Random Detail material

how can achieve this using material editor od ue4?

Author a greyscale mask, that would contain all possible placements of objects with varying level of brightness from 0 to 1. Then select only certain range, depending on something pseudo-random, like world position of a tile. Layer down several of these for more randomness.

ok, so that is how i can randomize.
But how to locate several details like in the picture?
Someone mentioned on discord using texture bombing but the function uses DDY DDX and those doesn’t work on mobile Es2

This forum doesn’t have someone from epic’s staff as contributor?

So, I do something similar with the Perfect Tile System on the Marketplace:

1 - Make a black-and-white map with noise: all icons will appear on pixels colored in white. Yes, PIXELS colored in white. You don’t need this map to be very large, 128x128 is large enough to almost completely eliminate tiling onscreen.
2 - Import map as linear grayscale with Nearest Neighbor filtering. This keeps it nice and blocky when zooming close.
3 - In the shader, lerp between the background material and the icons. Tile the icons many, many times.
4 - Find the right scale settings so your black and white map perfectly matches the icons. If you have 128 pixels in your map and you have 32 icons in one UV space, you need to tile the “Tile map” by 1/4: TM scale = 1/(Tile Map size/# of Icons). 1/4 = 1/(128/32).
5 - Multiply the Tile Map by the icon’s opacity so everything is blacked out except the icons in the white space.

And voila! pseudo-random icon placement on your tiles! Of course you’re limited to working in square sections, but it works, and runs very fast!

Hi. We are going to try that!
thank you.
Btw my question is that in others forums they are moderated by epic staff except here.

I kind of made it work.
now i have to find a way of make it random per mesh

You can create parameters that move the “Tile Map” around. You can use the object position in world space or supply a random variable from the Blueprint to get a random result per-object. Using Floor or Ceil will clamp the value to the highest or lowest integer, then divide it so a value of 1 = 1 tile shift. If you’re making flowers, I suggest you don’t have too much objects visible: a 50:50 spread is too thick, it’s better to use this for accents.

Also, if you don’t make a black and white TM but instead use a grayscale noise map, you can use the random values in the grayscale map to do a lot of cool things: randomize the color of your flowers (hue shift), control the abundance of flowers (threshold, use the If node), and lots of other cool stuff! Since Epic doesn’t support 1-bit textures, you’re better off importing a random grayscale map and then controlling it through material nodes to fit your needs. You can get a lot of mileage out of this method.