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pfistar

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pfistar last won the day on March 17

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About pfistar

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    Nik Pfistar
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  1. hi Ryew of Urth I'll certainly check this out and get back to you, as it looks like it might be just what I need. Thanks for the quick response and cheers, NpF
  2. Hello all, I’m a relative noob and while this seems like it would be do-able, I have no idea which nodes I would need to invoke. I would like to map a repeating (but not tiled) texture on an object that already has an underlying material / texture. (So for example, knots on a tree trunk, or pimples on a human face.) The way I imagine this might work is that once I’ve used Scatter SOP to scatter some points on my base object, I would somehow translate those point coordinates to UV coordinates (Not sure how to do this). Those UV point coordinates could then be used along with a texture’s 2D matrix to map its pixel data per point (Don’t know how to do this). I would also imagine I could use a pscale value with some randomization to vary the sizing of this repeated texture (again, not sure at all how to approach this). I'd also imagine I'd want to use some kind of multi-layered shader with alphas in order to preserve the base layer material properties. I should note that I’m using Redshift here, as I imagine this might make a difference as it might have a few more limitations compared to native Houdini texture/materials workflows (though maybe not?). Preemptive thanks to any responders! NpF
  3. Trouble with Creep and Ray SOPs

    Hi Martin Many thanks for the reply and for the investigation! Before I saw your response I did manage to get things working using the Ray SOP to create my creep surface. File is attached. What I ultimately ended up doing was using PathDeform SOP along with PolyFrame SOP to create my initial tube geo and to keep the normals of the tube I was trying to wrap from straying off their initial horizontal direction. The results weren't absolutely perfect, but were good enough to move forward. I took a look at your solution which is far more Zen than mine - though I don't imagine I would have ever arrived there for a couple reasons: 1) My VEX knowledge is nil, save for the most very, very basic things 2) Allowing the vines to criss-cross as they climb the tree-trunk is essential to the look I was trying to achieve, which is why I chose to copy this tutorial over others of a similar nature. I struggled with re-creating the CHOPs networks to get that point-position randomization, but ultimately it gave me the exact effect I wanted. I would bet there are other ways to do this (for example, I haven't investigated how I might pipe the CHOPs data into your VEX-based point set-up), but this one seemed logical to me, and easy enough to control, should I want to art-direct the randomization. Otherwise, yes Carve SOP is totally a friend! Many thanks again for taking a look and for the general advice! Cheers Nik ray_and_creep_forum_npf_followup_4.1.zip
  4. Hi Librarian Thank you for the response. I'm not sure how you changed the file, but I rebuilt again in HoudiniIndie and the process revealed my errors. Per the CHOP net: - it appears I'd had a syntax error in expression in my Constant node. - also, in looking at the graph view, I noticed the cy value was flat rather than ramped (because I didn't think to put a keyframe at the end ) For the ForEach blocks, it appears I was Fetch(ing) Input, (rather than Fetch(ing) Points,) and was also looking for the eval numbers before evaluation had actually happened (didn't realize you sometimes have to manually force it to evaluate). In any event, thanks again for responding and for displaying your inspiring Houdini work. NpF
  5. Greetings all! I'm a relative noob to Houdini and trying to replicate a CHOP network that was created a few years ago for a Lynda.com tutorial. I triple-checked and with the exception of frame-ranges, all my nodes and settings are identical to the original, though the one critical difference (presumably) seems to be that in some of the old network's nodes, the Mode is set to "Constant Range" instead of "Range" (node info comparison here). I can't find the place to change this setting - hoping some CHOP ninja can help! Here's ink to a reduced version of the original tutorial file: https://www.dropbox.com/s/zlj9uujmpkap46v/LyndaTutorial_Reduced.zip?dl=0 More importantly, below is a link to a file that contains the original CHOP network (copy/pasted from original file) next to my 'built from scratch' new CHOP network: https://www.dropbox.com/s/4k4rd01j1ja97a8/ForEach_old_vs_new.zip?dl=0 I rebuilt the network because the original was a .hipnc. In above-linked file, I've wired up some side-by-side node networks to show how the CHOP net should be working (works fine with the original) and how it's not working (with my rebuild). Attached is a jpg preview of what the network looks like - I'm ultimately trying to use the CHOP to drive an array of points up a surface. Preemptive thanks to any responders! NpF
  6. Trouble with Creep and Ray SOPs

