Is it possible to emit particles off a surface based on a material/texture map?

[worldyum]

Hello,

I was just wondering if it's possible to emit particles off of the surface of an object based on a material and/or texture map? I know you can do this in Max and Maya with a gray-scale map but is it possible in UDK?

Thank You,
Bryan

[Marvin.Star]

I am going to say yes; because in UDK code you can find a class called UTPawnSoundGroup which dependson(UTPhysicalMaterialProperty) that is used to detect what surface it is on and plays different sounds for steps and projectiles. Check that out and you may be able to figure out how to script a version for particles. Also I think that the pawnsoundgroup is either used in UTPawn or UTMusicManager.

[ambershee]

http://udn.epicgames.com/Three/PhysicalMaterial.html

[worldyum]

Physical Material is different

http://udn.epicgames.com/Three/PhysicalMaterial.html

Thank you guys but a physical material as far as I know is different. Although a physical material will allow me to call different particle effect and different sound based on the material type (rock, sand, etc.) what I'm looking for is a way to emit particles off of a single object (sphere for example) based on a gray scale map, so where the map is white 100% of the particles I want to emit will be emitted, 50% where it's gray and 0% where it's black. Kind of like a displacement map, but instead of displacing the mesh, emit particles.

[ambershee]

No, you can't do that.

[Marvin.Star]

I can't say there is an easy way to do it; however, I'm sure that with some intense coding it would be possible. Try asking this question in the Unrealscript area. Or you could do it the simple way: Create the particle you want to emit 100%, create a copy reduce the opacity of the particle(you could create a separate material to reduce the opacity or do this in the emitter itself). Place this second one where you want lower opacity, and so on until you have a satisfactory gradient. But don't over do it, I doubt you would want more than three.

[ambershee]

You can't access any real texture information in UnrealScript, so there's no amount of programming that will work in this case.