Ask : Simulation

Owned by thomas (Unlicensed)
Last updated: 03 May, 2018
3 min read
There is no significant boost in simulation speed with enabled GPU support. Why?

Dyverso is optimized for multi-core and many-core CPUs, but some GPU cards do not have enough computational power to outperform a modern 8 core or 12 core processor.

Gaming cards like the GeForce GTX 10 series are perfectly suited for Dyverso and perform very good. The typical speed boost is around 4x compared to CPU simulations.

For more information visit → "GPU-Acceleration" or "→ "Ask : GPU-Acceleration".

The mesh is not created where the particles are. Why is there is an offset between mesh and particles?

There are some cases where you will see an offset between mesh and particles:

  • The "Scene" tree object has been shifted with the the parented "Mesher" node after the particle simulation. To fix this, detach the "Mesher" or reset the "Scene" object to its original position.
  • With some MoGraph objects ("Cloner", "Array", and "Matrix"), RealFlow | Cinema 4D evaluates transformations and applies them to the "Scene" and "Mesher" nodes. This may result in an offset. 
Particles are not influenced through daemons or other fluid containers. What's happening?

In many cases, the links are established automatically by RealFlow | Cinema 4D, but there are also occasions where you have to connect interacting nodes.

Take a look the "Scene" and "Links" fields of the nodes involved:

  • If "Scene" and/or "Links" are empty the node will not be affected by other scene elements.
  • Specify the interacting nodes and "Scene" through drag and drop.
I have applied an object to the "Object" emitter, but there is no emission. What's wrong?

When the body's polygons are very small it might happen that you will not get any particle emission. To fix this, increase the "Fluid" container's "Resolution" to create more particles. You may need very high settings (> 100 or more).

I'm a RealFlow | Cinema 4D 1.0 user. Is it possible to use my simulations in 2.0 as well?

Yes, 1.0 scenes can be used with RealFlow | Cinema 4D 3, but there are a few things you have to consider:

  • The RPC format for particles is no longer supported and cannot be loaded or processed. RealFlow | Cinema 4D now uses the Alembic format.
  • Mesh Alembics are still valid and can be used with version 2.
  • Initial states are no longer valid, because they are also stored in the old RPC format.
  • Simulation settings from version 1 are set to "Auto".
  • Simulations with the "Liquid - PBD" particle type will be slightly different due to new fluid parameters.
I only have a few particles in the scene, but I need more. What can I do?

The number of particles depends on several factors:

  • Resolution. Every fluid, rigid, and elastic container has its own → "Resolution" parameter. Higher values create more particles.
  • Emission area. Particles are created within a certain area or volume define by the emitter. If this area is very small the amount of particles will low as well.
  • Emission speed. Many emitters have a "Speed" value to control the particles' initial velocity. With 0, the emission stops and the higher the "Speed" value, the more particles you will get.
How many particles are enough for a simulation?

This question cannot be answered globally, because the amount of particles strongly depends on the scene. A general rule is: the more, the better. More particles mean more detail, better splashes, and a believable fluid behaviour.

Several hundreds of thousands of particles are absolutely normal and can be simulated very fast with Dyverso's → GPU options. Even several millions of particles are not problematic and often required for mid-scale scenes.

I see exploding particles when they interact with objects, for example when I try to fill a glass. What's going on?

RealFlow | Maya works with adaptive substeps by default and this means that RealFlow determines the actual number of substeps. When particles settle, the number of substeps decreases, and this means less precision. As a consequence physical effects inside the fluid start to accumulate until a "pop" occurs. After the explosion the particles settle again, and RealFlow increases the number of substeps - the beginning of a new cycle. To avoid this effect increase the number of → "Min Substeps" and/or → "Min Iterations".