Lagoa No Slip and Static Friction not working - help!

[frosty3907]

Edit: below fix does not work, slightly alleviates issue only.

No slip, static friction has No effect.


Hi there, I was having trouble getting any lagoa material to use no-slip or static friction values on an animated collision mesh as described here:
https://www.si-community.com/forum/v ... =15&t=3711

I have discovered that the problem comes from Substeps being >1 in Time Step within the Lagoa Simulate Multiphysics.

So this means you will probably need to use Playback Options to change your framerate to something like 120fps.


Note that just changing the framerate is not enough, you need to have Substeps = 1.

A workaround but there it is.

[origin]

time step never worked for me, at least for moving objects. I also went for high fps, up to 2000. There is also native icetree substep property since 2013 or 2012, might be worth checking out.

[Bullit]

Framesteps couldn't help this?

[gustavoeb]

I also resort to this workaround you described. Have filed this animated collision bug before, and encourage others to bump this with support guys.
Just to clarify it does not matter if you use the substeps in lagoa sim node or the pointcloud propertie, collision will only be calculated using passive objects last fullframe position.

[frosty3907]

Actually this doesn't seem to have fixed it at all.

[frosty3907]

can someone confirm for me please that static friction/no slip have no effect?

[frosty3907]

I don't think internal friction even works, have you tried making a pile of grains?

I have one day left to do this job and I'm at the same place I was when I started a month ago.. No friction.

[gustavoeb]

Static friction and no-slip work.

Do you have the correct properties set on your collision object? If not, do this:
1. Select the object
2. Under the ICE module (default keymapping: 4) Particles > Collision > Lagoa Particles > Set Collision Data

This will create a new ICEtree in your collision object that holds properties of how particles should interact with it.

Besides that make sure you have all properties you want to simulate checked under the Lagoa Simulation node. Beware that many things can affect the final result of your sim, so it is a good idea to test things one by one in simpler scenarios to get a hang of things.

[frosty3907]

Static friction and no-slip work.

Do you have the correct properties set on your collision object? If not, do this:
1. Select the object
2. Under the ICE module (default keymapping: 4) Particles > Collision > Lagoa Particles > Set Collision Data

This will create a new ICEtree in your collision object that holds properties of how particles should interact with it.

Besides that make sure you have all properties you want to simulate checked under the Lagoa Simulation node. Beware that many things can affect the final result of your sim, so it is a good idea to test things one by one in simpler scenarios to get a hang of things.

Yes I've done that.
It definitely does not work here, did you test it?

Try and have a collision object pass under a lagoa emitter and have the particles not slide right off it.

[gustavoeb]

Not in front of SI. Does your material have inelastics on?

edit: correction should work even with inelastics off in your material

[gustavoeb]

Here is a comparisson. Noslip is suttle since it is most relevant at the moment of collision. At 6 some particles will slide to the sides making room for other particles, at 0 they tend to stay inplace until pushed aside. Difference to sim without static and no slip is very clear.

[frosty3907]

Those look identical!