Can you please re-describe the problem? It’s difficult to understand the second sentence. Posting a pic might help too.
Hello,
I have a towel two sided with a image on te surface. By Cloth Sim overlap each side the other and so the surface results looks.
Is there a way to avoid this or do i need for Cloth Sim always only one side? (Do i need to cut off one of both?)
Greets
I am asking, if there is a way if i have cloth with two sides (front, back), that these two sides are not overlaping? 
Is Self Collision enabled? If not, try that. There’s also the Cloth Content Examples map to use as a reference for various Cloth settings and such.
If I understood correctly you want to simulate cloth on a model that has thickness?
You can do that with PhysicsMesh. It’s basically just another model (usually a plane) inside, that is roughly of the same shape as your original mesh (or GraphicsMesh). You need to create your cloth simulation on that plane but apply cloth to your original mesh. This way your GraphicsMesh will follow the simulation on your PhysicsMesh. You can then disable material on the PhysicsMesh, to get it out of the view.
hope this helps~
Do you mean the first 3 options? And no do not work. Where can i find the Cloth Examples, do you have a link for me?
I’m unfamiliar with the Clothing Tool, and APEX cloth. And the Cloth Examples map is in one of the main folders of the engine, either Content or Engine Content. Do a search for “cloth” in the content browser search bar when in one of those folders and should be able to find it.
Here’s a link to the doc page, specifically a reference of the Config properties:
It’s quite a bit of properties to adjust for creating exact effects. I suggest searching for a tutorial that illustrates how at least a few of those properties affect a two-sided cloth, specifically a cloth type that is similar to or the same as a towel. YouTube has a ton of tutorial videos for UE4, so starting there might be the best option.
Sry for the late replay.
I solve this problem by turn off two sided in the Material Master. So the backside of the overlaping thickness mesh will not be visibile anymore
Interesting. Two-sided in the cloth’s material or in the cloth’s mesh details? There’s two-sided shadowing, two-sided lighting in Lightmass settings for a mesh, and two-sided for materials, lol. What one was unset?
Cloth Material. I have a Material Master that is two sided. So i switch my Material instance parent to one without and so it works 
But i had no idea that two sided shadowing / lighting also exist. I learn something new again, thanks haha