Jump to content

Search the Community

Showing results for tags 'orient'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • General
    • Lounge/General chat
    • Education
    • Jobs
    • Marketplace
  • Houdini
    • General Houdini Questions
    • Effects
    • Modeling
    • Animation & Rigging
    • Lighting & Rendering
    • Compositing
    • Games
    • Tools (HDA's etc.)
  • Coders Corner
    • HDK : Houdini Development Kit
    • Scripting
    • Shaders
  • Art and Challenges
    • Finished Work
    • Work in Progress
    • VFX Challenge
    • Effects Challenge Archive
  • Systems and Other Applications
    • Other 3d Packages
    • Operating Systems
    • Hardware
    • Pipeline
  • od|force
    • Feedback, Suggestions, Bugs

Found 28 results

  1. Hey all, I have some guide hairs in vellum and my orient (point-)attribute which is generated using the guide deform sop is "flipping" (sign changes on orient vector components). This causes the guides to freak out during simulation, showing randomly changing length, jittering and weird behaviour etc. Knowing that vellum needs a stable orient attribute to produce stable sim results, I tried to delete that orient attribute coming from the guide deform sop and instead let it be calculated on the vellum constraint node using "compute missing orientation". The values are somewhat the same and somewhat also different, but I also see some "flipping" orientation values from frame to frame on some guides. If I disable the orient attribute on the guide deform sop (create orient attribute off) and on the vellum constraints sop (compute missing orientation off), I assumed no orient is calculated for my guides, but to my surprise, I still have an orient attribute present after the vellum constraints sop. The even bigger surprise was, that this orient attribute produced a totally stable sim. This left me rather confused, and I hope you guys can maybe shed some light on whats going on here. Why is my orient attribute flipping, how can this be prevented, and what (where) is the best way to calculate a stable orient attribute? I unfortunately can't provide a hip-file showing the issue cause my current project is under NDA, but I still hope you guys can make some sense of what I say. I am using Houdini 18.5.392. Thanks in advance and all the best, Scratch
  2. Instancing tree leaves?

    Hello all, I have a built a rig that allows for the dynamic simulation of trees. I was able to define an instance point which is offset from the trees branches. This enables the copying of a packed leaf primitive onto the point. The next step is to update the rotation of the packed primitive. It seems like the copy to points has defaulted to using the z-axis (vector pointing in the {0,0,1} direction). The tree includes a central wire which captures the deformation as it moves through space. I have been able to construct a normal by using the following logic: Using a leaf point find the closest point of the wire compare point positions (@P{leaf point} - @P{wire point}) normalizing the compared vector and setting an @N attribute VEX CODE However, when using this @N (normal) on the copy to point the leaf geometry picks up this @N (built above in vex) and discards the desired z-axis vector of {0,0,1}. Here is a diagram demonstrating the results. Figure 1 - This is the result of the vex code written above (visualized left), notice when using the vex code normal the leaf is unable to correctly orient itself to the point (visualized right). The custom vex code normal is required to guide the orientation and the tree deforms. This is shown in the following .gif animation. Figure 2 - A .gif animation demonstrating the updating normal as the tree deforms I have also tried adding an @up vector to see if that resolves the issue, however, that route is also producing me undesirable results. I have though about using some form of quaternion or rotational matrix, however, I am currently studying these linear algebra concepts and I need time and guidance before fully understanding how to apply the knowledge in Houdini. Could someone please offer guidance in this regard. I am working on supplementary .hip file which should be posted shortly. Warm regards, Kimber
  3. FFX Align To Curve

