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Houdini and Unreal use two different coordinate systems.
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Houdini uses a Y-up right handed coordinate systems (unit: meter)
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Unreal uses a Z-up left handed coordinate systems (unit: centimeter)
Axis conversion ¶
Houdini Engine for Unreal plugins converts all the transforms and geometries (positons, normals, etc.) from Houdini to Unreal’s coordinate system.
For example, an asset located at (0, 10, 5) in Houdini will be located at (0, 500, 1000) in Unreal. Despite the different values, both the unreal asset and Houdini assets will be at the same location.
Vector3 Parameters ¶
Vector3 parameters such as Integer or Float are identified and displayed using Unreal’s XYZ coordinates. However, other parameters do not.
This means a Y-position parameter in Houdini controls the Z-position in Unreal’s coordinates system.
To prevent Vector3 parameter from switching its Y and Z in Unreal, you need to set the parameter tags.
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Set the Tag Name to
hengine_noswapand the Tag Value to1.
See Parameter tags for more information.
This results in Houdini and Unreal having the same XYZ and orientation values but different visual location and orientation.
