Advecting "gradient" Field of Heightfield?

[adamknauer1]

Hey guys wondering if anyone can give me some ideas to tackle this effect on a heightfield: https://twitter.com/Jose_Molfino/status/1669804412569567233 The artist Jose says that it's a heightfield expanding inside a solver and a gradient field based on height is used for advection. Does anyone know how that works? How would you advect calculated values like gradient field vectors?

 

Thank you!

Edited March 28 by adamknauer1

[Librarian]

@adamknauer1 Try this ..gradient,divergence, curl, height and water , after when you are done in DOP, just import fields with SOP primitive properties and Play with different fileds, then check your LINK you have Nice tricks .. Have fun



 

[adamknauer1]

Hello,

@LibrarianThank you for the help! Is this sort of how the shallow water solver works?

Edited March 28 by adamknauer1

[Librarian]

@adamknauer1 Basically Yes , just here you have more View(somehow not complicated to see at least for me)  , easy to control and you can adjust height , different PIC and various ways to manipulate fields.

if you search I posted also Espresso  Blend Fluid  that have nice tricks.. so combining those 2 you can make Nice effects .
 

[adamknauer1]

@LibrarianOk I appreciate the advice here. I will take a look at that post as well!!

[adamknauer1]

@LibrarianDo you have that hipfile so I could dive in and see what's going on? Thank you!

[Librarian]

@adamknauer1 
You want to say that you don't have 30 minutes of your time to just create Dop (just Node DOP) and rewrite those codes.

ccccc Adame Jabuko moja

https://www.sidefx.com/forum/topic/95230/

 

Edited March 29 by Librarian

[animatrix]

Hi,

Here is one way:

1. Compute grad using VEX in a Volume Wrangle:

v@grad = volumegradient ( 0, "height", @P );

2. Advect using Volume VOP SOP inside Solver SOP:

3. Run the simulation

 

You can also get different results by playing with the advection vector:

v@grad = volumegradient ( 0, "height", @P );
vector up = { 0, 1, 0 };
vector tangent = cross ( v@grad, up );

v@grad = tangent + v@grad;

 

v@grad = volumegradient ( 0, "height", @P );
vector up = { 0, 1, 0 };
vector tangent = cross ( v@grad, up );

v@grad = tangent;

[adamknauer1]

@animatrixThank you! What is the structure inside of your Solver Sop? Is there just a volume vop?

Edited April 1 by adamknauer1

[animatrix]

5 hours ago, adamknauer1 said:

@animatrixThank you! What is the structure inside of your Solver Sop? Is there just a volume vop?

Yes only Volume VOP SOP.

[adamknauer1]

@animatrix hmm I'm not getting any advection results. Must be missing something I'm missing. Should I be using any of the inputs into the geometry file inputs?

[Librarian]

https://cmolfino.gumroad.com/

[animatrix]

4 hours ago, adamknauer1 said:

@animatrix hmm I'm not getting any advection results. Must be missing something I'm missing. Should I be using any of the inputs into the geometry file inputs?

Do you have the gradient field and you use the right input in advect by volume VOP?

[adamknauer1]

@animatrixI have a gradient field, should it match the bounds of the heightfield that I am advecting? Should this "gradient" field have initial values? I am currently inputting the previous frame into the advect by volumes.

[animatrix]

Yes if gradient is empty then it won't do anything. In my code you can see I am computing it using volume wrangle.

[adamknauer1]

@animatrixI'm confused why my setup isn't working;/ If you don't mind me asking, what is the correct input for the volume advect vop? Thanks!!

[animatrix]

I think it would be easier if you could attach your file.

[adamknauer1]

@animatrixOk I think you're right 

Edited April 11 by adamknauer1

[animatrix]

I see the issues, you need to have the grad field the same as your height field:

But most important thing is to use a non-zero Timestep value:

Then it works.

[adamknauer1]

@animatrixAhhhh I see. Makes sense why it wasn't working! Thanks for all your help here!!!