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Found 42 results

  1. My first time messing around with Chops outside of just adding some easy adjusting with motionfx. I'm testing it out just trying to move a sphere with some audio, what am I doing wrong? I appreciate any and all help, thanks. My values aren't super small, I feel that they should be noticeable. Here I'm doing " chop("/obj/chop_music_OUT_music/") " is this not the correct way of referencing the node within chops? / getting the audio data ? I feel like I'm making a dumb mistake somewhere but I've been stuck for a few hours, any help is welcomed. If you guys have any links to more recent tutorials covering that topic that would be helpful as well, thanks so much.
  2. creating sound from animated curves

    Hello, I have an experiment where I want to create sounds from a set of deforming curves, like the strings of an instrument. For that I'm driving the pitch control of an oscillator. It works just fine for one curve, and also with several if I set them up one by one. However, in the end I'd like to have a lot of curves and I wanted to get them all in via one geometry node in my chop network. Using the point name attribute in the geometry node I have all my channels coming in correctly. i.e prim_0_pitch1, prim_0_pitch2, prim_n_pitch1 etc. I couldn't figure out how to make use of the channel groups iteration method of the foreach node and ended up iterating over the whole set "over numbers" and deleting all channels I don't want. Sadly I can't feedback like in a sop foreach to get all the channels back again.. I'm stuck and I'd be glad for some hints, or maybe there is a better approach? Thanks in advance! seb soundstrings_test.hipnc PS: Another strange thing - whenever I connect the foreach loop to the out null, the filesize increases to 30mb (from 400kb) and the only way to fix that is deleting the foreach node - in any case, to hear the sound please connect it after opening!
  3. SideFX Houdini Masterclass - Louis-Philippe Clavet Following the Everything Procedural conference, Breda University of Applied Sciences will host a two-day SideFX Houdini Masterclass by Louis-Philippe Clavet. This is an unique opportunity to learn, experience and get acquainted with one of the most versatile procedural content generation tools. Day 1: SideFX Houdini - Procedural Animation Houdini has long been known for its great ability to reproduce the motion of many natural phenomena through its dynamic operators. Even if they are fantastic tools, some movements are hard to generate with these systems. A procedural animation approach seems to be a great alternative to infuse life into a cg scene when artists need more intuitive ways to bend motion to their will. Through skillful attribute manipulations and a clever use of CHOPs, you will experiment what can be put into motion with a limited use of dynamic simulation and keyframe animation. This masterclass is a collection of test scenes built to showcase the versatility of procedural animations in Houdini. It is intended to Houdini users of all levels, but requires a good knowledge of how to navigate the software and its interface. Day 2: SideFX Houdini - Procedural Dependency Graph (PDG) Discover the new context introduced in the most recently announced version of SideFX Houdini. Houdini now offers us a visual management system that handles all tasks and all dependencies in which TOPs (Task Operators) are the new set of nodes tailored to improve workflows and pipelines. Learn how to deal with the challenges of creating and working with a great amount of data. Experiment how this system can also help artists to automate tasks that they do on a daily basis. This masterclass is an overview of the new technology. It is intended to Houdini users of all levels, but requires a good knowledge of how to navigate the software and its interface. The Masterclass is a two-day event (both 9:00-17:00) and takes place on Thursday April 25th and Friday April 26th. The Masterclass will be hosted in a workshop setting with live presentations, demonstrations, hands-on experimentation and exercises. You need to bring your own hardware (laptop is sufficient) to be able to actively participate. http://everythingprocedural.com/ https://twitter.com/everythingproc https://www.facebook.com/everythingprocedural
  4. Error channel Node Chop Network

