Hey Ron,
It sounds like you're building a pretty intricate system for procedural landscape design in Unreal Engine with Houdini, and that’s awesome! Let me try to address your questions one by one:
1. Chaining HDAs together
Yes, you can absolutely chain multiple HDAs in Unreal. The output of one HDA (such as a modified heightfield) can be passed as input to the next HDA, allowing for a sequence of operations. For this to work properly:
Make sure the type of input/output is compatible between the HDAs (for example, heightfield data should be passed from one heightfield operation to another).
In Houdini, the "heightfield" data type is particularly important when modifying terrain, as it encapsulates both the heightmap and associated layers (like masks).
2. Landscape distortion and stretching
The issue you’re describing with the landscape getting distorted and stretched likely stems from a mismatch in the terrain resolution or scaling between the different HDAs. When you’re working with landscapes in Unreal, make sure the resolution and scale of the terrain (in terms of the number of grid cells) are consistent across all the HDAs.
In the first HDA, ensure you are not altering the landscape’s resolution or transforming it in ways that lead to unexpected stretching. You should aim to preserve the aspect ratio of the landscape as you pass data between HDAs.
3. Projection of paths onto the terrain
To project curves (paths) correctly onto the terrain in Houdini, you need to use tools that can ensure the curves are placed in the 3D space relative to the heightfield. The curves should be deformed to follow the shape of the terrain:
Use a heightfield projection node to align curves or points to the surface of the heightfield.
Make sure the curves' input is normalized correctly based on the terrain's resolution and bounds, or they might not map correctly.
4. Layer data passing between HDAs
Yes, you can pass layers (such as masks or textures) between HDAs. Layers (including masks) can be treated as inputs/outputs in Houdini. When one HDA creates a mask, that mask can be used in subsequent HDAs for things like spawning assets or applying additional modifications.
You can expose those layers as inputs and outputs in the Houdini Asset parameters.
When exporting the heightfield from one HDA, ensure that any associated layers (like masks or erosion data) are also output.
5. Final Modular System Setup
For your modular landscape system in UE4:
Create each HDA as a separate, reusable tool (like an erosion tool, a path tool, an asset spawner, etc.), which takes in a heightfield and outputs a modified heightfield or a set of assets.
In Unreal, each of these HDAs can be added to the landscape workflow without breaking the pipeline, and the landscape can be adjusted dynamically in UE4.
For the
landscaping Tucson [
legacylandscaper.com] process, a similar modular system could be used where terrain is modified through erosion, paths, and other features, creating a more dynamic and flexible approach to designing desert landscapes or rugged terrains.
Final Tip
When testing your HDAs in Unreal, it’s good to start simple and then build complexity incrementally, ensuring that data flows correctly between HDAs and the landscape itself doesn't distort unexpectedly.