AVEVA™ XR Studio

Snow

Save PDF

TABLE OF CONTENTS

Snow

Save PDF

Last UpdatedDec 16, 2023
4 minute read

The Snow node creates a snow effect.

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

For more information, see Snow 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

Heightmap or Drain

Usually, snow should not pass through solid objects.

The Snow node supports two different possibilities to determine where snow stops falling:

Height map
Drain

Height map

During loading time, an heightmap image is generated by the system. This map is generated 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 snow should disappear.

The precision of this approach relies on several factors.

Factor	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. It involves setting an absolute height at which snow drops disappear.

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

Code example

This is a code example for Snow.

Snow fields

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

Field inheritance: NodeBase > Snow

Fields	Type	Use	Default value	Description
emitterPosition	svec3	Optional	0 0	Emitter position. This is used when followRenderCamera is false.
enabled	sbool	Optional	true	Enables/disables the snow effect.
followRenderCamera	sbool	Optional	true	When enabled, the emitter position moves each frame to match the Camera used for rendering.
forcesMultiplier	sfloat	Optional	0.73	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 could be empty until the particles fall down). Resets the simulation.
frameZeroYRange	sfloat	Optional		The Y range where the particles are spawned 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 three dimensions.
maxParticles	sint	Optional	42000	Maximum number of particles available for the simulation. Should not be changed in runtime. Resets the simulation.
mode	senum	Optional	heightmapRT	Specifies mode as drain or heightmapRT.
numParticles	sint	Optional	42000	Number of particles to be processed and rendered. Must be less (or equal) than maxParticles.
opacity	sfloat	Optional	1	Pixel opacity.
particleWidth	sfloat	Optional	0.0316	Width of the rendered particles.
particleYAspect	sfloat	Optional	1.55	Y aspect ratio of the rendered particles (Y= Width x YAspect).
randomForceRange	svec3	Optional	2 3 4	Additional force added randomly to each particle. X and Z component 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_snow	No default	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 be used for each pixel of the heightmap texture among U8,U16,F16 and F32. Larger formats allow more precision. Use float formats only when there is a large range of different heights.
textureSize	senum	Optional	1024	Selects heightmap texture size among 512,1024,2048 and \\4096\\.
wind	svec3	Optional	3 0 1	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

Snow

Table of Contents

Snow

Platform support

Heightmap or Drain

Code example

Snow fields

In This Topic

Related Links