images are usually 4K in size, but unless you're making a high precision Sim texture you don't need all that. I usually resize the diffuse/UV to 1024px.
After resizing, I duplicate the diffuse layer and paint it all blue - RGB(0, 0, 255), this is going to be the Sim texture.
I leave the diffuse as a top layer and set a opacity to half. Now on the Sim layer I paint in red (values based on your needs) the areas I want based on the faded diffuse layer.

The way you do the above is entirely up to you, whatever works. Check on my Alphas guide the section "Saving and testing the results in VaM" for a live testing of your Sim texture.

Tips from SupaRioAmateur's guide:

• In general, you would like to keep thing above shoulders stable(253/0.99), chest area in the mid(128), lower part complete free flow(0)
• Don't use Red channel 255, it will lock cloth to body and can't undress. Use 253/0.99 instead.

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Undress and nearby joints

This part I know very little.
Undress seems to be on how sticky the clothes are?
The nearby joints (8) appears to be regarding the clothes mesh, whether they're connected or not, and it could create joints to keep the clothes together until a threshold is passed.
Could really do with some help on this part.

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More guides you should check out:


Probably more related guides around, I hope more will come too.