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Found 19 results

  1. Hey, I've a chop network where I'm using a jiggle, I would like control a parameter of jiggle by a point attribute of my geometry. doing this I imported my parameter as channel scoping out from the jiggle operator and using in that parameter this expression chopi("px",$I) assuming to read the name of my channel (px) plus the index of that, or using cop("px", $I). but no one of these are working and I can not acces the index using $I. do you know how to resolve this? or even do you have any jiggle example in chop vex? thanks in anticipate.
  2. Hey guys ! I'm starting out in CHOP, so be gentle. I'm trying some things to get going, and already hit a roadblock. I got a geo node that I'm assigning the rx rotation from CHOP, adding a sin wave to it. Works well. But where I'm stuck is that I'm trying to add that same animation to a second geo node, but I want to add some sort of time offset between the two animations. So I'm thinking "Let's add a timeshift node under the constant, and use some kind of global variable (I believe $C ? Or @C ? unsure) to make a random number for each channel as an offset number !" Sooo, that didn't work. $C and @C doesn't return anything interesting (aka. not 0 or not erroring out). Maybe I understand this wrong ? If so I'm unsure as to how to use those global variables. Also, as a side note, I've seen chan[X-Y] being used sometimes in videos, but didn't find it in the help. Nevermind found it, gotta learn to use it now. It's in the Common parameter section of a lot of CHOP nodes. So ! Is the idea wrong ? How should I approach this ? Thanks in advance ! chop_timeoffset_test.hip EDIT : P.S. I've just noticed that in the help, it says When processing multiple channels, [...]. So I believe placing the timeshift under the math node would be more appropriate. But even doing so it stills errors out. Also, there's this - but I haven't been able to make it work. I tried the different combinations of Reference and Unit Values, to no avail.
  3. I am working grooming some curves/hairs and all the way below the chain is a chop node with noise inside a subnet, even do I bypass the subnet, every time I change something takes forever since the chops cook even do that I think they are off/bypass, all the frames =( is there a way to really by pass chops or just let them cook by frame so the scene??? is kinda annoying =(
  4. How to compute timewarp from nuke

    I have sim cache in linear timespace and a timewarp curve in .chan file from nuke, and I want to get difference of time change from it to use as a multiplier for increasing velocity in motion blur. For now I`m stuck on my on e solution: I use slope node on timewarp to calculate the differences in time change, but I`m not sure that this is a right solution. frame_camera_expChan.chan timewarp.hip
  5. Does anyone know how to read channels from CHOPs without jumping through the whole Geometry CHOP -> Channel SOP hoop? I have a CHOP network with 1 channel, and I want multiple objects to use the data in that channel in different ways. So instead of making a new CHOP network for each object, I'd like to just keep the one network and have the SOP networks go and "grab" the data as needed. Something like the 'chinput' VEX function but for SOPs would be perfect! I need to be able to grab the data at different times/samples depending on a point attribute, so the method of using a 'chop' expression wouldn't cut it. At the moment I've got a line with as many points on it as there are samples, then transferring the channel data over using the standard method, and then sampling the values from the points on that line. This method works, but feels quite clunky.
  6. 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
  7. Hello guys! i need to create a channel based on a table (csv file), the table looks like: (id can be ignored) id myvalue 1 509 2 514 3 519 4 524 5 529 6 534 7 540 8 544 9 550 10 555 i wish create a channel with a key value of 1 on every myvalue, and 0 in all other frames (basically a 0|1 toggle), this way: frame value 1 0 2 0 ... 509 1 510 0 ... 514 1 ... i try everything..but no sucess... any ideas??? thanks in advance!
  8. I am trying to animate an engine using chops and constraints. I manage to get something quiet close but it isn't accurate(cheat) My main issue is that i cannot find how to use a "look at" in conjunction with some restriction to force the tip of the arm to slide along the Y axis. I tried many other solution as well as trigonometry(which i am not very good at) which i gave up on. i also tried with bones but again my knowledge is close to none in houdini and i wasn't able to restrict bones I wish to achieve the real thing with your help Thank you piston.hip
  9. Introduction to CHOP's in Houdini FX

