Applying Cached Post Sim Effects

The Lagao Cached Post Sim compounds let you apply a variety of effects on top of a Lagoa particle simulation. For example, you can add bubbles and debris to a fluid effect.

The compounds are designed to be applied on a point cloud that is reading from a cache created by a Lagoa simulation. You can:

• Create a cached cloud (see Creating a Cached Lagoa Cloud) and then apply Cached Post Sim Effects to it (see Applying Post Sim Effects to Cached Clouds).

• Choose a Cached Post Sim Effect and have it applied to a new cached cloud that is automatically created (see Applying a Cached Post Sim Effect to a New Cloud). You can continue to apply additional effects to the cloud (see Applying Post Sim Effects to Cached Clouds).

If you want to change the simulation later, you will need to re-write the cache files from the original cloud after you are done. The cached clouds will automatically use the updated cache files.

Types of Cached Post Sim Effects

The following Cached Post Sim Effects compounds are available:

Delete by Density removes points based on how their density compares to a given value. It requires that density calculations are enabled in the Lagoa simulation. For a description of the available options, see Lagoa Delete by Density [ICE Reference].

Advect Points has options for removing, duplicating, and stretching points to simulate bubbles and debris in a fluid. For a description of the available options, see Lagoa Advect Points [ICE Reference]. See also Important Considerations When Advecting Points.

Density Color Gradient sets particle color based on density. You can then transfer the color to the polygonized mesh to create various effects. This compound also requires that density calculations are enabled in the Lagoa simulation. For a description of the available options, see Lagoa Density Color Gradient [ICE Reference].

Duplicate and Stretch clones points and moves the copies along their velocities to give the appearance of stretching. It is best applied to clouds that have already been thinned, for example, using Delete by Density. For a description of the available options, see Lagoa Duplicate and Stretch [ICE Reference].

Point Duplicator clones points and jitters their positions to create larger or more irregular shapes. It is also best applied to clouds that have already been thinned. For a description of the available options, see Lagoa Point Duplicator [ICE Reference]/

Velocity Color Gradient sets particle color based on speed. For a description of the available options, see Lagoa Velocity Color Gradient [ICE Reference].

Creating a Cached Lagoa Cloud

1. Select a point cloud that has a Lagoa effect.

2. If you have not already written cache files for the cloud, do so now by choosing Particles > Simulation > Save Cache on Selection from the ICE toolbar.

3. Choose Particles > Simulation > Load Cache from Selection.

A new point cloud is created and set to read from the original cloud’s cache files. The original cloud is hidden automatically.

Applying a Cached Post Sim Effect to a New Cloud

1. Select a point cloud that has a Lagoa effect.

2. If you have not already written cache files for the cloud, do so now by choosing Particles > Simulation > Save Cache on Selection from the ICE toolbar.

3. Choose an item from the Particles > After Emission > Cached Post Sim Effect menu. See Types of Cached Post Sim Effects.

4. When prompted, choose Create a new cached cloud from selection and click OK.

A new cloud is created, the cache files are loaded, and the Cached Post Sim Effect compound is applied. The original cloud is hidden automatically.

Applying Post Sim Effects to Cached Clouds

1. Select a point cloud that is already reading cache files from a Lagoa effect.

2. Choose an item from the Particles > After Emission > Cached Post Sim Effect menu. See Types of Cached Post Sim Effects.

3. When prompted, choose Selected cloud is already cached and click OK.

The Cached Post Sim Effect compound is applied in a new ICE tree.

Important Considerations When Advecting Points

There are some important things to consider when using the Lagoa Advect Points compound. If you are using it to create bubbles or debris inside a polygonized fluid, then you typically want to remove points that are outside the mesh. However, you cannot use Lagoa Advect Points on the same cloud that is being used to generate the polygonized mesh because it would create a dependency cycle.

There are two ways around this:

• Using three clouds is easy, but requires more points in the scene.

• Using two clouds requires fewer points but involves a bit more clicking around to manage the caches.

Using Lagoa Advect Points with 3 Clouds

1. Use one cloud to create a Lagoa effect. Write out cache files (Particles > Simulation > Save Cache on Selection from the ICE toolbar), and keep it hidden to prevent it from resimulating whenever you change frames.

2. Create a cached cloud from the first one and polygonize it to create the outside surface of the fluid. See Meshing Point Clouds (and Other Things) [Polygon Modeling].

3. Create another cached cloud from the first one and apply the Lagoa Advect Points compound. Activate Remove Outside Polygonizer and connect the polygonized mesh generated from the second cloud.

Using Lagoa Advect Points with 2 Clouds

1. Use one cloud to create a Lagoa effect. Write out cache files, then set it to read from the cache files and lock the cache (see Caching Animated Deformations and Simulations [Data Management]). Create a Polygonized mesh from this cloud.

2. Create a cached cloud from the first one and apply the Lagoa Advect Points compound. Activate Remove Outside Polygonizer and connect the polygonized mesh generated from the first cloud.

 

 



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