    Does anyone know why i get this error in mu Channel node i created and attribute , for my chop network? Thx in regards
  5. Hi, I constraint two objects together with chops. Everything works until I use expressions in my parent object. What do I have to do to fetch expression values into chops? kind regards Jon express_chop.hip
  6. Hello peeps, I'm trying to figure out something similar to some sort of ribbon setup in Houdini. Still, lots to do but right now I'm trying to work out rotations, I have twist working by itself such that if I twist the ribbon the bone rotates accordingly and bend working by itself as well, however, if I twist and bend the ribbon at the same time, the rotations become unstable. How can I fix this? Any help is much appreciated!!! Thanks. ribbon_setup_test_01.hip
  7. Hi guys, I'm having some trouble using bone length for squash and stretch as its giving me crazy deformations that I cant fix. (see attached file) if anyone knows how I can solve this, it would be much appreciated. Also, the other problem is, how would I implement volume preservation with the squashing and stretching? In maya, we would use the joint scale but Houdini seems to give weird results if I scale bones. Any help is much appreciated. Thanks. rigging_bone_stretchy_problem_01.hip
  8. My Original Question is still posted bellow, but i have since figured out a solution to get what I want. Basically in CHOPs I have a null with a string parameter with a multi line python expression on it. This expression produces a string with all the channel names in it. refNode = hou.node('/ch/ch1/noise1') tracks = "__TEMPSTRING__" iteration = 0 trackTuple = refNode.tracks() for track in trackTuple: curTrackString = str(track).split(" in ")[0] curTrackString = curTrackString.split("<hou.Track ")[1] if iteration == 0: tracks = curTrackString else: tracks = "{0} {1}".format(tracks, curTrackString) iteration += 1 return(tracks) Just make sure that "refNode" is referencing the node you want to get the channels from and this should work for you as well -- ORIGINAL QUESTION -- Hey guys. I need to be able to the names of all the channels that exist on a particular CHOP into a string parameter field (as shown below). There is a VEX Function called "chnames" which gets me the names but then I don't know what to do with it. I've promoted the names to a clip attribute but I have absolutely no idea how to access said attribute in an expression. So my two ideas are either to... 1) Stick with the Clip Attribute and somehow reference that in an expression OR 2) Somehow execute the "chnames" VEX function in an expression/parameter field (which I don't even think is possible but putting it out there just in case) If anyone knows how to do either of these things or has another method that'd work please let me know. I'm about to explode from the frustration of trying to figure this out!
  9. Hey Guys. I've import some midi files into chops. Each time a key is pressed, it creates a flat peak, and then goes down to zero. So basically I've got a bunch of channels with localised plateau peaks. What I want to do is essentially extend the tops of these peaks until a new plateau is reached, at which point I will extend that plateau out the the next one, and so on. I've gone ahead and done this in SOPs to illustrate what I'm trying to do (cause that explanation above likely made no sense). The pseudo code for what I want to do is: maxVal = value of sample0; foreach sample (excluding 0){ curVal = the value of the current sample; if curVal is equal to 0{ Current Sample Value is set to the maxVal; } else { maxVal is set to the curVal; } } This is the logic I followed in SOPs and it worked perfectly. However I cannot figure out how to do the same thing in CHOPs. My problems are two fold. 1) I can't figure out how to set the value of samples that are NOT the current one being iterated on. The way I've found so far to set sample values is using the global variable V. I tried to do it using the 'chsetattr' function, but either it doesn't set sample values or "V" is not the right attribute to use (and I can't find the correct one). Also tried setting a sample attribute on one wrangle, then on another (with iterate set to channels and samples) set "V" to the value of the attribute. Also didn't work. 2) So far I have found no way of only executing the code once (such as in a detail wrangle, which is what I used for the SOPs example). I thought setting the wrangle to iterate by "Over Channels" would do the trick, as the documentation says, "Runs the snippet one time per channel with the I variable set to zero." but in this this post Guillaume points out that this isn't the case. And even if it was I still would be in trouble because that mode does allow setting "V" or channel data. 2.5) On that note, whats the difference between channel data and attributes? One can be written the other can't. I thought attributes were just data stored on the geo (or in this case channel). Not sure why CHOPs is suddenly making a distinction. So to summarise, I need to find a way to set the values of individual samples and I need a way of executing a CHOP wrangle once per channel (like a detail wrangle in SOPs).
  10. CHOP's Frame limit

    I am in the process of setting up several camera rigs following the same piece of geometry with lagged "look at" constraints. The lagged Nulls I have made the camera "look at" only behave as they should up until frame 240, after which they stop moving completely, despite the scene length being 1000 frames. I have attached the .hip file, any suggestions are much appreciated. Thanks! CHOPsBug.hipnc
  11. I have an animation channel with keyframes with various integer values. In CHOPs, I'd like to have a rolling counter that holds the sum of values on all preceding keyframes (values from keyframes only, not values from all preceding frames). Any idea how to do this? Below is a sample of what the counter would do: Keyframe on frame 1: value 3, counter: 3 (3) Keyframe on frame 8: value 8, counter: 11 (i.e 3+8) Keyframe on frame 13: value 4, counter:15 (i.e 3+8+4) Keyframe on frame 23: value 4, counter:19 (i.e 3+8+4+4) Keyframe on frame 29: value 7, counter: 26 (i.e 3+8+4+4+7)
  12. I am trying to re-create a ribbon deformer in houdini that takes transformation and rotation data and, using interpolated values transforms a bone chain. I have linked controls to a surface, and extracted a line from that surface with what I think is the required data. I am not sure how to take that data from a geometry level and apply it to a bone chain. I assume chops is the way to go but I don't have any experience with them.
  13. Hi everyone, I'm trying to create a delay effector style effect on some copied boxes, but I've chosen the option to pack primitives before copying and now in CHOPS I want to know how to make say a Spring CHOP pick up the rotation of a packed prim. Here is an example scene file below. Thanks to anyone who can help. C4D_mograph_rebuilding_01.hip
  14. Music Visualisation