    Hi all, Somewhat of a noob here trying to make vines creeping up a tree trunk (image A). I've put together a series of screengrabs along with my .hip file. Project geo peripheral might be a bit too large for attachment so here's a dropbox link: https://www.dropbox.com/sh/87f6okcs4h6a1xa/AAAXy7BdIlo1eJxFCmvkFzkPa?dl=0 I followed Scott Pagano's tutorial on Lynda, where he sets up the 2d point travel as a CHOP and feeds that into an (old school) ForEach net which holds the Creep node and iterates on a series of points. In Scott's setup, the geo surface the vines travel along is created by conforming a simple Tube SOP around an abstract base geo using the Ray SOP. Using this tutorial as my guide, I tried to do the same by using Ray SOP to wrap Tube around my tree trunk model. Because the trunk leans in a certain direction and has some irregularities in its form, the Ray SOP was having trouble finding what it needs to find to get a good, full wrap all the way up the trunk (image B). So, I tried a workaround, where I took the spine line of the tree, Resampled the points, used Copy SOP to clone series of Circles, and then created a surface with PolyLoft SOP. I figured this would line up the normals a little bit better between wrapping geo and tree geo and give the Ray SOP a better chance of finding the surface. Lo and behold this works quite a bit better (image C) however, now the Creep SOP yields an error saying that the geo surface I'm inputting is "not a surface". What's particularly frustrating is that I had it working for a moment yesterday (was able to generate "creeping" points up the tree surface) but can't recall how my setup was any different from now. What's happening now is that the Creep SOP is placing its points on only a single primitive in my mesh (prim# = 0). (image E) I ran a quick test with other primitive geometry objects: a Box, Sphere with top and bottom truncated using a Delete SOP. This was also yielding the "Input is Not A Surface" error in the Creep SOP, and the points were once again bound to the perimeter of primitive 0. It seems the only geo object allowing Creep SOP to let points travel is geo derived from a Tube SOP (image D). I was wondering if the points' travel ability had anything to do with normal angle, so I cranked down the number of sides to its minimum (3) but the points could still creep and travel around those sharp corners, so I'm wondering if it has to do with how the points are ordered on the surface geometry. Or is it something else entirely - ultimately wondering what separates a recognized 'surface' from a 'non-surface'. I'd also ask if anyone knows of a better way than Ray SOP to conform a Tube to my tree trunk surface. Ideally, the Y value of each point would stay in place, so the mesh would be made up of evenly spaced horizontal loops, though of course X an Z would move to conform to the target surface. Preemptive thanks to any responders! NpF houdini creep and ray.zip
  7. Greetings all, I’m a relative noob in Houdini and am having a hard time trying to create a displaced noise on the mesh of a Houdini Labs Tree Trunk object. Though the Tree Trunk node is open for exploration, I don’t know enough to understand why the following is happening: I try to displace points on the trunk’s surface with procedural noise in an Attribute VOP, using a typical setup (Adding the N value to the P value), but the result appears to not push things outward, 1 to 1. (It looks like maybe things are being pushed according to a tiled UV? I can’t quite tell). I also tried using the Displace Along Normal VOP node, but can’t seem to get that working either. On the other hand, when I use an Attribute Noise SOP, I get the effect I am looking for! What is the big difference here? It appears that the noise here is working on the incoming P value, though when I change it to N, I get nothing. There are another 2 components to this I’d like to solve: With the Attribute Noise SOP, the noise displaces the entire mesh off of its center. This appears to be true no matter which range value preset I use, including ‘Zero Centered’. I would attribute this to the notion that only the points’ position values are being displaced according to the noise, and they’re not being added to their normal values for that center-outward displacement. Is there a way to do this using this node? Perhaps with an expression in one of the fields? As mentioned above, I tried to use a VOP for this, but was unable to achieve what I wanted - (I suppose that ideally someone can show me how to achieve what I need using the Attribute VOP in the first place). The other thing I’d like to achieve is some falloff, where parts of the tree mesh are or are not affected by the noise SOP. The only way I vaguely know of to do this is with an Attribute Transfer SOP and a color value run over P value, however, I hit the wall of shame when trying to figure out how to use those color values to drive the noise that drives the point position values. I imagine it can be done in a Wrangle or a VOP. I tried a few things that way, but coming up with zilch. Hoping someone can help a frustrated beginner! File is attached! (WARNING: requires Houdini Labs’ Tree Creator assets to be installed) Preemptive thanks! NpF LabsTrees_Displacement_Test_v001.hiplc
  8. Can I use redshift noise in a SOP as a displacer?