    FFX Align To Curve HDA FFX Align To Curve brings a faster system for customizing orientation of geometry along the length of a curve. Working with point data directly, a user is easlily able to develop in realtime their desired orientation data. A clear adjustable guide system shows exactly which direction your geometry will orient towards once copied onto the processed points. Scaleable arrows reveal the primary tangentu orientation and travel direction along the curve. Auxillary normal and bitangent markers reveal the other axis orientations. Features include: - Guide scaling, opacity, and color. - Offset parameter to slide points along curve. - Reversible orientation direction - Roll, Pitch, and Yaw controls that can be varied over the length of curve. - Pscale (scale) point attribute that can be randomized and varied over the length of curve. - Cd (color) point attribute that can be varied over the length of curve. - Separate head and tail point breakout to allow for unique geometry from the main curve. - Plus other adjustment, and output options. Video Tutorial: https://vimeo.com/478682335 For more information please visit https://fendrafx.com
  4. I have some randomly rotated grids in 3d space that i'd like to orient to the origin on XZ plane (flat on the ground) and have the longest edge align with the Z axis. How can i figure out each grid's transform and orient and reset it. Controlling the way it gets oriented (longest edge) is important for UVing later
  5. Hello and welcome to this post. Synopsis: In nature, we see a phenomenon called tropism (the way a leaf orients itself towards the sun). I need help building a rig that will simulate this effect. These are the objectives: Create a source object acting as the reference point for tropism Get the leaf to orient itself in relation to the source Additional challenge: It would be ideal to shade the front and back face of the leaf with a different texture. What is a neat VOP setup which would simulate this? Here is a basic HIP file to begin messing around with. leafShading_Orient.hipnc
  6. i was trying to achieve this effect.. but the problem is how to get the consistent orientation of stars and other stuffs 98036676_290878841916233_2325447046790467126_n.mp4
  7. Initial particles orientation

    Is there a way to randomly orient particles on each frame? If I put down Attributerandomize node before DOPnet it gives me the same exact orientation every time particles are being emitted. I don't need that, I want completely random orientation for each particle on each frame. For some reason I can randomize color inside DOPnet but not orientation. What am i doing wrong? orient_particles.hipnc
  8. Hi folks, I'm stuck on a issue. I have a deformed geo that i have fractured in packed pieces. Then I want to use a popnetwork to drive my packed pieces. I would like to update the position and the rotation of my particles with the deformed geometry, but when i try to update the position with a pop wrangle like: @P = point(1, "P", @ptnum) with my geo source on the second input of the popnet, the orientation dosent fit of the original geo, the orientation is not updated. So, how can i update properly (position and orientation) of my packed pieces with the source deformed geo in the popnetwork frame by frame ? here is some video to show you, ths ! What i have, orient not updated: orient.mp4 What i would like, fine deformation: orientok.mp4
  9. 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
  10. Hey guys! I'm struggling a bit with a setup that's probably quite simple but I couldn't get behind it for a couple of days now. My shot requires me to have pieces which a character consists of (Megascan-assets scattered on a character) follow the character's animation. This looks something like this: walkcycle_fox.mp4 Now what I've tried to far was to go about the following with some fancy orientation math in a SOP-Solver in the dopnet to get the euler-W-acceleration to target the goal-orientation, but somehow the pivot offsets made this way harder than expected. My next approach (which I should have rolled with from the beginning) are constraints. So I'll try to have a soft constraint for each piece to a world anchor and target the rotation. But just how exactly does rotation-constraining work with the RBD-tools? I've found very little information on this topic - only for things that are individual objects, but not 800 pieces... I'm happy for any hint towrads a solution. Cheers, Martin
  11. RBD sim and orient

