# Mantaflow : Why is my fluid not showing up? / Why is my fluid going thourgh my mesh?

I wanna create a forest landscape with a river in it. I'd like to create the river using fluid physics, for realism and training purpose.

Here's my scene:

Pretty easy scene: my river bed is set as an obstacle, i have a fluid emitter (using flow -> liquid -> inflow) and a domain, displayed as wire and cache type set as Replay to see all those particles.

Here's the problem: mantaflow in kinda messy. I've tried simpler fluid simulation using only a cube and a similar fluid emitter following this famous tutorial (https://www.youtube.com/watch?v=JYc_6fXEjw4&list=FLX-jj-0Y_RabznBgbDa0rIQ&index=4&t=0s) ans it worked fine.

BUT whenever the domain differs from a simple cube (here, a rectangle), fluids just do not show up. Also, whenever obstacles differs from a basic mesh (like a uv sphere or cube), fluids just go straight through it.

I've searched a solution for quite a while, but apparently, all these simulations are sort of new, and there's not a lot of talk about it.

For the fluid going through problem, I've tried thicker meshes as obstacles, but it didn't change anything, i tried playing with the surface thickness parameter, same result.

For the domain problem, it's simple: if the domain is a cube, it works, otherwise, it does not. But also, it only works with cubes of a certain size? I dunnow, it's really messy.

Here's my blender file: https://we.tl/t-xhNQvjkwKU

So here's the question: How to make a fluid come from this sphere and use the -not so complex- mesh below it as an obstacle?

• Have you set up your obstacle as a collision effector (Fluid -> Effector -> Collision) in the simulation? Apr 25 '20 at 18:58
• I did, should've mentionned that, i'll edit. Apr 25 '20 at 19:59