Using PCG to populate cliffs and rocks on landscape slopes

[Sypher-66 (Sypher)]

I’m trying to create a PCG graph that, as the title suggests, populates cliffs and rocks on landscape slopes.

The issue is the cliff meshes are orientated in a particular direction that i need to maintain and i can’t find any transform options that make this happen.

Basically i need all the cliff meshes to maintain Z axis pointing upwards, ideally rotated with the surface normal so they fit flush to the slope. The Y axis should point forwards using the surface normal and the X axis should be unchanged. I think that is correct.

using absolute rotation seems to use world position and ignore the surface normals but at least the mesh is orientated in the correct way

without absolute rotation, its using the surface normals which is good but i can’t find a way to get the Z Axis uniformly pointing upwards

Anyone know how i can achieve such a thing? This seems quite possible in houdini but can’t find an easy way in unreal. thanks in advance

[oliwerlundberg]

Did you find a solution? having the same problem

[BRGEzeHulton]

Hi @Sypher-66 I have an idea that could be helpful for you. Use a Custom Node inside your PCG graph to manually adjust the rotation of each point based on the surface normal.

• Add a Custom Blueprint Node to your PCG graph.
• Inside the PointLoopBody, apply this logic:
• Normal = GetSurfaceNormal(Point.Position)
• Rotation = MakeRotFromZ(Normal)
• Point.Rotation = Rotation

Tutorial:

Unreal Engine 5.2 PCG Tutorial - Rotate Objects to Face a Point

500×500 2.84 KB

I’m trying to place rocks on the steep parts of the landscape. Which works fine. But most rock assets have a direction, so I need to place them facing upwards. My points are aligned with the landscape, but I need them to also point “up” the slope. Any idea where to start? [image]

This video might also be helpful

Unreal Engine 5.2 PCG Tutorial - Using a Height Filter to Place Trees on a Mountain

Please reply in this thread if it was helpful or if you have any questions. I hope you can resolve it.