    More info here: http://simonfarussell.com/The-Creatures-of-Prometheus
  15. MIDI Automation Channels

    Does anyone know if there's a way to bring in automation channels from MIDI (eg. volume, pan, fx controls) from MIDI files (not realtime)? I thought it maybe the Control tab in MIDI In but I've had no luck. Thanks, Simon
  16. Hello I am trying to do something really simple and I am finding it to be quite hard. I am trying to rotate a box so that it carries momentum and settles down naturally as if it had mass. I have included a .hip file where I have attempted to do this manually but it is not the best. I am struggling to get the animation editor to behave and I have to keep closing and reopening Houdini as the Animation editor and the viewport are not marrying together. If anyone knows why this is or if there is a better way of doing this, (I have tried motion fx (spring)/chops but it failed miserably) I would be very appreciative. I have come a long way in this wonderful program but for some reason the animation editor feels really clunky in comparison with the rest of the program and I don't know if it's something I am doing wrong. Thanks dampened animation.hip
  17. I have a simple audio react animation that is conneceted to a CHOP network, just a few polygons with a simple extrude based on an audio trigger. However I want the objects to extrude sequentially; on the first audio trigger primitive 0 will extrude, then on the second prim 1 will extrude, so on and so forth, but have it be sequential and based on the audio trigger from chops. I attached a simple hip file, any help would be greatly appreciated Chops_sequential_ODFORCE.hip
  18. Audio affecting particle position

    Hey all I'm quite new to houdini so please bare with me. Is there a way to use an audio output from chops to change the position of a particles? Can I do that by using a pop vop? If so, how can I import my chops output in there and add it to the position of my particles? Is there maybe a better solution for that? Thank you!
  19. Chops increasing value

    Hey, I was hoping someone could help me out with a CHOPS set up I'm stuck on. I'm looking for a channel to continuesly increase over time at a set rate, but with added intervales? That may no make sense so I have set up a scene to decirbe it. The image below show the white line which is what I'm after. Its a mix of the red (contast increasing value) with the sine wave pink line, but only the positve values, which then get added to the red line. Sorry if that's confussing, CHOPS is confussing! Any help would be really apprciated! Chops_Increase_01.hip
  20. Hi everyone, I'm trying to figure out a way I can offset a keyframe by a channel value. For example, I want to animate the uniform scale on a sphere but I want to be able to control the start frame of the animation by a channel value. I'm sure there is a way you could do this in CHOPS, but I'm not very comfortable using CHOPS, and thought there must be a simpler way of doing this! Thanks in advance
  21. Hi ladies and gentlemen, boys and girls, I have a job to create a kaleidoscope animation. I'm just learning how a Kaleidoscope works in real life and time is limited. Has anyone ever worked on such a project and can give tips on how to get started and maybe some math behind how it works? I've attached a video I found that has this effect created by buck (starting at about 16 seconds in). Any help here would be much appreciated really. Thanks in advance. Sherwin Williams - Kaleidoscope-SD.mp4
  22. I am trying to make some hda's to help speed up and distribute my mocap cleaning process, however when I make an HDA in CHOPS I get an error saying the sub-network has no output, and when I go to edit operator type properties, sure enough the outputs are greyed out. Anyone have an idea on how to fix this?
  23. Hi... I'm looking to attempt some image manipulation using CHOP nodes. Having used the Image CHOP to access the individual pixel data I'm lost on the best way to Export it back to COP context. I'm guessing I could do it with the VopCop2Gen COP, but thought their might be a better (easier) way? Cheers!
  24. Hello everyone, I wanted to transfer my animation from DOPs to SOP level, but I need to have a baked Curve. I managed to make a transfer between CHOPS > SOP using dynamics and export in CHOPS, but when I click Edit Data Channels and then Fit Panel > Copy to Export Destination (9 channels), I got a message "Status: 0 channels copied." The connection between CHOPS and SOP still works, I have a curve in Motionfx editor but I can't transfer it to Animation Editor and delete CHOP Network. Please Help.
  25. Hi all, I've been trying to figure out how to create a linear ripple effect (i.e. rather than have a single point as the source, I'd like to source it from a line/selected edge/group of points, so that it travels across a surface like a wave.) Now, of course, at a basic level the 'waveform' SOP node performs this exact operation - *However* it can only generate a single wave at a time, and it lacks the signature 'decay' of the ripple over time. I had the idea of using the wave operation in CHOPS using a sine wave with decay on it, however any changes to the amplitude are applied across the whole waveform, rather than 'at birth'. So it doesn't create a dying wave, it just scales down the whole waveform. (see image). Any ideas on how to achieve this? (just as an FYI, eventually I'd like to control the decay length with an animatable paramater & creation/scale of the ripple from CHOPS with a trigger.) It seems like it should be super easy - Maybe I'm just having a bit of a mental block! :/ Any mind jogging greatly appreciated!