Get Landscape height in material applied to a static mesh

[Chosker]

@Maximum-Dev

I’m pretty sure the workflow is a bit different from trees to rock piles though as for trees you only want the base verts to be affected but for rock piles all verts should be affected otherwise the mesh gets stretched a lot. For tree as you guys suggested, masking might work. But for rock piles masking doesn’t work and without masking entire mesh gets flattened to terrain surface.

the workflow is different from anything that needs a different kind of masking of course.
nothing has to be flattened to terrain surface though. you can offset the entire mesh using the center as the point of comparison (instead of per polygon), which would literally just “move down” the mesh. as long as it’s small things without collision (i.e. individual stones) you should be fine. then again if the object is a small thing with its own center I don’t see why it wouldn’t be correctly snapped in the first place, so…
if the object in question is a cluster of meshes then using the pivot painter workflow would provide a good solution to be able to offset each piece of the cluster-mesh from its individual center

@mgKelley

It turns out this question has been asked in the forums.
Using 16bit heightmap in material to recreate landscape

The Epic ‘Kite Demo’ has Terrain Heightmap sampling from a Material applied to static mesh on the rivers and lakes in the sub level maps.

For best results the height map needs to be 16 bit .png (can use 8 bit but that may cause stair stepping ).
Load the .png Heightmap as HDR (RGB, no sRGB) compression. In the material your Heightmap sample type should be ‘Linear Color’ and sample from the Red channel.

interesting, good info!

@mgKelley

Here is results I got on the kite demo asset ‘SM_Scree002b’ rocks. I exported the FBX and painted the the vertices that the terrain blending would effect. You can just paint the vertices per-instance in the Unreal Engine Editor.

you can propagate the painted information from the instance to the mesh asset, no need to export anything
one of the buttons of the mesh paint tool does exactly that. make sure you don’t use “small icons” in the editor because if so, that button is invisible (small icons setup is full of bugs)

@mgKelley

I also set the material blend mode to ‘Masked’ and checked ‘Dither Opacity Mask’ and used the painted vertices to set the ‘OpacityMask’ material attribute. The result is a decent blending to the terrain that looks good from both a standing and crouched position of the player. A player in prone position would see some blending artifacts but its good enough for in game imo.

Here is the material nodes, I got the UV calculation and Heightmap lookup from the ‘KiteDemo’.

Your ‘HeightmapScaleZ’ and ‘TerrainOffset’ will differ, I found mine through trial and error. Subtracting ‘Absolute World Position’ locks the height to your terrain, so what ever your vertices world Z is, this node graph will give you an offset to your terrain. The ‘MakeFloat3’ vector plugs into your materials ‘WorldPositionOffset’ attribute. The ‘KiteDemo’ has this graph as a material function, great idea, I am going to do the same so it can be easily applied in any material.

If you don’t have your height map or have modified one with sculpting, the Unreal Editor can export it for you in 16bit ‘,png’ format.

interesting results
still not a fan of using the Dither technique for such things myself. you get all sorts of small artifacts depending on many factors but mostly it bothers me that the more a game relies on TemporalAA, the more you end up building an “ulgy mode” for when the player disables TemporalAA