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Found 56 results

  1. Hi all, i've got some points with trails and i'm filtering them randomly to leave some behind as the trails move forwards. each trail is split into a leading point and the trailing points, and each trail and its leader have a unique id. what I want to do is take the points i've left behind and remove them if they come into contact with another point trail that has a different id. so something like an attribute transfer but with a condition that checks the near points id and only transfers some attribute if that id is different. so the white points from trail 1 would exist until the come in contact with the red points from trail 2. Any ideas how to do this in vex or vops? Many thanks,
  2. Finished my first tutorial, hopefully you find it helpful learning Houdini!
  3. I need help I newly started with Houdini and doesn't know hot vops and vex works and I want to create a line where the normals are pointing in a different direction while keeping a 90-degree angle to the line. I fount a tutorial on the internet which only make the normals point in a random direction but not in the 90-degree angle I tried to set the normal direction to zero with floats and stuff but it always results in vex errors. @N = sample_direction_uniform(rand(@ptnum)); rand nomrals.hip
  4. Hi everyone, Can't seem to be able to find a good logic behind why in Vops if you plug -0.1(dividend) and 1(divisor) into the Modulo node, the result is 0.9 instead of -0.1? Thanks.
  5. periodic Noise Zoetrope

    hey guys, do you ave an idea how to achieve this effect ? https://www.wired.com/wp-content/uploads/2014/06/ezgif-save.gif it's a zoetrope with noise basically it's a rotating sphere that spins really fast, which placed under a stroboscopic light looks like it's animated; i wanted to recreate the exact physical setup, not just an effect overtime i created an attribute vop with a unified noise set to periodic so it loops, but i couldn't figure out the offset per rotation just yet this guide is quite useful to understand the principle,... https://www.instructables.com/id/Blooming-Zoetrope-Sculptures/
  6. Hi, reformulating my question from my previous post: If I have a VOP net animating the positions of a plant mesh with a noise, how do i blend back to a rest position at the end of my frame range so that the animation loops? I've tried the blend shapes node with a time shifted version of the noise but i don't get any transformation.
  7. hello there! I have a procedural noise in mat context and I want to assign the output of the noise to point attributes of the surface. how can I do that?
  8. I'm trying to create a pipe HDA for Unreal Engine 4 that either calls upon a straight piece or a corner piece and then orients each piece accordingly. I feel like I'm going about it all wrong, but the result I have is so close! As you can see in the first picture, it's KIND OF working, but I think it might fall apart very easily. I've attached a hip file any help would be greatly appreciated. pipeorient.hip
  9. After setting up the rotations for packed objects in point vops (after scattering), I just couldn't do the same for scaling and translating. I want to find a solution for cases where the scattering has already been done (or there are many instances of the same object). Can some one help me out? Bellow is the hip file. packed_objects_debug.hip
  10. gradient r&d

    Hi all, I'm approaching something in H/Redshift which I've not really attempted before - So was interested to see if there were any thoughts surrounding it. Basically I'm trying to recreate the soft/feathered gradient seen in the attached ref image. The inner hard edge I'm planning to achieve with some transformed geo floating above the grid below, however the super subtle feathering is challenging me a little. At first I though of using a simple attribVOP on a grid > point Cd. However I'm nut sure how to achieve the outer feather using that technique... Similarly with an attrib transfer from geo > grid it seems not very feasible to get the extreme feather unless the mesh is crazy high res? I'm continuing to experiment & look through forum threads, but if anyone has some suggestions/tut links/examples etc. would be very much appreciated! (Worth noting system = H17.5.258 & RS 2.6.43) Thanks in advance!
  11. Hi, I try to offset a texture with a For Loop in a shader. In the example file you can see I iterate 5 times and offset the texture 0.1 units with each iteration. Is it possible to combine all of the iteration steps and show the result of that in the rendered image? Like in the attached picture where I painted in the desired result with red. kind regards Jon forLoop_VexBuilder.hip
  12. Hey, I'm working on a building generator and I can't find a way to align my windows properly when the base shape of the building is oval. When it's a circle everything is okay : But when the shape starts to be oval, it looks like this : Here's the vop network I built to align it with a circle shape, but not functionning with an oval shape : I don't know what I miss to get it working... Cheers,
  13. Distance fall off

