Download HDA – version 1.2
Download example HIP

This tool takes in points that you would like events to happen on and allows you to either manually or procedurally setup animated scaling sources over a range of time. It outputs the source geometry and center points with ‘cluster’ attributes for use in DOPs. I built this tool for a scene that needed a bunch of explosions randomly occurring, and I’ve also used it for giant bubbles.

For the procedural method to work start with a bunch of potential sources. The different sources each need a unique point ‘id’ attribute, in this case I set it as @ptnum on the original points which then transfers through the Copy SOP.

Then I append the HDA to the Copy SOP and pretty much leave all the parameters for now.

The results are animated sources with varying sizes and lengths of animation between the First and Last Frame (1-100). On the first frame of each source you can see the container preview box, the containers only need to exist for 1 frame with this clustering technique.

These sources now can be used with the Fluid Source SOP set to Stamp Points, and with Point Partitioning enabled.

Instancing also needs to be enabled inside the DOP Network on the smokeobject. It needs to be set to Continuous so that it keeps checking for points to instance containers onto every frame. The GasResize node is used to have the containers size update with the simulation, the delay needs to be set to 1 so that the containers have a chance to pick up the source.