How to Spawn Models with the Particle System in Blender

Mass placing objects such as trees on a terrain is easy with Blender's Particle System.

Spawning Objects with the Particle System

Start by adding the Particle System by opening the Particles tab and clicking the plus button. Change the Particle type to Hair and enable the Advanced setting.

Expand the Render section, change the Render As setting to Object and set the Instance Object to the object you want to use.

Fixing the Rotation of the Objects

To fix the rotation of the objects, rotate the original object on the X axis by -90 degrees. Now apply the rotation by pressing CTRL + A and choosing Rotation.

You can now hide the original object.

Setting a Random Size and Rotation

To set a random size for the spawned objects, change the values of the Scale and Scale Randomness settings.

To set a random rotation for the objects, enable the Rotation setting and expand it. Set the Orientation Axis to Global Z. Lastly, set the Phase to 1 and Randomize Phase to 2.