Hi. I’m very new to fluid simulation. How can I achieve the exact effect as this: https://www.youtube.com/watch?v=-2fKksOc638
If you watch it at .25 playback speed, you’ll see that it’s emitting from a sphere and the explosion seems to be going upwards and outwards.
I did some testing and found a way that seems promising:
1-First make a simple simulation with a falling sphere of water.
2-Put a “force” object in the middle of the sphere. Lower it a bit so the water gets thrown mostly upward.
3-In the domain’s settings, go to the “fields weights” section and animate the “force” influence slider so it only has an effect on the first frame of the explosion. I tried to animate the strength of the force object itself, but it didn’t seem to use the animation.
4-Adjust the strength of the force object so the explosion has the desired size. You can also deform the water emitter a bit to make the explosion more random.
5-You will need better mesh generation settings than the defaults if you want the full detail of the droplets. Set the upres factor to 3, the particle radius to 1.5 and check the speed vectors box (motion blur always makes water look more realistic).
Then, the render settings will need some attention, because rendering a bunch of droplets correctly is difficult. Assuming you are using Cycles:
-Set the glossy, transmission and total bounces to something decently high, like 16 each.
-make sure caustics are active, both reflective and refractive.
-Set the filter glossy to 0.5. It’s a value that will give just enough blurring to the caustics so that they don’t look like a noisy mess.
-Set the “clamp indirect” to 50. The default of 10 is good enough for most scenes, but caustics could use more.
Then, the water material:
-Use a glass bsdf set to pure white. If you want to color the water, use a colored volumetric shader rather that coloring the water’s surface.
-You may want to deactivate the shadows on the water if it looks too dark. Either do it on the object itself, or use the “light path” node in the material.
Hi. Thanks for helping me out. I’m having some issues with this. Sorry it took me a couple of weeks to get back to this (been busy with work). I only got up to step 4 and I can’t seem to get the the shape of the explosion right.
Here are my settings:
Force Shape: Point
The force is positioned slightly below the fluid but still in it (in other words the force is not centered in the fluid). You can see this below.
When force strength is at 75:
https://imgur.com/a/fUsKza5
When force strength is at 150:
https://imgur.com/a/rZTXzFt
I keyframed the Domain-FieldWeights-Force value from 1 to 0 in frame 1 and 2, respectively.
I haven’t touched any other settings other than:
and the start and end frames.
And I guess the only thing I did differently is I placed the fluid and force at the bottom of the domain kind of like in the reference video (instead of having the fluid fall, like you suggested).
Do you by any chance still have the blend file? While experimenting, I noticed both the positions of the force and the fluid shape (as well as the force strength) have a major impact on the shape of the explosion.
Edit: Here’s when the fluid is positioned in the air with a strength of 75:
https://imgur.com/a/ApU2pwx
and with a strength of 150:
https://imgur.com/a/4MhSdqw
I also am placing the fluid at the bottom, I just meant it like: create a basic water sphere simulation.
The main thing you have to do is to place the force object more towards the inside of the water. Place it barely under the middle of the water sphere. You will probably have to readjust the strength.
Other things I would like to add after testing a bit more:
-You can get a more chaotic looking explosion by adding a turbulence field. I treated it similar to the force field, but made it last a few frames. If you don’t add turbulence, the explosion will look way too symmetrical.
-I also distorted the water emitter to break the symmetry.
-If you want motion blur (more realistic, much longer render), you have to set the cache format to “uni cache”, the default openVDB doesn’t work.
-Resolution is important and will greatly alter the look.
Here is the file, make sure to set the cache’s path before baking.
water_explosion.blend (1.1 MB)
