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Showing most liked content on 12/21/2018 in all areas

  1. 1 point
    Here is a fix, also have a look at this Also look at Toad blog if you want a short version https://www.toadstorm.com/blog/?p=493 testc_2.hip
  2. 1 point
    Yes, glue constraint parameter Propagation Iteration appeared since H17.0 thus to get the same result in H16.5 you should set detail attribute i@propagate_iteration in SOP and i increase value of @strength some more in wrangle from 1000 000 to 1 500 000. reduceStrength_002_fix_h16.5.hipnc
  3. 1 point
    OK, here the file reduceStrength_002_fix.hipnc
  4. 1 point
    + "It doesn't freeze Houdini and you don't have to close your editor to see the updated code applied on your parameter." http://cgtoolbox.com/houdini-expression-editor/
  5. 1 point
    oh sorry, i forgot to attach that hipfile. will do once i get back to my desk. i just rewired your setup a bit and it really isn't any slower.
  6. 1 point
    here. your scene rendered in 6 minutes on my laptop, with close to zero startup time, and consumed 700 mb of ram. what I did - first of all, the reason for your high startup times and crazy memory demands were actually nested packed primitives. nesting itself would't be an issue if you weren't nested thousands of packed prims... that actually makes packed geometry more expensive than rendering just plain meshes. just have one packed prim per tree - or maybe two if you want to separate leaves and wood. so if you unpack completely your tree and pack it again as one primitive, you should see much better performance. another thing is your render settings were completely overkill in some points - like ray limits. with trees or very detailed geometry i find having pixel samples quite high as needed so 8x8 is fine, but setting ray limits to zero made almost no visual difference (in this particular render) and renders faster. you don't necessarily want to have zeroes in ray limits at the end of the day, but point is to cut it as low as you can (and what you've had set there was definitely overkill for this king of rendering). also, rendering a depth of field is something I have never seen done on any project in any vfx house. very expensive to render, and if you don't get it right you have to render the whole thing again. maybe in some very special case renders it makes sense, but generally you do that in comp. regarding instancing in general, i don't think instance object is any faster than copy SOP in it's essence, as a few people mentioned here. it's just that copy SOP gives you more freedom to do stuff and that naturally leads to longer cook times. instance object simply forces you to obey the most efficient workflow. copy SOP in loop is actually the most efficient workflow if you need more than just a bunch of static objects distributed over the points. but if you do a very simple instancing like you do in your scene it actually doesn't make sense to use loops as you're not using any of it's benefits. (but still I haven't found it slow to cook, it was like maybe a half of a second??)
  7. 1 point
    it's true that for mantra, there aren't really any recent detailed tutorials to watch (which is a shame). essentially thou, Mantra is the same thing as any other pathtracer. so if you already know how to use Arnold or Renderman you can translate a lof of this knowledge to Mantra. i have switched to mantra from using mental ray and arnold (like 5 yrs ago or so) and it didn't take me long to understand all the essentials. sure you've got some different names and options to turn on or off, sampling is split into a bit different controls etc. but I mean still you have your pixels and ray samples, ray limits, bucket sizes and so forth so it shouldn't be that big of a deal. reading houdini documentation helps a heaps. mastering Mantra is something that takes a long time thou, for the following reasons: mantra has TONS of controls you can use to optimize (or de-optimize) the rendering process. That's sort of good and bad thing at the same time, depends on what you want and how good understanding of these settings you have. I like having a lot of control so I love Mantra for giving me million sliders and toggles that many users never touch. You can do stuff with it that can save your ass sometimes - because you can for instance render out some odd render pass that helps compositing tremendously and saves you from running an expensive render. Or sometimes you realize that if you use this in combination with that, you can very easily render an effect that would be otherwise painful or time consuming to do. Unfortunately, "uneducated tinkering" can equally well turn your "grey sphere on a checkerboard" into rendering nightmare that takes 90 hours to complete - your call Some people are driven crazy with that bcs they just want to set the slider to "good quality", hit the render button and get that picture done (can't blame them). One objectively BAD thing in Mantra, especially for new users, is that among it's numerous parameters (half of which is actually "hidden", and you have to go to Edit rendering parameters interface to access it) there are a few inconspicuous ones that can make a big difference in how long and in what quality your picture actually renders (in some cases), and there is no way to know unless you're told, or you spend time figuring out why this particular scene eats up 100GB of ram if there is apparently no reason for that. Then you discover this hidden parameter having completely inappropriate default value (which turns out to be an issue if you render more than certain amount of texture data in your scene for example). i personally think stuff like this is one of the main reasons that makes many users turn to some easier-to-grasp solutions like Arnold, that is quite limited in what you can do with it, on the other hand thou, it's very easy to use, and you don't have to be an expert user to get quite consistent and predictable results. So my advice on learning mantra is, learn how raytracers are working in general, then read the docs and then do a lot of experiments with things you're not sure about. Having said that, in this article you can read about some of those nasty hidden parameters: https://vfxbrain.wordpress.com/2016/03/16/mantra-tips/ And maybe some more tips here: https://vfxbrain.wordpress.com/category/rendering/ cheers.
  8. 1 point
    You can set up an inward cylindrical projection (based screen coordinates ranging from -1 to 1) like this: vector pos = v@P * M_PI; float r = chf('radius'); float h = chf('height'); v@P.x = sin(pos.x) * r; v@P.z = cos(pos.x) * r; v@P.y *= h; v@N = normalize( v@P * {-1, 0, -1} ); Inside a lens shader v@P would be called P and v@N would be I. Unfortunately SideFX recently changed the way to create CVEX operators. Does anyone know how to use CVEX in Houdini 17? Also make sure to check out Paul Ambrosiussen´s tutorial (for H16.5): https://www.sidefx.com/tutorials/lens-shaders-for-gamedev/ inverse_panorama.hiplc