This floating island terrain was created in Houdini, combining heightfield-based topography with noise-based geometry for the underside.
Top Surface: Heightfield-Based Terrain
- Initial Blockout and Masking: Used Heightfield Paint to sketch the basic layout based on the blockout, defining raised hills and recessed water areas; Generated an irregular island shape by jittering points on a circle using Point Jitter and resampling them, creating a mask for the heightfield.
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Edge Transition Mask: Expanded and shrank the mask,
then subtracted the shrunk mask from the expanded one to obtain an edge region;
Applied a blur to smooth the transition and used Heightfield Wrangle to gently slope the edge downward, ensuring a natural connection with the island’s underside.
- Surface Detailing: Added natural variations to the terrain with Heightfield Noise and Distort; Converted the heightfield to polygons and used a Boolean node to trim the geometry according to the island's shape mask.
- Base Setup: Reversed the top surface geometry to serve as the foundation for the underside; Created an attenuation mask by calculating the horizontal distance from the island center using an Attribute Wrangle, storing it in Cd.x (with the outer edge set to 0).
- Noise Application: Applied procedural noise using Point VOP to modify point positions based on their distance from the center; Multiplied the noise by Cd.x to ensure the deformation fades out towards the edges; Adjusted the vertical position of points (y) using an Attribute Wrangle to achieve a natural, tapering effect for the underside.
Integration Trick for Unreal Engine
- Directly importing the heightfield into Unreal Engine can result in issues:
- Using Opacity for Masking: Leads to jagged edges around the island due to precision limits.
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Importing as Geometry: Prevents using Unreal's Landscape tools, making it difficult to modify terrain colors or details later.
- Solution: Imported both the geometry and heightfield into UE; Used Runtime Virtual Texture (RVT) to store the painting results of the heightfield landscape; Configured the geometry material to read from the RVT, enabling real-time terrain color painting while maintaining sharp and clean island edges.