Make it Rain

Create the Rain Creator: particle emitter

• Undock the toolbox panel. Click on emitters in the upper listbox and particle emitter in the lower listbox.
• Click at a location in the space to create a particle emitter. Right click when done.
• Click on the Play button to see the particle emitter working.

Get a Rain Drop Shape: right look, rotation and size

• • Double click the particle emitter to open up its property editor.
  • In the left listbox of the property editor panel, ensure the ParticleMaterial item is expanded.
  • Click on the Diffuse property in the left listbox. In the right listbox, ensure the DiffuseMap property is expanded. Hover your mouse over the Texture property, click new and then click Import Texture from File….
  • Select a raindrop picture from your files. 
• Look
  • In the left listbox of the property editor panel, click on the Translucency item. In the right listbox, change Blend Mode to Alpha blended. Move the Opacity slider to the desired value.
  • Click on the Refraction property and set Enabled to true. Move the Diffuse Blend slider to the desired value.
  • In the left listbox, click on the Diffuse property. In the right listbox, click on the Color property and select the desired color.
• Size
  • In the left listbox, click on the Particle Emitter icon. In the right listbox, click on Dimensions and then rotate the Size dial to the desired value.
• Rotation
  • In the left listbox, under ParticleMaterial, click the Diffuse item. In the right listbox, expand DiffuseMap and click on Rotation and change the Enabled property to true.
  • Click on the Menu button to the left of the Angles property. Click and drag (scrub) the z roller to orientate the raindrops.

Spread the rain out

• Undock the toolbox panel. In the upper listbox, click entities and in the lower listbox, click plane.
• Click and drag your mouse in the space to create a PlaneEntity. Right click when done.
• Double click the PlaneEntity to open its property editor.
• In the left listbox of the property editor, click on the Menu button (triangle) to the right of the RigidBody item and click Remove Attribute. This ensures the plane is invisibility and lets other objects pass through it.
• Click on the Menu button to the right of the TriggerActivating item and click Remove Attribute. This ensures the object won’t affect any Triggers in the space.
• Expand the MeshModel item from the left listbox and click on Materials. In the right listbox, click none for the Material 1 property. This makes the object invisible.
• Undock the hierarchy panel. Click and drag the ParticleEmitter onto the PlaneEntity. This makes a parent-child relationship where the ParticleEmitter is the child of the PlaneEntity.
• In the hierarchy panel, double click the ParticleEmitter to open its property editor.
• In the left listbox of the property editor panel, click on ParticleEmitter. In the right listbox, click on the Area property and set the Use Parent Surface property to true. This enables the PlaneEntity to emit the raindrops across its surface.

Make rain fall, at right speed. How rainy should it be?

• In the left listbox, click on the ParticleEmitter item. In the right listbox, click on the Physics property and use the Mass slider. This will give the raindrops mass so they will fall down.
• Click on the Continuous property to expand it. In the Pulse property row, click on ConstantPulse. In the Frequency property, scrub the roller to the desired value.