Jump to content


  • Content count

  • Donations

    0.00 CAD 
  • Joined

  • Last visited

  • Days Won


davpe last won the day on September 22 2017

davpe had the most liked content!

Community Reputation

60 Excellent

About davpe

  • Rank

Personal Information

  • Name
  • Location

Recent Profile Visitors

2,190 profile views
  1. thanks for posting your finds toadstorm, that's certainly helpful! guess it's worth submitting as a bug to sidefx.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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
  8. 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.
  9. 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.
  10. good point, but no, it still doesn't work
  11. 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
  12. 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
  13. 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.
  14. 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:
  15. 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