Travis Harkleroad

1) the DOP import SOP pulls in the data that already exists in your DOP network. In the node, you specify which DOP object you wish to copy the data from and what data you want to copy. For example, if I was pulling my FLIP fluid particles in from a DOP simulation. In the DOP import node, I would specify that I want to get information from the flip fluid object (by default this is usually named “fluidfluidobject1”), and the data that I want to copy, which is Geometry. Geometry in this case being the name in DOPs for the FLIP fluid particles.



The DOP import just pulls information from the DOP network, so if you advance a timestep and the DOP network hasn't cooked, the DOP import will cause that DOP network to cookm unless you have disabled simulations.

2) The simplest way to pull SOP geometry into DOPs is with the SOPgeometry node. This node asks that you specify the path to the SOP you want to import. You can use this data to calculate forces, masks, scalar/vector fields, etc.

If you want to do something as specific as having each DOP object follow a different point on a sphere, you can use a SOP solver. The SOP solver create a SOP network inside of your DOP network that is evaluated at each time step. This lets you use SOP nodes to influence your DOP simulation during the solve.



inside the SOP solver, you have just a regular SOP network. By default it puts down several DOP imports that bring in your DOP simulation information. These are the same nodes that you put down at the normal SOP level, the only difference is that they are evaluated at every timestep and the output is then piped back into the simulation. So you could have your animated sphere inside your SOP solver (or bring it in with an object merge), and you could set the velocity of your RBD points to point towards a specific point on the sphere.



Alternatively, you could use a VOP force DOP node (which allows you to use all of the awesome VOP nodes you'd have in a VOP SOP) to create forces in DOPs. You could have create a force that brings in the appropriate point on the sphere and then creates a force towards that point.

Hello,

it isn't super clear what you want to do in this file. I'm assuming that you want to create some sort of fractured geometry that is similar to the shape of the ground geometry.

Using the cookie sop to do this is inadvisable for two reasons: 1)You're only going to get one piece that is either the union or intersection of the two geometries and 2) your ground plane is just a flat plane; the cookie SOP can't determine what is “inside” or “outside” of the intersection of two geometries when one of them is just a flat plane. If you make the ground plane a 3 dimensional shape, then you can use the cookie SOP, but it still wouldn't give you “fractured” geometry.

The easiest way to get fractured geometry is to use the voronoi fracture SOP, which takes geometry (the wall in your case) and points to use to create fracture pieces. The seed points determine where you get more fracture pieces, meaning that if you have a lot of seed points in one spot, you will get a lot of small fractured pieces there.

If you take a look at the HIP file I've attached, I used a sphere to place a bunch of points right above your ground plane. I then use those points as the seed points for the voronoi fracture SOP. This produces a lot of small pieces only above the ground.

You can then take this into DOPs and simulate the wall breaking apart, but that requires some further set-up.

You aren't supposed to add the velocity to the source FLIP points, that only gives them an initial velocity. You want to add the velocity attribute to another object and then bring that into DOPs using the SOP geometry node. That insures that they will be given a constant swirling force.

The way that you have your field force node set up, it's not really doing anything because you're not giving it any information to use to generate the force. You don't have anything going into the green input on the right side of the node.

The FLIP source and force that swirls the particles are two separate objects. I've attached an example HIP with some stickies. Hopefully that clears things up.

Also, I enabled viscosity in my examples to keep the fluid together.