itriix Posted August 24, 2009 Share Posted August 24, 2009 (edited) hi everyone, so i've been reading every post i can find, watch every tutorial online about the houdini fluids, (pyrofx especially), and have a few questions. one: say i just want to have a flaming sphere fall and hit the ground... so i click a default sphere, make the voxel grid size the WHOLE size of the "possible fluid sim" scene area... and then run the sim. And so, it just has me a little confused on "efficiency" and "tricks" to save time. At the default size of the scene, with a default sphere, *not scaled or anything* the voxel grid size needs to be about 15 x 25 x 15... and that's with 50 divisions. *which seems maybe too low for that size?* and then upres it, which would be 150... but the thing is, is it better to maybe just scale the sphere down, zoom in with the camera, use a "smaller" voxel grid size, and change the paremeters in order to make it still seem the same "weight and size" as the original sized sphere? so that's the kind of things i'm thinking about. scene scale, sizes of the sphere, sizes of the voxel grid, and divisions... especially in the "low res" sim. so then next though is the up res sim... however, i think that i need to get the lo res looking good first. The next thing i'm curious about is, what is the easiest way to be "testing parameters" in the upres? something seems wrong with the process i'm using. example: make my low res sim, and then run upres... say i want to tweak params on frame 80 because it has a good amount of smoke and fire, but if i tweak params of the upres at that frame, it will have to recalc all the way back to frame 80... however, there is no information on frame 1, so i can't just tweak values on frame 1 and see results. so what's the best method for tweaking upres parameters? especially for learning exp so hopefully the request for the "hip files to the h10 promos" will come true. that would be so much easier for learning from the beginning. these tutorials are great! BUT, they seem to be level 2 instead of say level 1 in experience... Thanks for all the help, and if someone has an interesting, good looking explosion hip file they could share that would be AWESOME! I'd like to see what settings people are using, and sizes of voxel grids, and etc... you get the point thank you all a lot Jonathan oh and here is a vid 150 voxel low res, 250 upres... took FOREVER... but every time i was working at 50 res low res, and 150 upres, i wasn't getting that "INTERESTING" detail and when i try to get that fine detail in the shader, i still am not getting it. obviously i'm doing something wrong. so this was my final attempt at getting some decent detail. but since it took so long for "simming the low", simming the hi, and generating the point clouds, and then finally rendering... once again though, seems like i should be able to get better results at lower res... something is missing here pyrotest9.mov Edited August 24, 2009 by itriix Quote Link to comment Share on other sites More sharing options...
wolf_cub_one Posted August 25, 2009 Share Posted August 25, 2009 oh and here is a vid 150 voxel low res, 250 upres... took FOREVER... but every time i was working at 50 res low res, and 150 upres, i wasn't getting that "INTERESTING" detail and when i try to get that fine detail in the shader, i still am not getting it. obviously i'm doing something wrong. so this was my final attempt at getting some decent detail. but since it took so long for "simming the low", simming the hi, and generating the point clouds, and then finally rendering... once again though, seems like i should be able to get better results at lower res... something is missing here pyrotest9.mov Hey Jonathan, How slow are your simulation times for both lowres and upres? What are the specs of your computer? Reading your post I decided to just do a simple pyro setup with some minor tweaks. My processor is a Q6600. Not the fastest processor but my lowres 150 sim took about 15 minutes and my upres 250 sim took about 45 minutes for a 90 frames animation. Are your times comparable? Oh I did these sims without adding scattering since this was a simple test with a basic pyro setup. Maybe the scattering is what is causing your increase in sim time. As for your video, you're off to a really good start. Though I do agree that for a 250 upres, there could be more details in the smoke. I looked at your animation at a gamma of 2.2 to be sure. You do have some nice details but your 250 res look more like my 150 lowres. If you can give me more details on what changes you made to the basic pyro setup and if I have the time, I'll see if I can help you further. Good luck Quote Link to comment Share on other sites More sharing options...
itriix Posted August 26, 2009 Author Share Posted August 26, 2009 Hello, thanks for the response. I am currently using the 8-core 2.8 ghz Mac Pro with 10 gb ram. NVIDIA GeForce 8800 GT. OS X Leopard 10.5.8 As for my sim, I didn't tweak ANYTHING except the length width and height dimensions of the low res grid in order to keep the smoke from hitting the edge of the wall and cutting itself... I set the divisions to 150... Changed Advanced Settings Dual Rest to 1 and 60. Upres set to 250 voxel divisions. That was it! I've just recently started playing with dops and so am trying to get a feel for what are the important parameters to be playing with... what values give particular results. and then trying to play with the pyro shader. I'm just not getting anything i'm happy with yet, so i just keep tweaking settings and then doing the whole process over, *resim lo-res, resim hi-res, regen scatter pc, render* I am aware that the scattering takes time to "generate" and then it adds a great deal of time to the "rendering" unless you turn down the max search radius *as an example*.... these weren't the times that i was referring to though as my "sim" times. strictly just the low res sim and up res sim times are all i'm referring to as the "sim".... I remember that the 250 upres sim took 1.5 hours.... I'm not sure what the low res was... Maybe 30 minutes? Will do another test soon and make better study of the time. and post that info for u. In the meantime, if you have any "nicely detailed" generated smoke hips that i could look at, i'd love to dig through it to see what your doing with your parameters Thanks for the response, Jonathan Quote Link to comment Share on other sites More sharing options...
Mario Marengo Posted August 26, 2009 Share Posted August 26, 2009 Hey itriix (and others awaiting demo scenes for the pyro shader) First of all, thanks for your patience. My current production crunch is finally starting to wind down. Starting next week I should have some time to go back to pyro and finish version 2.0, along with all the shader test scenes (about 30 setups torture-testing some aspect of the shader). So yeah, I anticipate that in about two week's time I should have an update (of the shader, not the simulation -- the simulation side of things is someone else's department ) Cheers. Quote Link to comment Share on other sites More sharing options...
jason_slab Posted August 26, 2009 Share Posted August 26, 2009 awesome Mario, can't wait! btw, great work on that knorr salt and pepper commercial jason Quote Link to comment Share on other sites More sharing options...
itriix Posted August 27, 2009 Author Share Posted August 27, 2009 well that sounds fantastic! thanks! i can't wait Quote Link to comment Share on other sites More sharing options...
essencevfx Posted August 27, 2009 Share Posted August 27, 2009 I've gotten some amazing results with "v01" so can't wait to see what you have in store for us next ! Your right, the new alpha is much faster , the solver as well, that's a pretty good upgarde on the simulation side Looking forward to shader your updates next ! Quote Link to comment Share on other sites More sharing options...
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