gasbuildrelationshipmask microsolver

[cupoftea]

hello.
i am trying to understand the "gasbuildrelationshipmask" DOP-microsolver. i read the documentation multiple times but i still cant figure out what it is doing or at least what can be done with it exactly.
as far as i understood it (can) go in conjunction with the source relationship DOP but also here, dont know how to use it ecxactly. 
thanks in advance! 
 

[Pazuzu]

This microsolver helps you to define a field mask using standard DOPs relationships (using the merge DOP for example). You can define for example a source object mask to emit fuel or density using just relationships, so if you have many objects and connect those besides the smoke solver with a merge using source relationship mode, the gasbuildrelationshipmask will create a field representing the objects as a fog or SDF representation. Attached is an example file (one hip is better that a thousand words )

Cheers

Alejandro

gasbuildrelationshipmask.hip

[cupoftea]

great such detail explanation from you as always Thank you.
i checked the file. looking at the green "source relationship" nodes and reading the documentation, merge says "affected (right) will use affectors (left) for creating density". 
so the smokeobject (right input) uses green sphere object (left input) as a density source, and the green "gasbuildrealtionshipmask__source" node is a mask?
right?
if right, what object or field does the "gasbuildrealtionshipmask__source" use as a mask?  it says "mask field source" and "reference field density". but how can the source at the same time be the source for density and mask for density? 
no?
thank you again
 

 

 

[Pazuzu]

56 minutes ago, cupoftea said:

so the smokeobject (right input) uses green sphere object (left input) as a density source, and the green "gasbuildrealtionshipmask__sourc

The Smoke object is just the container of data (In DOPs is very important that you have a container where all the data will be for DOPs to process) that contains all the necessary fields that the smoke/pyro solver will use to make the sim evolve by the DOPs engine.

56 minutes ago, cupoftea said:

if right, what object or field does the "gasbuildrealtionshipmask__source" use as a mask?  it says "mask field source" and "reference field density". but how can the source at the same time be the source for density and mask for density? 

In the file you will find two main colors to identify the relationship type, there are two in this case, a source relationship (green) and a sink relationship (red). So all the colored nodes makes each relationship works, for example for the source one, you need a merge DOP that will define the type or relationship as a source, then you need the object to generate the mask from (sphere) and finally the microsolver that will generate the mask field for your relationship (gasbuildrelationship__source). 

Regards the "reference field density", is a parameter of the node to generate the mask as a "fog" field, by default the node creates SDF representations.

Cheers!

Alejandro

[cupoftea]

thanks again Pazuzu. 
so that means in this case: the (green) sphere acts as a mask for the smoke?
correct?

 

[cupoftea]

or let me ask differently:
i checked your file and think i understand, but since it is "static" (non-simulatued, since no solver), i have no idea what would it look like when simulated?

thanks a lot again

 

[Pazuzu]

On 6/30/2017 at 2:34 AM, cupoftea said:

or let me ask differently:
i checked your file and think i understand, but since it is "static" (non-simulatued, since no solver), i have no idea what would it look like when simulated?

thanks a lot again

 

Yes, its just a static mask, because the field is overridden on every timestep as the relationship is active, but you can use that mask to source into a dynamic field (Density, Divergence, Temperature, Fuel, etc).

Cheers!

Alejandro

[cupoftea]

thx again, Alejandro
can you give a practical example of what you would use it for? just an example for me (still houdini new) to understand what you would use it for?
thank you