Hey

I'm trying to get a custom velocity field in a pyro sim but can't seem to get it into the DOP-network.
After searching some forums, all I could find were either custom tools or files that were way more advanced than I can currently understand.
Or answers like “Use this here node, put it in your DOP and you're good”, but that didn't quite help me a lot.

I start with a tube, do an isooffset, scatter points in the volume and set the normals of those points to set the desired direction.
Then I feed the normal values into the velocity attribute.
To test it out, I create a Volume From Attribute SOP, using velocity, and use it to advect particles, which works.
Now I would like to get the motion that the particles seem to get, into some smoke (or gas, or fire, whatever works).
At the moment, my setup starts with a Fluid Source SOP in which I feed the points.
Then I read in that Fluid Source into a SOP Vectorfield DOP between the pyro-object and the pyro-solver or between the pyro-solver and the gravity node.
But wherever I place the SOP Vectorfield DOP, it isn't doing much for me (aka, I have no clue where to put that) and that's about as far as I've gotten.

Could anyone point me in the right direction?
Thanks in advance!


Eckxter

Normally I would dive inside the DOP Network and add another Source Volume node and add that one to the merge node but somehow this insanely slows down the simulation.

Then theres the alternative way which I also use quite alot, and thats by using a Field Force node in DOP and use a SOP Vector Field as input.
You might need to turn of the guide geometry because its quite heavy to compute most of the times.

Check out the attached file.

Thanks for the help Johnny!
I've gotten a little bit closer now.
I had to change the primitive numbers in the SOP Vectorfield DOP from 0|1|2 to 1|2|3 (0 was the density attrib).
By doing that I managed to make the smoke spiraling inward in the beginning, just like the velocity field tells it to do,
but after 20 frames or so it stops going inward for some reason.
Normally the inward direction changes at frame 96. Up until then, it should keep going inward.
So now I'm puzzling on that one.

I've also tried POPs in DOPs to see if that might give me some ideas.
But as it's my first time doing POPs in DOPs, I do not know how I can source from the particles that are already in the DOP in which you want it to source from.

This is one way that I use for applying DOP POPs as Pyro Source inside the same simulation.

Kind of an Inception going on here…..

Hope this helps!

I think I found how I can accomplish the effect I want.
There's a masterclass on building fluid solvers from scratch.
It seems that all the parts I needed are explained in there.

The next step is to actually get some smoke going on

Woot! I have the smoke movement to 90% of what I want it to be.
The master class helped a lot in finding the parts and ways to set it up.
Now all that's left is giving it some more wobbly/waviness to finish it up.
I'll do that after I get my shading done.

Thanks for the help!

Eckxter

(File in attachment for those of you who are curious)