Jump to content

Tweaking fluids -Need expert's eye


Macha

Recommended Posts

I'm trying to create the effect of diging-out-sand.

I used particlefluids and it works reasonably well but I find it very hard to get the look right. The fluid keeps sagging back and increasing viscosity only goes so far.

I also tried a Volumefluid but the fluid keeps flowing back as well (much more so than the particlefluids).

So, for any fluid experts out there, what settings would you recommend?!

sand_ONE_exp.hipnc

sand_Volume_ONE_exp.hipnc

Link to comment
Share on other sites

Sorry I haven't looked at your scene but I have tried the technique described here and it worked surprisingly well, very fast and stable.

You could make a surface out of a sim like that and use shader noise, should have nice results...

Link to comment
Share on other sites

Sorry I haven't looked at your scene but I have tried the technique described here and it worked surprisingly well, very fast and stable.

You could make a surface out of a sim like that and use shader noise, should have nice results...

That's interesting, thanks for the tip Sam.

I tried it but my sand just collapses listlessly. There are so many settings...do you happen to remember what the crucial parameters are to tweak?

Link to comment
Share on other sites

That's interesting, thanks for the tip Sam.

I tried it but my sand just collapses listlessly. There are so many settings...do you happen to remember what the crucial parameters are to tweak?

Had a play with this tonight, attached a hipnc.

I didn't set very much different to the what is decribed in the link, mostly just the distribution of the particles to tetra, the grain size and set the bounce to 0. I did play around with the settings on the gas solver but didn't get too far... it seems like this would be alright with a heap of particles, but i'm not that patient tonight :)

I think it just needs some kind of viscosity force, but it didn't work by just turning it on in the fluid object ... :/

Also, I took out the xform in the knife SOP network so that it didn't have to be a deforming geometry in the DOP network.

sand_ONE_exp.hipnc

Link to comment
Share on other sites

Hoho, that's interesting! It looks more like sand now, thanks! I will try the viscosity settings.

Also, I took out the xform in the knife SOP network so that it didn't have to be a deforming geometry in the DOP network.

I didn't know you can do that (how?). It makes the sim quicker?

By the way, sometimes if I tweak scenes where I enable this more rigid behavior I get particles that fly off at incredible speeds as soon as they touch anything. I don't know why that is.

Edited by Macha
Link to comment
Share on other sites

Hoho, that's interesting! It looks more like sand now, thanks! I will try the viscosity settings.

I didn't know you can do that (how?). It makes the sim quicker?

By the way, sometimes if I tweak scenes where I enable this more rigid behavior I get particles that fly off at incredible speeds as soon as they touch anything. I don't know why that is.

If you have "deforming geometry" checked then the static object / rbd object will create an SDF on every frame, which gets very slow if you have complex geo and/or a lot of divisions in the SDF. By moving the transform stuff onto the geo node, and checking "use transform" ( something like that) on your dop object, then the sdf will just be created on the creation frame and then tranformed around using the transform on the geometry.

hmm, in this particular case I would expect the particles to do unstable things since the knife is completely immovable ... no matter how much they push back on the knife the particles have to go ... somewhere else...

Link to comment
Share on other sites

Here's where I get stuck. The grains just start flying off and I don't know what to do about it. If I enable viscosity in the fluid slover then I get an error of a "missing viscosity attribute". I can't seem to get rid of the craziness in there! Especially when reducing particle separation in the ParticleFluidObject DOP.

Sand_Scoop_Grains_Test_Ab.hipnc

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...