new body force explanation

hello

seems to be what I need but have no explanation what each value changes…


can you explain it a bit more?
I need to make something like this http://c2n.me/3sTXmQe.png
we have tried to find a solution some months ago.
will it work with the new body force?

best regards
themaxxer

well, i will give you the force description, but i can’t see how can you use it to get the desired effect. it looks like kind of underwater source

Body (MXS: body) The geometry object used as attractor.

Strength (MXS: strength) The force intensity, this parameter affects mostly the points outside the body. The fluid accelerates constantly toward the force until reaching the body.

Max Distance - the distance where the force disappears
Fade Start - the distance (relative to max distance) where the force starts to decline

Suppress orb. (MXS:orbitsupp) Drag force suppressing the velocity components different from the direction toward the body. This force is pronounced outside the body.

Internal damp (MXS:veldamp) Damping the velocities above certain value (Damp min vel) inside the body, this parameter is used to prevent the escape of the fluid caused by the inertia, if the internal damp is zero, the fluid attracted to the body will continue across it.

Damp min vel. (MXS:dampstart) The threshold velocity for the internal damp force. This parameter is used to prevent total freezing of the fluid inside the body, it must remain “alive” having some residual movement.

thanks for reply…
so for what effect is the body force invented? have you an example?

best regards
themaxxer

it’s used for liquid shape and morphing, for example this video PHOENIX FLIP - Body Force

ah ok, that’s something different. :slight_smile:
thanks.

with the plainforce I get a big wave, but no movement… http://c2n.me/3sUMUGE.png
what’s wrong?

best regards
themaxxer

the plain force is not affecting the liquid behind it, if you need entire container to be affected, you have to place it properly

Say I just want a simple wind effect, where I animate an upward force to ramp up over time. I can no longer use Wind. I can’t seem to get what I am after with PlainForce. When the strength is set to 0 it still applies a strong force.

Suggestions on adding a simple one direction force I can animate?

Thanks.

Well, this sounds like a bug, it shouldn’t do anything if the strength is zeroed. Will check it and get back to you. Are you using it on liquids or fire/smoke?

Yup, found it - will bump the thread when the fix is in the nightlies - hopefully in the next couple of days. Thanks for reporting that!

Edit: Would it still be possible for you to post a screenshot of your setup and the effect it produces to make sure we’re on the same page with the issue?

Glad I am not crazy. Though I wish it worked.

Unfortunately, I removed the PlainForce from the scene because it was not working right…

Also, is that supposed to be “PlaneForce” like a geometric plane? Or “Plain” as in ordinary or vanilla?

don’t forget that the plain force is combined, it has not only acceleration part (force) but a drag part as well. this means, even if the force is zero, the drag may still affect the simulation.

It is “Plain” as simple force - it will push the fluid in the desired direction, just like a regular wind will do.

Basically if you want to disable the plain force with a current build, try setting both the strength And the drag to zero and see if this works as intended. We’ll change this soon in order to behave more intuitively.

Cheers!

Thanks. Would drag be pushing my particles up (in the direction of the arrow)? I figured drag would act only to slow particles down (apply drag).

I need to set up a simple scene to test it out.

Ipwe made the shot work using buoyancy instead in this case, but if I can get PlainForce to work as needed then it would be better.

Perhaps consider calling it SimpleForce? This would avoid any confusion with geometric planes. (Got love English…)

Thanks.

Yup, might be better to change the name, the plain vs plane question arises pretty often :slight_smile:

Please check if you could repro the issue you had - sounds like it might be something else indeed.

Cheers!

Bump - in the latest nightly, the drag will be proportional to the strength and won’t affect the liquid when the strength is zero.

Cheers :slight_smile:

Great. Thanks!