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Mesh Emitters
Document Summary: A reference to properties-based emitter editing and creation. (non UDN build). Document Changelog: Updated by Tom Lin for 2226 build and reorganization. Original Author: Lode Vandevenne.Introduction
This document will cover mesh emitters, one of four different possible emitters available in the 2226 build. For more information on general emitter properties, see EmittersReference. For more information on the other three emitter types, see SpriteEmitter, SparkEmitter and BeamEmitter. Mesh emitters are somewhat expensive, compared to the other available types. In some cases however, there is simply no replacement for a good mesh emitter. In particular, explosions that kick up debris are helped a good deal if some meshes bounce about post-impact. Also, rotation of particles in more than one plane of motion is best handled with mesh emitters, so tumbling actions will practically always demand them. There are a large amount of variables that control the behaviors of a mesh emitter. Most of these are covered in depth in the EmittersReference document. Fields of special interest will be pointed out in this document. The fields will be addressed in the order they appear in the properties window. (see image below)
Acceleration
You may want to use acceleration if you use a mesh emitter. Note that acceleration is just what it sounds like - the increase in particle speed over time. If you want your particles to move with a consistent speed, then you should be looking at the Velocity field. Also note that acceleration isn't given in a range of values, so all your particles will accelerate at the same rate. To get some noise into your particle motions, use varying velocities.Collision
When using mesh emitters, you will usually want collision enabled. One of the big advantages of using mesh emitters is that upon colliding with the world, the illusion of three-dimensionality is preserved, whereas it is often broken when using collision with sprites and textures.Color
This field affects mesh emitters, somewhat surprisingly. Simply change the multiplier values to change the color of your spawned meshes. Note, however, that you must go to the Mesh field and toggle the variable UseParticleColor to `true' to see the effects of your changes in this field.Fading
It's a good idea to use a relatively long fade out time with a mesh emitter, to avoid ugly popping.Force
This doesn't often need to be set with mesh emitters.Mesh
This is one of two fields that specifically affects only the mesh emitter type. There are only a few options to consider, but they tie into other fields, so it's not as simple as it first appears.


Use Mesh Blend Mode
If this is true, the blend mode of the mesh is used. This means that the particles will look just like they do when you drop them in the level. If this is false, the particles will use the blend mode defined in the texture category.Render Two Sided
If this set, the mesh will render all triangles two sided. This is useful only if UseMeshBlendMode is false.Use Particle Color
If this is set, the mesh will use the settings in the Color field. This is only useful if UseMeshBlendMode is true.MeshSpawning
MeshSpawning allows you to use a static mesh as a framework for spawning Emitters. The vertices in the static mesh are used to calculate emitter properties, such as velocity and color of the spawned particles. For more information, see the Emitter Reference doc.Revolution
You may want to add revolutions to your mesh emitter. For a more in-depth review of revolution, see the EmittersReference document.Rotation




Size






SkeletalMesh
Skeletal Mesh emitters allows you to attach particles to the bones of a skeletal mesh. The mesh is used to determine the spawn location of the particles and can also be used to determine the movement the particles. For a more in-depth review of Skeletal Mesh emitters, see the Particle Systems document.Spawning
Make sure to set appropriate values in the Spawning fields. These figures will affect how quickly particles are created, over the lifetime of your emitter. For a more in-depth review of Spawning, see the Particle Systems document.Texture




