Help Obi Fluid Not Working with Transparent Glass

[josemendez]

I am curious why Obi has not posted a real scale example for folks to see?  Can this be provided to validate that it does actually work in normal scale and help people set it up if it is as easy as changing the resolution?  Something simple like just a glass of water or the faucet demo in normal scale?

There's no such thing as "normal" scale, it all depends on what exactly you are trying to simulate and its relative size to other things in your scene. This being said, Obi uses real-world units for all quantities (sizes in meters, mass in kilograms, force in newtons, etc..).

I've had no problems at all when trying to bring down the size of fluid particles using either approach (increasing particle resolution, or using local-space mode and scaling the whole thing). The latter might be preferable if you wish to work at a very small scale or far away from the scene's origin, because it helps retain floating point math precision (since simulation is performed in solver space, and the results then scaled up/down).

The local space work around seems to defeat the purpose to interact with the rest of the scene.

When simulation is performed in local space, collisions and interaction with other objects in the scene happens as usual (colliders are internally expressed in local space too) so I don't see why would it prevent interaction with the rest of the scene?   Also I would not consider it a "work around", but a very valid (and often the only) way to precisely control the position/rotation/scale of a simulation in your world.

Here's a video of the bucket/faucet scene. I simply duplicated the faucet (made it 15 cm high), the emitter, and fluid material. Then set the material's resolution to 1000, left all other parameters intact. The FluidRenderer has been disabled and fluid is rendered using the ParticleRenderer to make it easy to see the size of particles. Works fine for me, maybe you can be a bit more specific about your setup?