    Hi I am doing the entagma tutorial where he is blending from low poly to high poly object. In their example they are using a single point from a sphere to create the blend as in the image below . I would like to use a piece of animated logo to reveal between the two. Using bit of vex I found on this site I think I am getting the distance from sphere to each point on the grid but when I visualise it as Cd. It only seems to be taking a few points into account. What I expect is black circle around the sphere. Thanks finddistanceB.hipnc
  14. Hi guys, I'm building a volcano with chunks of debris flying out the top. I figure I'll just copy rock geo onto points emitted from a popnet. My understanding of vector math/manipulation and control is pretty atrocious; being a visual learner, I'm trying to focus on vops for now, even if the same thing could be accomplished in one line in a wrangle. I was wondering what the best way would be to assign random vectors to points. This is how I've attempted it: https://imgur.com/a/XAQ9ZCk However, when run through the popnet, they all seem to bias to the right, displaying a lack of randomness. From looking at the vopnet, is there any reason why this would be? Without adding a noise, would you guys have suggestions for a better method? I'm not against using a noise, I'm just trying to understand what's going on, and why my current set up is failing to randomise effectively. Also, does my fit range seem appropriate? It looks weird to me, but the defaults were no good. I've attached my hip just in case any of that is unclear. Hope you can help me out; Being an absolute ditz, Houdini math breaks my brain... vector_control.hipnc
  15. KNITTING MORPH IN VOPS

    Does anyone know hot to build a morph vop like this? ITS ON 15:45 Just the transform from the one into the other shape
  16. VOP NOISE NOT WORKING

    Hello dear forum, can someone explain why my vop noise in the end created nothing? Thanks in advance Ground_Study.hip
  17. Attached are two screen grabs. One is a vops set up that works to convert @N to @v. The other screen grab is my failed attempt to recreate this with vex. what is wrong with the vex? Thanks!
  18. Import attribute into VOPS

    So I started watching this excellent tutorial about creating a spiderweb and got 3 minutes in.... https://www.youtube.com/watch?v=LFkzD9cgxek It's over my head with the coding at the moment so I thought I would try to create the same with SOPs and a bit of VOPs. I got pretty far pretty quick, and everything works so far (some dodgy maths, and weird values that work), but I am stuck on the VOPs bit. I want to randomise the rotations for the spar angles, I have them setup as primitive attributes, each one having a different number. I can get the attribute into VOPs (I think), but I'm pretty stuck at how to implement the randomisation per piece/attribute. Any help appreciated. HIP file attached. ) spiderweb_v002.hip
  19. What XSI | ICE "Project a vector" equivalent on POP/VOPS? reference: http://download.autodesk.com/global/docs/softimage2014/en_us/userguide/files/iceref_Project_Vector.htm the node on XSI returns 3 things: RESULT LENGTH VALID any ideas? thanks in advance!
  20. I have 2 sets of points: 'parent' and 'child'. Both have the same number of points. I need each parent point to have a unique child assigned to it - no duplicates. I need to be able to animate in an active value for the parent points, so that they all become active in 3-4 frames. When a parent point becomes 'active', it needs to search for its nearest available animated point and set that animated point's id number as 'child_id'. An animated point is only 'available' if it doesn't already have a parent point, or in other words: if the child_id is currently unused. My issue comes from the VOP I've set up within a SOP solver. If there is more than one parent point becoming active on a single frame, I get multiple parent points assigned with the same child point. I need to be able to write to 'child_id' and read from it on the same frame, to make sure that I am not getting multiple parent points with the same child points (leaving some very lonely, parent-less child points ). Please take a look at my attached file. I've highlighted the important nodes, and the Find Attribute Value VOP in red is where the issue is originating. find_unique_child.hip
  21. I am trying to make a setup where I align an object orthographically and then after I do my operations move the result back to the original position. I have a working way for aligning but am sure there must be an easier way... My method for aligning now: - Create oriented bbox - Measure prims - delete all but largest, then delete 1 of the largest in order to just have 1 rectangle, 4 points - make a vector from point 0 to 1 to align with x - make a vector from 0 to 2 to align with y - make normals to align with z - in vops use the align vop to align the 0 1 vector to x then use the (rotated) normals to align with z Even though this works I assume (hope) there is a better way to find the vectors, using pointnumbers is not procedural enough imho so any tips here would be great. But then the part I can't seem to get... How do I rotate my result back to the original position? there must be a way to store the rotations and invert these or something but everything i tried didin't work. my vectormath and matrices could def use some work. ofcourse i can use a point deform but that would not be accurate enough plus i am 00% sure there must be a way to invert what i did in the first vop. Thanks!
  22. I Speak Whale - Houdini Project

