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Found 91 results

  1. How to add color gradient through velocity plus collision to influence color velocity? to influence the color such as this one here: https://vimeo.com/59024762 how did he do, but he used xsi softimage. if possible to make a Houdini?
  2. Hi, I'm trying to add noise to this curve falloff animation. Currently it's just going straight to the bottom. I want to add a little bit of noise to it. I have used resample node to generate curveu attribute. Can anyone please help me? I've attached the scene file. curveu_noise.hip
  3. In the file I try to create the custom velocity with noise over time using normals. At first I did it with AttributeNoise, things go smoothly. Then I try to recreate it with Vop node, I can't have the normal distribute equally in all the direction like how I did with AttrNoise. Plus it move very fast over time, how do I reduce the movement of it. Also, can anyone show me how to do it in vex too. I add @Frame in vex, everything move in super speed. Thanks in advance. customVelocity.hip
  4. Hello, I have a few questions about vop nodes in mat context. I have no trouble with vops in sop, but things seem to fall apart in /mat (FYI I am working inside a material builder). 1. Is it possible to access @ptnum and @primnum? It doesn't seem to work 2. Some binds just don't seem to work. If I do the same bind in /obj vop context, it works perfectly, but binding it in /mat material builder doesn't. Why would it not work in the /mat context when the nodes are the same? 3. If the vop asks for a file and I use op: to get data from a node in /obj, it does not work and says error finding geometry. But if I do the same thing in /obj in a vop network, it works perfectly fine 4. In /obj in a vopnetwork, you can access the input from the geometry vop global parameter node. If the vop node asks for a file, you can wire it into opinput 1. How do you do that in /mat? What if I want to access the geometry to which the shader is applied? It's asking for a file, but I just want to use the geometry to which that shader is applied. Thanks
  5. Hello, So you know the import point attribute in vops? It asks for a file, right? Well I give it a file in my first photo and it prints no data and the color comes out black. That makes no sense at all. In the second photo I loaded that very same file using a file sop and plugged it into the second input of the vopnet, but in the import point attribute I used "Second input" instead of "file" and it works. Why is that? It's literally looking to the same file. Thanks in advance.
  6. Learning Houdini on Twitch.tv

    Hello! I'm starting a twitch dot television channel and will be streaming Houdini training content. I've worked at several large VFX and advertising studios as well as taught Houdini classes at Academy of Art university. I'm hoping I can reach a larger audience through Twitch as well as the idea that people viewing the stream can participate by asking questions and providing feedback in real time. This is my channel: https://www.twitch.tv/johnkunz My first stream will be starting on Sunday (Jan 26th) @ 1pm PST. If you follow my channel (it's free ), you'll get an email notification whenever I start a stream. I'll be going over this project I recently finished https://www.behance.net/gallery/90705071/Geometric-Landscapes showing how I built things (VOPs, packed prims, Redshift render) and why I set things up the way I did. Some of the images I made are shown below. Please come by this Sunday with any questions or ideas you might have!
  7. Trying to find some info on applying quaternion rotations without using the copytopoints @orient point attribute. I build my quaternion, and then I'm stuck on doing two things: -Applying the rotation to an unpacked object and a packed object I've tried the rotate by quaternion VOP with unpacked geo and the makeinstancexform for packed geo and nothing seems to work this way... I've done some research but didn't find anything usefull (outside of copytopoints @orient). Can some one point me in the right direction?
  8. Hello! Thanks in advance for the help... I have an alembic object that is animated, and I have added a VOP Noise node to stylize it. The problem is that th enoise is setted up at world scale, and when the geometry moves, it doesn't have the noise pattern stuck onto it. I would need the noise to be in object space, and I don't know how to set it up. I've been doing research for days and I've com across to a posible solution, but it is not 100% exact. I have attached some pics of the current setup and where it is giving me some errors. Thanks!
  9. Hi all, I've been practicing and experimenting with VEX in Houdini and I challenged myself to see how far I can go with only VEX and VOP. I did successfully manage to create this simple effect without any use of dynamic simulation (DOP). https://vimeo.com/375250070 Basic Summary: A particle system that computes at frame-basis. I can jump from frame 1 to 700 without waiting for simulation. Instead of the traditional age/life computation, this system uses travel speed to compute. Trajectory generated with polar coordinate + Flow Noise on sphere section. The graph mainly consist of VEXs. There's still room to be improved definitely, if anyone is building more upon this, please share it, would love to see it. I think at the end of the day, this kind of system is probably not entirely practical tbh, but it's a great practice and study on coding with VEX. (SHOUTOUT to a best friend of mine who's studying mechanical engineering, helped me to find a way to calculate the spiral length.) HIP file here: FX_Rasengan_v01.hipnc Happy Coding!
  10. Hello, Can you please help me a little bit? I would like to animate the direction of my normals based on the anti aliased flow noise in point vop. Can you tell me which nodes should I use to get this result? Thank you
  11. Custom Velocity with Volume VOP

