Fluid not interacting with model

08/02/2023 1:27 am

Hello! I just had a chance to take a look at the Blend file.

It appears that there are some non-manifold geometry issues with the objects. This could potentially result in unexpected behaviour within the simulator, but sometimes may not cause issues. Tip: Blender's built-in 3D-Print Toolbox addon can be useful for detecting and highlighting these types of geometry issues (more info).

It looks like the main issue that is causing the liquid to not interact with the obstacles is due to thin walled geometry. The simulation runs on a grid where the domain resolution controls how detailed the grid is. If obstacles are too thin, they may not be completely resolved on the simulation grid and fluid will not interact with these parts of the object. The solution in this case would be to increase the resolution. The thinnest obstacles should cover at least one grid voxel in order to show up in the simulation. More information can be found in these topics:

What is the simulation grid? - Info about the simulation grid and how to visualize the grid and voxel size.
Scene Troubleshooting: Thin Obstacles, Leaking Fluid - Tips for handling thin obstacles.

Tip: When there are many obstacles, or when there is a complex obstacle setup, the addon's "Obstacle Debugging Feature" can be helpful for visualizing how the obstacles are being resolved in the simulator. For example, this is a visualization when all objects are set as an obstacle at a resolution of 450 (image attached). Due to the thickness of some walls, a relatively high resolution is required to resolve these features.

Hope this info helps! Let us know if you have any questions.

obstacle_debug.jpg