    My latest commercial training in Houdini about using CHOPs in Procedural Animation , Hope you Like it more info here : http://www.hossamfx.org/chops-in-houdinifx/ Hossam aldin Alaliwi www.hossamfx.org kind regards !!!
  10. Hey, could someone help me building this curve in chop ? I need a curve, a noisy curve with a positive slope. I managed to do that with a pulse (set up to get a positive slope) and adding a noise to it. But the final curve I need has to be like this : (never going down)
  11. A small experiment, where geometric models are turned into sound. More info about the process at ch3.gr/geophone I love the geometry CHOP node! =]
  12. CHOP Channel value after deletion

    Hi all, I'm trying to filter the jittery movement on dynamic geometry, so I thought CHOPs is the way to go. This generally works until points are deleted, when I noticed they flew off towards their start location. This is being caused by the fact that, when a channel is imported it's value reverts to it's start value for some reason. I cannot find any way to just make this value continue from the last good value just before the point was deleted. The reference image shows some channels where I point out when in time the point was deleted. Why on Earth does the channel then revert back to the start value after this point?
  13. Hi, I have two file nodes and I am animating a switch between the two at a certain frame. I am then taking the output to the speakers, but it doesn't seam to respect the animation of the switch and it just plays the first selection even if the waveform changes on the viewer. Is there a way to force it to update the audio on every frame? Any animation is also ignored when I save out the waveform to disk. Any ideas? thanks
  14. Hi guys, I am still working on my boat and I would like to alter the animation. In the detail, I would like to "rotate" the boat a little faster when it hits a wave, so I think that the better way it would be to alter the "x" rotation (in orange). I would like to obtain the result you see in white. I think the way is to alter the channel values in the CHOP network but I don't know which function to apply or, if it is possible to manually alter the lines. I tried to use the "math" operator and multiply the values for 1.5 but it only increases the degrees of rotation and it's not what I want to achieve. Imagine a boat that gets a wave: it rotates up very fast, then "rests" and then when it hits the sea inverts the rotation and then rests again... Since my animation was created by the projection of the boat to the sea waves (with some filters and lags), it is too linear... Thank you for your help. Cheers! Lazza79
  15. Hi! I have a CHOP channel containing some values and I would like to select only a few values at specific samples to then interpolate between them. I have attached a scene where the node `SAMPLES` needs to be used to select the values from `VALUE` to interpolate from. The node `DESIRED` represents the final result that I am after. I'm getting this result by manually creating constant values to interpolate from but it doesn't seem possible to do this procedurallly based on the nodes `VALUE` and `SAMPLES`? Also the process needs to be fast so I would like to avoid using `ic*` expressions if possible. Any idea? Thanks! chop_interpolate.hipnc
  16. Paint on Speaker WIP

    This is a WIP of what I've been doing on my spare time. Hope you like it! Comments and Critics most welcome
  17. Hi all, I have been using the Pipe In chop and recording it with the Record Chop. I am now trying to save the data as a '.bclip' by right clicking the record chop then, save data channels. I get to choose the location, name and type. But when I click accept is says 'save failed: unknown reason'. I have tried all the different formats and saving it from chops further down the line. Also switching on and off the export flag. Has anyone had a similar problem? Is it a licensing thing? Any help would be appreciated. Thanks.
  18. Hi! I'm currently having a big problem converting my tool into an OTL for use in Maya through the Houdini Engine. I use Chops in the tool and mainly the Foreach_Iteration node is giving me a hard time. I've already searched through quite some forums, but so far no luck. Also, so far, I haven't seen anybody else with the same problem. I've created a test file for this issue to show you whats going on. Mainly any tool, which uses the foreach chop, doesn't allow me to convert it into an OTL. The first error that I get is about the use of absolute paths. But when I fix this (delete the Export Prefx (../../..) in each chop node) I'm still getting a "Missing token" error: Error: Missing token : "{ subnet1/chopnet1/foreach1/Foreach_Iteration". Can someone help me with tackling this issue? Thanks in advance!! ChopsInOTLTest01.hipnc
  19. just a little test of CHOP's in Houdini. The sound sample isnt best for this kind of stuff, but i like AC/DC
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