I thought I´d post an update of my RND progress. I am still having problems getting Renderman to render my VDB files from Houdini and so far nobody was able to help me. So this is an example of the VDB file rendered in Arnold. It is obviously not yet production quality, but I think it looks quite good. There are some issues with density falloff/breakup at the edges of the explosion and especially towards the end, when it starts to dissipate. I am going to do some more tests with more whyspy and faster dissipating smoke.
I have been experimenting with volumes that are based on a liquid simulation. There is some gasoline exploding in my film, so I wanted to test a way to achieve that.
This is the underlying liquid simulation for the explosion above. I used an alembic to bring it into Maya and rendered with Arnold.