    Many thanks Fred, I got similar responses from folks on the Redshift forum. I will give that a try. Cheers, Nik
  9. Greetings all! I’d like to know if it’s possible to pipe any one of the Maxon/Redshift noises into a SOP node in order to displace geometry on a mesh (rather than having Redshift handle the displacement at render time). I need to do this for the following reason: Maxon/Redshift has the specific noise I want (don’t want to spend a lot of time trying to replicate or approximate using one of the SOP noises). I will need to generate vine growth along the object I will be displacing with noise, so unless I’m mistaken, using render-time displacement is not an option. If there’s some workaround to this I haven’t considered, please enlighten me!!! Preemptive thanks for any responders! NpF
  10. Karma Noob Issues

    @davpe I appreciate your response. I haven't had the opportunity to run any benchmark tests but there does seem to be a little debate on the SIdeFX user forum about the advantages in render speed (Mantra vs. Karma). Seems a few folks claim there's a substantial speed advantage (though Karma couldn't compete with any of the upmarket GPU renderers frame-per-frame). In any event, I started experimenting with Redshift in the meantime and I'm totally sold so far (it's actually part of my regular workflow using C4D). In any event, after some stabbing around and thanks to @Atom's suggestion above, it turned out that the issue was that the Karma (and Mantra) components of my license were being blocked by firewall. Something to do with Karma, I guess Cheers and thanks again, NpF
  11. Karma Noob Issues

    @Atom Many thanks for the response. It's been a while for me with Houdini so I didn't think to check if all licensing was intact, so thank you for tipping me off. Upon your suggestion to "recover (the) render token", I checked Houdini's License Manager app and sure enough the Mantra and Karma licenses were being blocked (presumably by my Firewall blocker app). I went ahead and adjusted firewall and then did a re-download of all license components, a quick reboot, and voila, I'm now able to render using Karma! Many thanks again! Nik
  12. Karma Noob Issues

    Hello all, I’m returning to Houdini after stepping away for a bit, and figured I’d brush up a little by giving the Karma renderer a spin. While the general workflow appears to one-up the ancient Mantra, I keep running into the same dumb wall, despite going through basic tutorials by three different artists (per this LesterBanks page: https://lesterbanks.com/2019/11/all-about-karma-and-lops-in-houdini-18/) While everything else seems very straightforward (though still possibly buggy) the thing I can’t seem to get to is any kind of final rendered bitmap that is not just a field of black pixels. I’ve tried rendering through every file-type option (.exr, .tif, .pic, etc) and through every render buffer (tried MPlay, Render to Disk, Render to Disk in Background, etc.) but I am only getting black images, no matter which tutorial I’ve followed. Here’s a link to my project structure: https://www.dropbox.com/s/0edzqf0ivr24scx/KarmaKitchen.zip?dl=0 I took to monitoring CPU / GPU activity: While Karma IPR is running, CPU / GPU activity is ~90%+ / ~15%. For “straight to disk” rendering, CPU doesn’t go above 3%, though Houdini’s Scheduler / Render Manager verifies that the computer is actively rendering. I’m not sure if this will give any clues, but here’s a snapshot of the RM during render. https://www.dropbox.com/s/em4bnzcm4rtnd0i/RenderManager.JPG?dl=0 Otherwise, I’m running Houdini’s Indie license, though as far as I’ve been able to research, Karma is compatible with the Indie license. Am I wrong about this? Also, as a general question, is there a hugely significant speed advantage to Mantra? Seems like it might be wiser to hold-off on Karma until it’s out of beta stage. Any thoughts on that thought? Preemptive thanks to any responders! NpF
  13. Creating a geo for a convincing looking cancer cell

