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Everything posted by davpe

  1. it's all pretty good! can you tell something about your technical approach? have you also tried other kind of trees / other plants?
  2. thanks for posting your finds toadstorm, that's certainly helpful! guess it's worth submitting as a bug to sidefx.
  3. Hi, can anybody confirm or invalidate my suspicion that op: expression in shaders context (mat or shop) cuurently doesn't work? I know syntax has been a bit inconsistent between different Houdini versions but right now in 16.5 it doesn't seem to work at all for me. i tried: op: /obj/copnet/OUT op: "/obj/copnet/OUT" "op: /obj/copnet/OUT" op:`opfullpath('/obj/copnet/OUT')` and many other mutations of the same thing. anybody? thanks, D. file attached just for case copReferencing.hiplc
  4. this question has been asked many times already at this forum. see posts below. in general, Mantra is historically aiming at complex fx shots for film productions. given that its strength is more in flexibility and handling huge data sets rather than speed (in H17 thou there should happen major improvements to Mantra). customizability and shading context is where Mantra really shines and allows relative painless rendering of shots that might be very tedious to do with other renderers. if you need to render packshots or product/architecture visualizations there are better suited render engines for sure.
  5. Why is it so

    well those are just two different nodes. initialization of N has been implemented in group expression SOP, so you don't have to do it. apparently, this is not the case of delete SOP.
  6. Bunch of thoughts on SubD modeling in Houdini

    select adjacent - ok this is not possible at 1 click right now. you would have to 1 - select a poly, 2 - make a group, 3 - grow selection, 4 - make a group that equals a boolean difference with the first group. guess that makes you rather not needing adjacent selections extracting geometry in houdini works exactly like that. blast or del or split node. to me, it seems that copying/pasting geometry in any other package works exactly the same way only you don't see nodes. I'm using houdini for modeling quite a bit. I guess with any app you have to adapt to slightly different tool set. Still missing some functionality too, but I found my way around. For modeling some things, Houdini is actually really great. DM plugin looks really nice. Would be interesting to have that implemented out of the box.
  7. Bunch of thoughts on SubD modeling in Houdini

    hi, geo creation - as far as I know, you have to either place your geometry manually or automatically with center in 0,0,0 (with ctrl) target weld is something I wish too select adjacent like grow selection? ctrl + g insert multiple edges with placement control... we don't have that. hopefully in the future releases. pivot - you can switch to pivot mode and move it as a gizmo or snap it. very handy. hotkey is ' mirror & subdiv preview - yep, more work needs to be done here extract - if you want to extract a poly to start a new shape, just select the poly and delete others... if that's what you want. what extract shelf tool does is it takes the selection and extracts it as an entirely new object. merge - you can create a shelf tool with python script that does that. I've done that for most frequently used nodes so I can access those with hotkey.
  8. Help With Speeding Up Render

    yeah that's what i've learned too, that classic shader performs significantly better in this case. ggx is supposed to give more plausible rendering than phong (and it does), unfortunately it also means that insufficient sampling is more apparent. phong is showing no noise but also lacks some detail.
  9. Help With Speeding Up Render

    Useful observations Toby, thanks for the effort! I think this is probably just a thing where Mantra haven't managed to catch up with competition in how efficiently things are implemented. I might be wrong thou... either way its definitely worth reporting as an issue. Your scene makes an excellent example
  10. well I usualy dont look at mentioned image planes, but i suppose it simply indicates how many samples was used for each particular pixel in the image. in the same way thou, you can output each ray channel (by that i mean direct diffuse, indirect diffuse, direct reflect, indirect reflect, etc...) into an image plane and see where noise is present. then you just bump up sampling rate for that kind of rays. in general, min and max ray samples and Noise level helps to reduce general noise in shader evaluation, set of "Qaulity" sliders helps to reduce noise for indirect rays and Pixel samples are improving overal picture quality and reducing noise in motion blur samples. also, note that optimizing renders and reducing noise is not only a matter of typing "good" numbers in mantra node. you can run into renders that are impossible to sample properly if you choose inapropriate lighting strategy or rendering engine. it is quite comprehensive topic so I suggest you making a lot of experiments, ask specific questions and post scene files if possible. cheers, d.
  11. that is what I tried initialy. then I was trying countless possible variations on that until I came to conclusion it probably doesn't work in 16.5. is it working for you guys in hou 16/16.5? that is my general question, whether it is a bug or something wrong on my side.
  12. good point, but no, it still doesn't work
  13. Help With Speeding Up Render

