Following this tutorial for whitewater, however he uses a VOP SOP @ 30:30 into the tutorial (https://www.youtube.com/watch?v=l2u-DXOxouY) [youtube.com] for separating particles that have a change in velocity. What do I need to use as a replacement to do this? Still a beginner here so if someone could break it down a bit I'd really appreciate it. Thanks very much.

Neil

hi

Use a Point VOP, which is actually an Attribute VOP.

J

Worked like a charm! Thanks very much

Neil

I just came back to this after being away for a bit, but I'm again having issues with this tutorial when he comes to creating the spray sim DOPNetwork at 44:10 and having the separated particles created become emitters. I don't get the same results with Houdini 15 as things have obviously changed when creating the POP object and POP solver. Where exactly do I go from here to get things working? At a loss…

Again, appreciate any and all help.

Anyone? Maybe a link to a different particle tutorial that would cover this?

Yeah, you simply use the Whitewater shelf tool in the Particle fluids tab.

Ah, thank you. Didn't even know there was one there.

OK after adding the white water I lost my fluid mesh and it has been replaced with spheres. Can't figure out now how to get the mesh back. My particle_fluid object node still displays the mesh in my viewport, yet renders spheres… Nothing has changed inside the particle_fluid object.

Doesn't happen to me. Can you simplify your scene and post it ?

Here is the file. I reloaded a previous save and tried reapplying the whitewater, and I now receive a “No fluid object selected for whitewater” error. So I can not get the whitewater to work at all now in the scene when I try to apply it to my flipfluidobject in the DOP network.

Also, at some point the FPS in my scene started to drop heavily. I had figured it was due to my older machine and the geometry starting to really add up. However, after deleting nearly everything from the scene to give a simple file, my frames are still drastically low, which it wasn't like at all before the scene started getting more complex. Not sure what is going on but it is this way for me in the file I'm uploading when they used to be butter smooth.

Another issue is the geometry on my main cliff object needs some serious cleaning up after the poly extrusion. Might just have to start another thread on how to go about doing that though… I'm not sure if most are expected to have a lot of previous modelling experience before jumping into Houdini, but mine is quite limited so I'm still learning modelling techniques along with learning Houdini at the same time. Anywho… really appreciate the help A-OC.

I couldn't check your file properly because you forgot to lock the file sop inside the cliff geometry.

But you had the Flip Object hidden flag on, that might have been a problem.

I added the white water and everything works as expected.

I do it like this: Select the Flip Object and Flip Solver nodes, then click the shelf button.

Alright, got the whitewater to work again however, my fluid sim has reverted to spheres again. Here's an updated file with the Geometry file node locked. Also, is this whitewater more of a fog then rather small geometric particles? Seems to have an odd look to it. Cant find anything on the web regarding working with the whitewater shelf tool and all of it's features.

http://www.filedropper.com/whitewaterbasicscene2 [filedropper.com]

Hmm, I don't know, still doesnt seem to look right. Or is this this how it should look and things will look proper when fully animated? Any advice for further tweaking? Seems a bit too “streaky.”


OK, Making a bit of progress. The big spray at the waterfall looks a bit goofy, but at least I'm getting somewhere now. Thanks again A-OC, I owe ya one!

OK after playing around with it this seems to be the best result I am able to get, which is somewhat unsatisfactory. How do I get the results from this image which was done in Houdini? https://i.vimeocdn.com/video/496148453.jpg?mw=1920&mh=1080&q=70 [i.vimeocdn.com] The foam looks much better having spectacularity and actually floats on the surface of the fluid itself.

((Ignore the texture on the base of the model below which hasn't been UV mapped yet.))

The way I do it is very slow when rendering but it gives me the most satisfactory results as of now.

Render as small points, around 1 mm in radius, with a water-like reflection, no refraction, opacity around 0.15, faux caustics. Maybe add a little diffuse.

I'd be very glad to hear a faster approach.

*edit. Actually add a lot of diffuse, now that I'm checking.

It gets faster as I dial up the opacity but it also starts looking like sand.

OK so do you change the shader then? Its set up as a smoke shader with no reflection, refraction etc. options available. So it should turn to particles if I do that then? Hmm… I'll give it a whirl anyway. Didn't think to try changing the shader from smoke…

Yes, instead of generating volumes with the Volume Rasterize Particles, render as plain points. Also assign a default mantra surface and work from there.

Here's something I'm working on as we speak

Ah very nice. That is exactly what I'm after. So then I am replacing the Volume Rasterize Particles with a Point node? If so I'm not finding any option to change the particle size and they are quite huge when i go to render..