    Much appreciated tmdag!!! This is awesome!! I presume you built this network yourself? I finished an extensive Houdini course not too long ago, which covered most vfx basics, but did not explore cloth and/or soft-body dynamics. Before falling down into a tutorial rabbit-hole, I'd wonder if you'd have any suggestions to how I might approach making the tendril offshoots look like they sag a bit in the middle, as if they're made of soft material. My guess would be that it wouldn't be too hard to apply some physical properties and some forces to the linework geo before applying the PolyWire thickness, though i don't have much of an idea which SOPs and/or DOPs would be appropriate for such a thing. Could it be done with a simple WireSolver or would I more likely need to open Vellum for something like this? Many thanks again! NpF
  14. Hi all, Relative noobie here, looking for general advice on how I might approach modeling a cancer cell that looks like this: https://www.mskcc.org/sites/default/files/styles/width_800/public/node/167374/3x2/sciencesource_ss21694540_1200x800.jpg [www.mskcc.org] or this: https://static.independent.co.uk/s3fs-public/thumbnails/image/2016/02/15/21/1-t-cell-corbis.jpg?w968h681 [static.independent.co.uk] One physical feature of the cell that I’d like to pull off convincingly is the sticky-looking tendrils that shoot out from the membrane, that look a bit like viscous liquid has been shot out from the surface of the cell. Though something like the image in the above links would be ideal, I would settle for something like this: https://lymphomanewstoday.com/wp-content/uploads/2018/09/shutterstock_565670083_zps0eglo9ri-1000x480.jpg [lymphomanewstoday.com] I would want to avoid something like this (where the tendrils resemble veins, or maybe octopus tentacles: https://www.segnidalcielo.it/wp-content/uploads/2017/08/GoldNanoparticles.jpg [www.segnidalcielo.it] Since for now I only actually need a static model, my first inclination would be to start with a simple POP setup, have some particles explode off a spherical surface and append a trail SOP to get the tendril trails. I’d run the sim and use a single frame from it as the cancer cells base geo. This only gets me so far though, as there are other important visual details that I’ll refrain from talking about until I some experienced person can tell me that this is definitely the way to go. My other inclination, which I realize might be inviting insanity, is to create a “fluid explosion”, using a FLIP setup with some velocity noise coming from the SOP level, and playing with DOP node settings to get the right kind of viscous/stringy effect from the particles. From there, again, I’d run the sim and use a single frame of geo for the base for my model. I’ve so far made an attempt at this (file attached), though have only tried seeing what I could get by using nothing but some noised-up velocity on the SOP source, some DOP gravity and tweaking settings in DOP Source Volume and Solver nodes, pertaining particularly to viscosity and surface tension (though I’m not sure the latter is relevant). I’m able to get some neat looking effects, but not really the ones I’m specifically after. What I’d wonder here is whether this ‘explosion of viscous fluid with a very high tensile strength’ could even be achieved with a fluid sim, and if so, would I need to push/pull the “sticky/stringy” fluid outward by having the FLIP particles stick to a set of “collision” particles which are then launched outward, pulling some of the fluid along with it. Or, could this effect be achieved by simply applying velocity to a Fluid Source SOP with very low particle separation, and then relying on settings available in DOPs nodes to get the long / stretchy tendrils. In any event, I’m certainly open to suggestions even if they’re completely different approaches to what I’ve described above. Thanks ahead of time to anyone responding! Nik pF CancerCell_FLIPFluidFromObject_v021.hipnc
  15. Detriangulating PolyLoft

    Many thanks, Noobini!
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