Morbid Posted March 9, 2011 Share Posted March 9, 2011 Hello everyone, I'm working on my graduation project which includes a few shots with a large scale ocean. At the moment I'm getting familiar with HOT, creating foam particles, etc. I'm doing this on small grids to test, but it already takes a lot of time to cook. I'm afraid how this is going to be on a large scale ocean which I need at the end. With large scale I mean that you can see the horizon. Can someone give any advice on how to approach this? I don't have access to a render farm so it has to be done on one pc. I'm using the non-commercial version. Cheers, Maykel Quote Link to comment Share on other sites More sharing options...
Sean Lewkiw Posted March 23, 2011 Share Posted March 23, 2011 The last time I had to do an ocean, I tried the HOT, but could not get rid of the tiling. So I took the VEX Choppy Water Shader and recreated it in VOPs. Then I did large-scale deformations of the ocean surface as geo defs using the same code with some sharpening of the wave edges, plus added some more layered noises. I extracted height from a top-down render which I then projected back on to birth white caps and spray. Wake was created by attribute transfer of the boat on the geo and then using noise in the shader. It was very painful but it looked pretty good in the end. Quote Link to comment Share on other sites More sharing options...
David Cordeiro Posted March 24, 2011 Share Posted March 24, 2011 (edited) Could you separate the foreground from the background ? Like doing a hires sim for the foreground and blend-it in post with a lowres background or even a mate-painting or footage ? It really depends on the shot,usually you don't need much detail at the horizon line, especially if the day is hazy. Edited March 24, 2011 by David Cordeiro Quote Link to comment Share on other sites More sharing options...
Marc Posted March 25, 2011 Share Posted March 25, 2011 To get rid of the tiling I've layered multiple HOT vex nodes at different angles (ie rotated layer2 45 degrees). Most of this was done in a displacement shader so render times were manageable. It got rid of the tiling for the most part, but needed some tweaking on a shot by shot basis to get rid of patterns. You can also try and cull your ocean plane outside of the camera frustum. That plus a lod setup where the grid gets more subdivided closer to camera works wonders. Cheers Marc Quote Link to comment Share on other sites More sharing options...
Jason Posted March 25, 2011 Share Posted March 25, 2011 If you're rendering with Micropolygon or Micropolygon-based PBR, be sure to look up the Z-Importance dicing settings. This can improve performance for horizons: Houdini Docs: Advanced Dicing Quote Link to comment Share on other sites More sharing options...
Marc Posted March 25, 2011 Share Posted March 25, 2011 Cool setting... how much does that screw with RAM usage though. I imagine it can get messy if you're not careful. M Quote Link to comment Share on other sites More sharing options...
Morbid Posted March 30, 2011 Author Share Posted March 30, 2011 To get rid of the tiling I've layered multiple HOT vex nodes at different angles (ie rotated layer2 45 degrees). Most of this was done in a displacement shader so render times were manageable. It got rid of the tiling for the most part, but needed some tweaking on a shot by shot basis to get rid of patterns. You can also try and cull your ocean plane outside of the camera frustum. That plus a lod setup where the grid gets more subdivided closer to camera works wonders. Cheers Marc Ok but how would I get accurate foam emission if I use displacement shaders? Is it possible to get the height and curvature information out of a deformation shader to use in a pop network? Quote Link to comment Share on other sites More sharing options...
ikarus Posted March 30, 2011 Share Posted March 30, 2011 i would do a lower resolution displacement in sops, then do more displacement in your shader, that way you can get those crest isolations Quote Link to comment Share on other sites More sharing options...
Sean Lewkiw Posted March 31, 2011 Share Posted March 31, 2011 Ok but how would I get accurate foam emission if I use displacement shaders? Is it possible to get the height and curvature information out of a deformation shader to use in a pop network? Yeah, this is tricky. What I ended up doing was mapping the displacement map back onto very dense geo, deleting all but the displaced peaks, and then birthing off of this. This way you get velocity as well curvature info. However, it's slow and painful, so I broke it up into lots of grids and ran it on our farm. Now, if you have a boat too, you can get really nice bow splashes by booleaning this geo and birthing points. Quote Link to comment Share on other sites More sharing options...
Marc Posted April 1, 2011 Share Posted April 1, 2011 For the show we were on we fudged it all with shader stuff (hooray for night shots!). But we did experiment with using an orthographic camera from the top of the ocean and generatic a point cloud based off of the eigenvalues and all that good stuff. Then using that pc file as a source for particles which were then run through the same settings in another hot setup so the foam would stick to the ocean surface. Admittedly we never got past the proof of concept, but there's no reason why it can't work. M Quote Link to comment Share on other sites More sharing options...
ykcosmo Posted April 14, 2011 Share Posted April 14, 2011 Marc, sounds advanced professional technology........ |o| Quote Link to comment Share on other sites More sharing options...
gyepes Posted April 14, 2011 Share Posted April 14, 2011 I'm fairly sure HOT comes with an example that shows how you can generate a set of attributes in SOPs in order to birth particles near the cusps. And like Marc suggested layering a set of VEX nodes is definitely the way to go in order to get rid of tiling artifacts. We didn't change their angle much, but we layered a set of Lo, Med and Hi frequency waves and made sure their resulting areas were not multiples of one another. You just have to make sure to get the speed right to not mess up the apparent scale -- this is where previewing as much in SOPs (vs displacement) comes in handy. hope this helps! Quote Link to comment Share on other sites More sharing options...
Whatsinaname Posted September 2, 2013 Share Posted September 2, 2013 The idea with VEX nodes is interesting, but does anybody have a suggestion on how I can adopt this technique using the integrated Ocean Tools in Houdini 12.5? Quote Link to comment Share on other sites More sharing options...
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