AVEVA™ XR Studio

Rain

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Rain

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Last UpdatedFeb 21, 2024
4 minute read

Use the Rain node to create a rain effect.

The characteristics of rain can be modified at run time.
There can be just one snow node per project.

For more information, see Rain Particles Renderer.

Platform support

This node is supported on XR-Windows platform only.

XR-WIN	XR-P-WIN	XR-P-IOS	XR-P-AND	XR-P-WASM
Full support	No support	No support	No support	No support

Code example

This is a code example for the Rain node.

Heightmap or Drain

Rain should not typically pass through solid objects.

The Rain node supports two options to determine where rain stops falling:

Height map
Drain

Height map

At load time, the system generates a heightmap image by positioning a special camera at the top of the scene.

The heightmap box (heightmapCenter, heightmapSize) defines the area to be included in the heightmap texture calculation.

For each pixel of the map, it is defined at which height the rain should disappear.

The precision of this approach relies on several factors.

Parameter	Description
textureSize	Larger maps are more precise because each pixel covers a smaller area.
textureFormat	Increasing pixel format increases precision.

Drain

The Drain approach is simpler and involves setting an absolute height at which rain drops disappear.

You can use this method in landscapes where there are no high structures.

Rain fields

These are the fields for Rain node. Only the node-specific fields are indicated, not fields obtained by inheritance.

Field inheritance: NodeBase > Rain

Fields	Type	Use	Default value	Description
emitterPosition	svec3	Optional	0 0 0	The emitter position. This is used when followRenderCamera is false.
enabled	sbool	Optional	true	Enables/disables the rain effect.
followRenderCamera	sbool	Optional	true	When enabled, the emitter position moves each frame to match the camera that is being used for rendering.
forcesMultiplier	sfloat	Optional	1	Scales all the forces in the simulation. Can be used while tweaking forces. Resets the simulation.
frameZeroAutoPopulate	sbool	Optional	true	Populates the simulation with random particles on the first simulation frame. Otherwise the particles start from a simulated position. But the screen may be empty until the particles fall down. Resets the simulation.
frameZeroYRange	sfloat	Optional	10	The Y range where the particles spawn if frameZeroAutoPopulate is true. It is relative to the emitter position. Resets the simulation.
gravity	svec3	Optional	0 -9.8 0	Gravity (or main force).
heightmapPosition	svec3	Optional	0 0 0	Defines the center of the area handled by heightmap.
heightmapSize	svec3	Optional	100 100 100	Defines the size of the heightmap box on the 3 dimensions.
maxParticles	sint	Optional	30000	The maximum number of particles available for the simulation. You should not change this value during runtime. Resets the simulation.
mode	senum	Optional	heightmapRT	Specifies mode between drain and heightmapRT.
numParticles	sint	Optional	30000	The number of particles to be processed and rendered. Must be less than or equal to maxParticles.
opacity	sfloat	Optional	1	Pixel opacity.
particleWidth	sfloat	Optional	0.05	Width of the rendered particles.
particleYAspect	sfloat	Optional	20	Y aspect ratio of the rendered particles (Y= Width x YAspect).
randomForceRange	svec3	Optional	0.4 -4 0.4	Additional force that is added randomly to each particle. X and Z components have a random range from -range to +range. Y component has a random range between 0 and range. Resets the simulation.
shrinkMinValue	sfloat	Optional	0.3	Minimum shrink value that the particles can have (otherwise they would disappear). Particles shrink when viewed towards the direction of the camera. This way when looking up (or down) the particles appear less wide. 0 means full shrink, 1 means no shrink at all.
spawnRadius	sfloat	Optional	100	Particles spawn radius (X and Z components).
spawnY	sfloat	Optional	5	Particles spawn Y (relative to the emitter position, Y= emitY + spawnY).
spawnYRandomRange	sfloat	Optional	2	Particles spawn range on the Y axis.
template	sstring	modules/physx/template_rain	Not set	The name of the template particle system loaded as parameter starting point. It can be set at runtime to change the particle system settings.
texture	sstring	Optional	Rain.png	Name of the rain drop texture used for the effect.
textureFormat	senum	Optional	U8	Defines the precision to use for each pixel of the heightmap texture as U8, U16, F16 or F32. Bigger formats allow bigger precision. Use float formats only in case there's a big range of different heights.
textureSize	senum	Optional	1024	Selects heightmap texture size among 512,1024,2048 and \\4096\\.
wind	svec3	Optional	0 0 0	Additional force.
yDrain	sfloat	Optional	0	The Y value where the particles die. (drain and heightMap cannot be used at the same time).

AVEVA™ XR Studio

Rain

Table of Contents

Rain

Platform support

Code example

Heightmap or Drain

Rain fields

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