Hello,
I have been using Embergen and Liquigen for awhile and its great for a lot of things, but I often finding myself wishing I had a bit more control over the emitters. I like to create a shape to emit my source particles from to allow me to create an initial shape of the effect for the first few frames. I have been having trouble getting the same results in Embergen and Liquigen.
In Houdini, I had a setup that works for both gas and liquid simulations and it was quite versatile for bursts of all kinds. I start with a sphere or half sphere and I displace it with a noise modifier to get a spiky shape. I would then fill it with particles that are used as emitters for my gas or liquid simulation. All of this can currently be be done with both software by importing a shape mesh.
The key feature was the ability to add velocity to the particles based on their distance from the center of the object. The further away they spawned from the pivot, the higher their velocity along a vector away from the object pivot. This would make the particles expand outwards while maintaining the initial shape of the mesh. You could make the particles in the middle move hardly at all and the ones near the tips of the shape fly much further.
Behold my amazing MS paint example! 
This sort of setup provides much more flexibility for sculpting the first few frames of the simulation. It leads to more dynamic looking effects than simply spawning from a sphere or other simple shape and pushing the particles around with forces.
I have tried using the forces with falloffs and the force shape but the results aren’t quite the same. I’m using the shape force in Liquigen, but it appears to apply a force along the shapes surface normal.
I know this is probably a very low priority thing but it would be an awesome feature for both Embergen and Liquigen. Perhaps it could be part of the variable particle attributes that’s being worked on. If anyone has gotten close to this with existing tools, I would love to see your setups!
