I found this great example: https://www.babylonjs-playground.com/#9MPPSY#5
It shows how to ‘paint’ on a BABYLON.Mesh.CreateGroundFromHeightMap.
I am having difficulties transforming this example to paint on a model, which is gonna be an imported 3D model. Perhaps a blender model.
Here’s my adaptation so far, using the default skull for now: https://www.babylonjs-playground.com/#UGRI6K#6
I’d like to paint on that skull just as I can paint on the ground area
Any tips/help is appreciated!
Interesting. And thank you for fiddling!
I’ve tinkered a bit with your code, trying to get an understanding of your sticker-approach.
Skull-import works, but I am unable to assign the decal…
https://playground.babylonjs.com/#UIVCZ3#9
Hi. There is no limits. Sky is the limit 
It is not working on skull for 2 reasons.
It has color attribute and it doesn’t have uv defined
If you set the color attribute to white and add some ‘fake’ uvs, you’ll see that the texture show up, but looks messy
https://playground.babylonjs.com/#1W8W1W#2
So I recomand you to try on other mesh, with UVs already defined, as example here
https://playground.babylonjs.com/#1W8W1W#3
https://www.babylonjs-playground.com/#UGRI6K#8
There are also decals
@MarianG and @Necips , thank you so far. After getting the basics right, I’ll try and add both sticker/decal option and the paint option from a selection-menu.
Now I have a single texture as well, after experimenting with different values of assetsManager.addImageTask
But I do not understand how to get rid of the ‘ground’… The painting on the ‘Dude’-model miraculously only works with "ground.actionManager.registerAction( … " enabled. Why does my code behave like this?
Please take a look at line 226 / 230 in https://www.babylonjs-playground.com/#UGRI6K#10
Thank you. Not sure why I can disable the ground in your #11 version - as opposed to the #10 version. But this works now!
So my next step is implementing an external model, including a decent UV map. Again, thanks for the reference, @MarianG … Perhaps a layered model, so I can paint on different parts/meshes (enable skin, skull, brain).
After that I’ll try and add the selection for decal || paint…
Thank you all!
hmmm… So I now have integrated Paint & Decal: https://www.babylonjs-playground.com/#UGRI6K#12
The painting-part works, thanks to @MarianG
But when I apply the material from the sphere (aka mesh) to the dude (aka skullTask), the decal won work on it: https://www.babylonjs-playground.com/#UGRI6K#13
See lines 81, 82 & 333, 334 … What am I doing wrong / do I need to understand?
Also embedding the actionManager into the skullTask.onSuccess is not working. See https://playground.babylonjs.com/#UIVCZ3#10 ( building forward onto the suggestion of @Necips )
I am looking to understand why.
Here is with decals. chek 335 line.
https://www.babylonjs-playground.com/#UGRI6K#14
Actually I didn’t understand what u wanted do in the last pg, so I cleaned it up a little bit, I hope I didn’t remove something what you wantd 
https://playground.babylonjs.com/#UIVCZ3#11
@MarianG You have saved me so much time and helped me so much to better understand babylonjs.
THANK YOU!