hi.
how can i fix it ?
evey thing is normal the simulation is pretty fast but right after frame 100 it goes slow motion. its like there is no more gravity or velocity.

i am using houdini 12.1

If you have buoyancy enabled the combination of upwards velocity and diffusion/cooling of temperature will cause the fluid to kind of float where the temperature has been reduced to where gravity is stronger than buoyancy. Try reducing the rate of cooling and temperature diffusion

nope that didn't help

i am really wondering! why is it this way?

Hmm! and something else that i didn't noticed it before, it only happens with “volcano”.

An example scene containing the problem would make it much easier for others to help you debug this problem.

At a guess, check that your “Timescale” parameter in your pyrosolver node's simulation tab is not being animated, likewise the “Scale Time” parameter on the AutoDopNetwork node itself.

oh my god!, that was too good for a guess.
it was Timescale in pyro solver.

each time i am creating a volcano this expression “ease()” is the default value for that Attribute. i just deleted that expression and every thing works great now.

Thanks a lot.

m-motion
oh my god!, that was too good for a guess.
it was Timescale in pyro solver.

each time i am creating a volcano this expression “ease()” is the default value for that Attribute. i just deleted that expression and every thing works great now.

Thanks a lot.

Just to shed a little extra light on this, from what I understand the reason that the Timescale attribute is animated in the volcano preset is to reduce the amount of runup time that it takes for the fluid to reach its full shape. It's meant to be a fairly slow boiling effect, and if the whole sim was that slow it would take a while just for the runup portion.