    i'm playing with it right now. with 6x6 pixel and 1-12 rays at 0.007 noise level and filtering on gaussian refilter it already looks pretty clean. hard to say how that will do in animation. ray histogram tends to be much smoother but also washes away some detail and is more prone to artifacting. let us know your results if you get some
  14. Help With Speeding Up Render

    btw speaking about filtering methods, sidefx actually made some attempts to implement this in Mantra too. honestly, I haven't had a very good experience with it so far but the truth is I haven't really explored it too much in depth. so if you take a look at Pixel filter on Mantra ROP you'll find some interesting ones like Gaussian with noisy samples refiltering or Ray histogram function. images bellow were all rendered under 1 minute with 1 ray sample fixed with mentioned filtering methods. looks great but for instance Ray histogram function introduces some nasty artifacts in highlights and I'm not sure if you can tweak it enough to get production quality animation out of it. not sure about gaussian refiltering as I was not even aware it's there (so I suppose it must be fairly new). anyway it seems to do a decent job and might be worth trying.
  15. Help With Speeding Up Render

    well, i agree my conclusions might sound a little bit exaggerated don't get me wrong, Mantra has been my renderer of choice for a few years now and for me as a user it is certainly good and pappreciated that sidefx is making efforts to improve it. Now I'm no expert in programing render engines but it looks like the basic math how to compute lighting is more-less the same for all the pathtracers. So I assume the biggest impact on how fast a final image can be computed has either importance sampling (and this is where Mantra is certainly not that great) or various filtering methods that can take a few scattered samples and make it look good enough (so we're introducing some degree of bias again). I know Renderman's denoise filter does a pretty good job and for gpu engines I think this is bread and butter. Anyway i guess this may be a way to go in general to get noise-free images more quickly. An of course, gpu speeds up all of it due to its architecture that is built specifically to tackle rendering tasks, unline general purpose cpu (that's why I think cpu rendering will die out eventually). As for GPU option in Mantra, that would be certainly great... we'll see a few interesting videos on image filtering methods and importance sampling if anybody's interested:
  16. Help With Speeding Up Render

    yeah, as you said, Mantra is the best for many other things. But with Mantra not being the only product nor the most important one for sidefx, it must be hard to catch up with competition on everything. especially with gpu renderers stepping up, it must be a difficult dilemma whether to even invest time into further improving Mantra, which is, by design, something that seems to be on it's way to extinction in a few years as common cpu renderers have really nowhere to go much further (in my opinion). Many people are nagging that gpu renderers can't do everything cpu ones can, but looking at redshift, I think this argument is quickly loosing its ground. Reminds mi when old scanline renderers were gradualy replaced by GI. It took some time but at certain point, when GI solutions matured enough and hardware became fast enough, there was really no point for going back to scanline again (for 99% of users). Looks like it's almost time for sidefx to start developing a new gpu based renderer
  17. Help With Speeding Up Render

    hmm, this sucks .-/ but i mean, even if this is probably a poor performance compared to average competition, I've run into impossible render scenarios with any tool I have ever used. it's good to have an access to yet different rendering tool as well so that can ballance for shortcomings of the first tool. good news is almost any competitive renderer out here is great for doing such a nice scientific packshot or what the hell it is
  18. Help With Speeding Up Render

    or, have you tried biased gi-render? think it's worth trying. I have changed my mind about this recommendation
  19. Help With Speeding Up Render

