Hello, im new to unreal and just learned about RVT and was trying to blend megascans assets with my landscape material. i have it working but the RVT seems to stretch when blending with any vertical part of a mesh. It looks great on flatter surfaces but has this stretching on more vertical surfaces, i added two pictures one that shows the stretching and one that shows it looking fine on a flatter mesh area. Any idea why this is happening?
RVT is only a top down capture of the terrain. Imagine, in a sense, a camera from up above capturing an orthographic image of the terrain. You then map that image data, plus the data of the height which is also captured from the volume, in world space back to whatever object is in the world. You do this by projecting again in a top down perspective. Which will result in really nice looking results when the surface is perpendicular to the projection direction, and will be stretched (because it is receiving much less pixel density due to the projection angle) when it is parallel to the projection angle.
You can do a couple of things to help mitigate this. Like using a calculation with the world normal to have it blend more fully when the surface is more perpendicular to the projection angle for example. Then blend less when it isn’t perpendicular. This would help it blend less when it shouldn’t be blending as much and help with that stretching issue.
An easier fix would be to shorten the height of the blending or add in an additional triplanar noise mask to help mask the blending issues you are seeing. That is what I have done. I just mask the world height twice. Once with the actual RVT height, and again with a triplaner noise mask but with different values to give it a dirt like noise offset that dissipates the stretched look but retains the texture. Then I also blend the normal of the terrain with the mesh in the blending along with the color so the transition is really smooth.