isometric surface as temperature field

[cspears2002]

A colleague at work told me I can use an isometric surface as a temperature field to influence some smoke I'm trying to create, so I created an isometric volume and fed it into the Temperature SOP Path of my pyro object. However, I have ran several tests, I can't get the smoke to respond to the field. I want to create smoke that breaks up into a lot of wispy tendrils. Am I doing something wrong?

[Macha]

Do you mean a surface or a volume? I assume a volume because if you mean surface then there is no need for it to be isometric.

Create a volume (fog) and put it into the pyro object's Initial Data Temperature SOP. This will dissipate (used up?) very quickly and that is why you may not see an effect. (I don't know the reason why it does that)

So, if you want continous temperature control in a field, here is what you can do: Create a scalar sop field and give it the Data name "temperature".

hotbox.hipnc

[old school]

Ouch!

Now that is just downright cruel Macha!

Completely trouncing all temperature with your own field. I guess that is good to know if you want to build your own fluid solver that uses a fixed temperature field. That is why the smoke sinks to the floor when the temperature field rises away from the source. Not event the source temp is taken in to consideration.

To answer your question macha, putting the geo in to the sop field only references the temperature field on the first frame. That is why it seems to evaporate. It's only considered on the first frame of the sim.

See the attached file for a more gentile approach to adding a custom geometry scalar field to temperature (or any field for that matter).

I just used the Add Field To Fluid tool from the Volume shelf to a smoke container then modified the DOP network to suit. I also added an expression to control how much the custom field was added to temperature as that is a common "what next?" question.

With this method you can modify any field in the smoke or pyro solver with your own geometry. To get tendrils, you may want to add noise to the SOP volume primitive and animate that. Can use the Volume Mix SOP in user mode. Use expression like:

$V * noise($X*2,$Y*2+$T*6,$X*2))

Or use a Volume VOP and do whatever.

Note: It's best to feed DOPs world axis-aligned volume primitive. That way the SOP Scalar Field DOP doesn't have to rebuild a new volume sampling in to the SOP field. Separate your animated object from another object (no object Translates) that object merges the animated object and then Iso Offset this to a world axis aligned volume primitive.

add_geo_field_to_temperature.hip

[Macha]

Hey, thanks oldschool, that's a nice file with good explanation.