    Hello there, I'm making a classic Ship Sailing Effects (ocean guided). I'd like to add a custom velocity to the bow of the ship in order for me to have a good turbolence like this: Through a Volume VOP (please see the hip attached) I created the following velocity: The shape I had it's what I want (straight velocity to the front and curved ones along the sides of the ship, so they can push the water for having a classic V shape). However, I'd like to invert the value of it: having higher velocity in the center e gradually less on the side. With my solution I have to much velocity on the side and less on the center of the bow. Basically I need the trails to be red (high) at Z=0 and blue (low) at the Max Z bbox. Furthermore, is my solution right? I blast a part of the bow, scattered it and then use a Volume Rasterize Attributes for creating the velocity. And, lastly, what kind of operation do I need to use in DOP in Volume Source? Somebody says "Add", somebody "Pull". What is the correct way? I hope you can help me. Any suggestion will be really appreciated. Ship_Body.obj Ship_Custom_Velocity.hipnc
  12. Curl Noise functions in voplib.h

    Ahoy there!!! A quick question... I'm writing VEX noise functions but is a bit confused with Curl Noise functions. It's not like that I didnt get it. Of course I get it but is stuck in this weird functions in voplib.h. Here's what I'm stuck with.... Down below is the Code. why is xDiffNoise yDiffNoise and zDiffNoise there anyways. I couldnt find a function that's making use of it. Maybe I'm missing some. But please somebody explain it to me. Just to say... I'm writing a Curl Vex Function with all the Noise options. Thanks. noisevec = onoise(pos*freq - offset, turb, rough, atten) * amp; xDiffNoise = onoise(xDiff*freq - offset, turb, rough, atten) * amp; yDiffNoise = onoise(yDiff*freq - offset, turb, rough, atten) * amp; zDiffNoise = onoise(zDiff*freq - offset, turb, rough, atten) * amp;
  13. Hi All, I'm looking for some help. I'm digging into shading VOPs and want to set some conditional switches. Unfortunately, I could not find relevant references for this particular case. I want to check if the Texture node (Opacity) has a valid link and switch to a constraint if not. Two-way switch is set to RGB color. It does not work the way I thought it should. What do I miss here? Maybe is there another, more obvious way to achieve it? Thanks a lot!
  14. OceanVortex question

    I'm trying to simulate WaterVoltex with Houdini. This is a tutorial on sidefx that is not ours but a credible site. I do not understand, so I ask here. I have set up like a video but the results are not the same. Heap files and video links, I'll leave time Thank you for your help. The reason for this simulation is to create a water simulation using the ship. I will attach a reference video on this If you have any other approach, welcome any way. I will show my enthusiasm to learn Houdini. Thank you for your interest. Plz.. Related Videos Link (19:21 ~ 25:49) Reference Video (4:21 ~ end) voltextest.zip
  15. Hello I am trying to mix/combine the density and colour of two different VDBs into one VDB in Houdini (image 1, file attached). For the most part, this is working as desired but there are two main issues: 1. Pink fuzzy edges around the blue VDB - How do I get nice clean edges where the blue VDB smoothly fades out to transparent? (image 2) 2. Blue VDB does not go all the way to the border of the pink VDB - How do I make sure both VDBs finish on the same outside border? (image 3) I have tried adjusting the voxel size, changing the set up of the VDBs (ie. the exterior/interior band voxels, fill interior) but I can't seem to get it working the way I want. Can anyone please help me? I have only been learning Houdini for just over a month so example files would be helpful. Thank you! Mix VDBs.hip
  16. Non-Simulated Flame (+hipfile & notes)