    Hi guys, i would like share with all of you my latest personal project i did on my spare time. Hope you like it.
  23. Hi, I am trying to calculate the y distance of a cached fluid sim in a tank. and I would like to have a color going from from black at the bottom and white at the top. The idea is to then use this in Mantra to drive the roughness of the transparency or the tint to create an ocean shader. I am trying to do this using a vopsop, I have tried various methods that other people have tried and I can only get it partially right. most of the time it seems to be calculating the distance from the center rather than the Y distance. In the file attached I get the gradient at an angle rather than straight up. I am totally new to this and any help would be appreciated. points_from_volume.hip
  24. I was looking at the ripple sop and wanted to add some extra noise, I found that you can't just dive inside but it is compiled vex code so I figured it can't be too hard to recreate. Well I got pretty close but for some reason I am missing the high frequency displacement the original ripple has. Attached is an example of the ripple Sop vs my pointvop I guess I'll post the whole code first and then point out where my struggle lies: #include <math.h> #pragma oplabel "Ripple" #pragma opname "ripple" #pragma opicon SOP_ripple #pragma opmininputs 1 #pragma opmaxinputs 1 #define random0(xxx) (random(xxx)*2.0 - 1.0) #pragma label usecenter "Use Center" #pragma label t "Center" #pragma label freq "Frequency" #pragma label height "Height" #pragma label decay "Wave Decay" #pragma label scale "Scale" #pragma label speed "Wave Speed" #pragma label nripples "Num. Ripples" #pragma label seed "Random Seed" #pragma label up "Up Direction" #pragma export freq all #pragma export height all #pragma export nripples all #pragma export decay dialog #pragma export scale dialog #pragma export speed dialog #pragma hint usecenter toggle #pragma hint t vector #pragma hint up vector // Direction vector #pragma disablewhen t { usecenter off } #pragma range nripples 1 10 #pragma range decay 0.01 10 #pragma bindhandle tx xform "Center" tx #pragma bindhandle ty xform "Center" ty #pragma bindhandle tz xform "Center" tz #pragma bindhandle usecenter xform "Center" onoff #pragma bindhandle height ladder "Height" parm0 #pragma bindhandle scale xform "Scale" sx #pragma bindhandle up1 vector "Up" vx invisible(1) #pragma bindhandle up2 vector "Up" vy invisible(1) #pragma bindhandle up3 vector "Up" vz invisible(1) #pragma bindselectorreserved vex_group points "Ripple Points" \ "Select the points for Ripple and press Enter to complete" \ all 0 "" 0 0 1 sop ripple(int usecenter = 0; vector t = {0, 0, 0}; float freq = 1; float height = 0.15; float decay = 0.75; float scale = 1; float speed = 3; int nripples = 3; int seed=0; vector up = {0, 1, 0}; ) { float xc, yc, phase; float dist, len; vector pos; vector origin; vector offset; int i; if (usecenter) { origin = set(scale*random0(seed), scale*random0(seed+1000), 0); offset = t - origin; } else { offset = { 0, 0, 0 }; } for (i = 0; i < nripples; i++) { xc = scale * random0(i+seed); yc = scale * random0(i+(seed+1000)); phase = M_PI * random(i - (seed+1000)); pos = set(xc, yc, 0); pos -= P; pos += offset; len = length(pos); dist = height * exp(-decay*len) * sin(len*(freq*M_PI*2) - Time*speed + phase); P += up * dist; } } I am thinking the high freq noise is coming from the phase and there seems to be a distinction between random0 and random xc and yc are being generated with random0 and phase with random. Also if you look at the code in houdini the random is colored blue (whatever that means.. I always wonder what all the colors mean but I guess that's for another post) This part of the code: xc = scale * random0(i+seed); yc = scale * random0(i+(seed+1000)); phase = M_PI * random(i - (seed+1000)); How do I translate this into VOPs is the big question for me. Thanks in advance!
  25. Hi all! Posting this challenge here means i've spent a lot of time searching for a solution at this problem, no succed. It's quite simple: You have a set of points, a randomly event occurs for each one of them and once that happens I want to set the frame of the incident into a point attribute. I think is simple but i've been stucked for a few days, hope you guys can find a solution and bright me one more time. Thanks! I attach an example (failed) file. setFrameIntoAtribute.hipnc
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