The Challenge
Sometimes, we just want to quickly establish a falloff attribute, and we don’t have handy toolsets like MOPS installed. So, here’s a quick wrangle to lay out a falloff attribute from the left-right bounds or top-bottom bounds of a geometry, depending on the axis you chose.
The VEX Code
To map geometry bounds to a 0–1 range in Houdini, use a Wrangle node with the getbbox() function. This calculates the minimum and maximum bounding box corners, then uses fit() to normalize a custom attribute (e.g., position) to a 0-1 range based on those bounds.
// 1. Get bounding box of input 0
vector min, max;
getbbox(0, min, max);
// 2. Map position to 0-1 based on bounds
f@falloff_x = fit(@P.x, min, max, 0.0, 1.0);
How to Use
Great to establish falloff attributes across the dimension of a geometry. Feel free to append an Attribute Remap node to remap this new attribute (it’s “falloff_x”, in this example) into meaningful attributes for your setups or simulations. Enjoy!