    Thought it would be cool to share some R&D i worked on for creating a flame FX without doing any simulation purely through deforming geo. A pretty simple FX nothing too crazy but i though i should share it as some people might be trying to do similar things. I've included the Hip file as well as notes explaining the vop workflows. I'm very much a novice to Houdini's more technical side so excuse any rookie mistakes, critique welcome as well if you think i can improve my workflow. Non_Simulated_Flame.hipnc
  17. how to import point (attribute VOP)

    Hello guys! Can U help me with small problem? I dont know how to import all of the points from scatter to attribvop (to get to an same gradient for all of them)?? Can u give me any advices? Thank you so much! hip. hile in attach how_to_import_all_points.hip
  18. Hello guys! Can U help me with small problem? I dont know how to import all of the points from scatter to attribvop (to get to an same gradient for all of them)?? Can u give me any advices? Thank you so much! hip. hile in attach how_to_import_all_points.hip
  19. hello, i have a curve in 3d space with an organic shape and i want to resample it so it becomes jagged but maintaining its features. So i was thinking i should compare the tangent value of each point with its next one and if the difference is big it means the curve is changing direction so i keep that point. If there is no big change in direction i remove points. But i have no idea how to implement this in Vop or Vex, i am new to Houdini. Any ideas?
  20. I'm running a for-each-connected loop, and need to rotate separate shape such that the largest face is down, for example the one marked L is the largest for the shape in the image. I have a theoretical idea, no clue how to implement it, and not sure if there is a faster or simpler way: (1) get the largest face (no idea how) (2) rotate till the normal of the largest face is facing down Again it's too theoretical, but if you have a way that would turn these flat on they largest face I'll be grateful
  21. Hi, I am just a newbie start learning Houdini. I am following Side FX's tutorials from very beginning. I was watching PWQUINT's 'Sop Solver' tutorial and having trouble. Tutorial show me using SOP Solver DOP to control attribute. So, I did create custom point attribute 'heat' and using for loop and if loop to increase 'heat' value frame by frame, also increase neighbor points' too. There is example file by PWQUIT but For Loop and If Loop vop was different and I tried to follow it with H17 but not working. I cannot find which part I missed. Thank you for reading my question. sopsolver_v001.hipnc
  22. Hi Guys I have a question for chramp function I moved RampValue using Addvop or Add function wrangle worked Look like repeat and vop worked clamp I don't know why two output is different (Left image uses Wrangle Node and the right image uses Vop Node) I think Solution is same , but result is different I wonder why this results chramp.hipnc
  23. Hey! Could someone help me understand this? I have noise going into the vector displacement of a principled shader. Why do I have change the amplitude of the noise in z-axis to affect the y (up/down) position? If I do the same at sop level I can just adjust the amplitude in the y value. I tried messing around with the transform vop, but I didn't get anything working. Thanks displace.hiplc
  24. Hi everyone! I need to do a local rotation using an Attribute VOP for individual points of a grid and just can't get my head around this... If I e.g. rotate along the Z-axis and THEN rotate along the Y-axis it again rotates over the world's Y - not the shifted local Y-axis with a new orientation after i rotated over Z. What I basically need is taking the newly oriented "local" axis into account - the Y-axis should always point upwards from the upside of a cube. No matter how the cube is oriented. I hope you guys know what I mean... i attached an image to clarify. Also I attached a very simple example with 3 Attribute VOPs for rotation over each axis. No matter how the cube is oriented, it always rotates over world-axis. Maybe somebody can point me in the right direction? testrotation.hiplc
  25. I have searched the web for an example on how to use the Rounded Edge VOP http://www.sidefx.com/docs/houdini/nodes/vop/roundededge.html [www.sidefx.com] But was unsuccessful. I have a 3D model which is very reflective and has sharp edges. It looks dark in the environment, because the edges are too “perfect”. I want the edges to be rounded just enough to catch light and reflections. Can any one provide a simple example on a cube? thanks
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