    this is my take on Mantra render. try to open attached file and render mantra2 ROP. seems like classic shader does a bit better job with ray sampling (at least in this case) so I used that one instead of principled, with exception of the glass dish which looked considerably better with principled (pretty sure you can achieve equally good look with classic but i was lazy ). it should render apparently faster now but still not great, to be honest. no image is attached as I never finished the frame for time reasons I only tested stuff on interesting regions of the image. seems like gpu renderers are truly beginning to take over... just for overview - at the end I somehow ended up with 6x6 pixel samples as opposed to your 12x12 and 1-24 ray samples as opposed to your 1-40, and turning off sss for liquid as that had minimal visual impact. lights in your scene were seriously oversampled with no gain to image quality. so i set them all back to 1. Also, there was an interpenetration of liquid and glass - some noise/slowness may be caused by that, but that's hard to say as I haven't run too many test renders due to "speed" hdr for enviro light is different in my scene as you haven't embedded original one but that shouldn't make any noticeable difference in speed. oh, and when fighting nasty speculars on edges you'll do much better if you allow rendertime subdivision (Render polygons as subdivision = on) cheers, D. Test_Render2.hiplc
  20. override all materials by simple depth shader (style sheet or take), put matte object into force matte and render as a separate pass
  21. Just another laptop question

    yeah, I was comparing to Precision 7520. that's completely different body and significantly higher price. difference being better cooling, two hard disks, supposedly better quality control and slightly better performance (have done some research
  22. Just another laptop question

    pusat: I am thinking recently about buying some laptop out of a Dell Precision series. they look great but are much pricier and heavier than XPS ones. so I'm wondering what is the real difference between them? By specifications it looks like performance-wise it should be close. It has different CPU/GPU but don't tell me it makes 1kg and $1000 difference? Also, anybody knows why all manufacturers put only 8 or 16 gb ram into 99% of their mobile workstations? (at least in europe it is the case). who wants a workstation with 8 gb ram? that makes you always open it to install additional memory which makes your warranty go away .-/ that seems like a joke considering many gaming laptops have 32 gb built in.
  23. Just another laptop question

    this new thing looks interesting. I am very discouraged from hp brand thou, due to my recent experience. I did a mistake of buying Zbook G3 online, without actually seeing the real product before. After a few days of using it I was quite disappointed by build quality (considering the fact that my previous hp laptop was top notch). I mean, performance is good enough but for $4000 I expect a product that is also built well and offers a great user experience. Creaky plastic body, mediocre keyboard and cpu fan interfering with speakers doesn't make me go with hp next time. or am I just spoiled and shitty build is usual even for high-end these days?
  24. hi, i've never tried to count samples so I don't have complex answer for you. But there are a few pieces to the puzzle 1 - Sampling itself doesn't affect which rays are fired (as you already found out). it only affects the image quality. if you want to control rays fired you have to go to Limits tab and set ray limits for individual ray types. If you set any type of ray to 0, that means no indirect samples of that type will be fired. 1 = one bounce, 2 = two bounces... you get the idea. 2 - i'm not sure if you ever need to "figure out" how many samples you're firing in Mantra. Unlike Arnold, all sampling controls in Mantra are separated. if you use ray variance antialiasing (which is on by default) you can specify a threshold - min samples and max samples - and a noise level which is basically a sensitivity measure. at each sampling point Mantra decides what number of samples will be fired (by difference in values of neighboring samples). but you know it never will be more than max or less than min number of samples. as for indirect samples it tells you what the max number of samples is. 3 - as for sampling Quality sliders, those are only multipliers for indirect samples. so if your ray variance threshold is 2/16 and Diffuse quality is set to 2 it means that indirect diffuse samples will be sampled by double rate of 4/32 samples. also, you can decouple indirect samples altogether (by adding extra parameter to a Mantra ROP) and sample indirect sampling by its own ray variance antialiasing. that I find extremely convenient as you don't have to oversample primary rays just to get rid of noise in bounced light (very typical with Arnold). 4 - also, you have something called Stochastic transparency which affects pixel sampling of transparent surfaces (very useful for volumes). hope that helps. D.