14: Object Placement with Weight Painting
To gain more control over where certain objects appeared, I used weight painting to influence the density of instances, specifically for placing bushes.
Process
I added bushes using the familiar Instance on Points node setup, with Random Value nodes controlling their rotation and scale. Instead of relying solely on randomness for placement, I switched to Weight Paint mode on the main ground mesh.
In Weight Paint mode, I painted the areas where I wanted the bushes to appear. The painted weights correspond to numerical values that can influence various aspects in geometry nodes.
Back in the node editor, I used the Distribute Points on Faces node and connected the weight attribute to its Density Factor input. This meant the density of the bushes was directly influenced by the weight painting.
This method allowed me to maintain randomness in positioning and size while precisely controlling where bushes would appear.
Nodes Used and Their Functions
- Weight Painting: Paints weight values to control density.
- Distribute Points on Faces: Uses weights for point distribution.
- Attribute: Accesses weight paint values.
- Random Value: Adds variation in rotation and scale.
- Instance on Points: Places bushes based on weight painting.