    Hello guys. Recently i have run into strange issue. I have my packed objects, that have some orient on it. I need to feed them into the Bullet sim, problem is that if i have orient as attribute on the packed objects, my sim explodes on first frame (no intersecting geo), if i remove my orient, sim behaves as expected. so i have run my sim without the orient coming to bullet (renamed orient to keep_orient) and i thought i will just substranct+add them at the end to get correct orient values for my instancing i do as next step. Problem i have is that i was not able to get correct orient from it. Would someone able to explain me what would be necessary to do to make it work, or why bullet explodes with orient values? sorry i cant share any scene at this point. my whole setup is: points in the space, that have @pscale and @orient (random nodes), that goes into the grain sim, to make sure i have no intersections, then i do copy bunch of rocks onto those points which goes as packed geo into the bullet sim.
  12. Hi everyone. I have a RBD sim that falling some geo's. And I wanted to copy some geo's to their centers. But theese geo's has no rotation data. How can I copy the rotation data of sim ? I tried to tranfer orient and w attributes and it doesnt work as well.
  13. Hey everyone, I'm looking for a little help on a pyro sim I'm doing. I've got a fuel and temperature source that move along a path, emitting flame. The goal is to make a look like the flame is propelling an object forward, like a jet engine. I'm able to achieve most of this easily enough, but my sim has a lot of wasted space because the sim container doesn't rotate with the movement of the source. This really slows everything down and it's driving me crazy. I've tried a few things that used to work in H16 (the "point position" node specifically), but H17 sources volumes differently and won't play nice (the sim will rotate the already rotated source volumes again). Most of this I learned here https://gumroad.com/l/TqUNR, which no longer works properly with H17's volume sourcing. Anyway, if anyone could help out with this it'd be great. inverse_transforms_6.hip
  14. I have a feeling this might be a dumb question, but I have been stuck on it for a few days now. Or maybe not so, as I've been looking countless treads here, but none really solved my problem. I've got a really simple setup, pop curve force guiding some rbd objects (I also tried doing it with points and copy stamping after sim to the same result). At a point in the sim the vectors start to point outwards: What I would need is for their direction to be always facing forward as they are at the start: I've had some luck with using pop torque, but still not what I need. I've attached an example file and the curve alembic. RBD_Directional_Vectors_Curve_Force.hip curve01.abc
  15. Hi, I'm facing a problem and I can't find a solution by myself so I'm asking for your help ! I want the object that come form the object merge (1) to be oriented relative to the normal from the pieces coming from the foreach (2). I hope I'm clear enough ! Thank you for your help !
  16. Hi guys, I'm very new to Houdini. I'm coming from a Softimage ICE background so my brain is still struggling with adapting to a new workflow so bear with me if you can! I was following this awesome tutorial from the Entagma guys (linked bwlow). In short, I replaced the spheres he uses at the end with the trusty ol' pig head and now I would like to figure out how to make these pigs heads turn in the direction they are moving as they slide around the surface. I've spend a long time googling and looking at previous posts related to particle orientation but I can't seem to find a way to adapt anything to this scenario. I'll attach the scene file if anyone has any advice? I think I would need to do something like finding the point position from the current and previous frames and subtract them to create the direction vector but I can't find a way to do that in any of the PopVops. I tried using a PopLookat and setting the target to look at the velocity but not luck. Any help would be appreciated. I'm not great at VEX, I come from ICE so Pop Vops etc work best in my brain if thats possible. Cheers (not sure how to reduce size of video in this post, apologies if it shows up giant!) Entagma_GrowthEvenOnSurface_V01a.hipnc
  17. Orient attribute

    Hello! I'm trying to create an @orient attribute on a simple circle (so the copies all point inwards towards the center of the circle) I laid down a polyframe & fed it's generated @N and @tangentu attributes into a quaternion VEX function but it's a no go. From what I gathered, I'm missing an "up" vector & a transform matrix & I'm not sure how to set this up with a wrangle... Orient_attribute.hipnc
  18. orientation not matching

    Hi guys. I have a simple sim with a tube which I steal the points from and want to instance another model onto those points. for some reason the orientation is not lining up. What am I overlooking here? shot_Coinery-Coinery_mod_Modeling_v0008_nocomment_jra_.hiplc
  19. Hi everyone, I would like to better understand matrices and how to use them to do what I want. I've prepared a hip file with screen shots of things I get and don't get. While writing this I'm almost making discoveries so please bare with me if it seems like a long thread First off, applying a matrix3 to rotate my points seems fine as long as my vector is normalized. Else, it affects scale as well. Why is that? 1. rotate around y matrix3 m = ident(); float angle = ch("angle") ; vector axis = {0, 1, 0} ; rotate(m, angle, axis); @P *= m; 2. rotate around {0,1,1}. Not good. matrix3 m = ident(); float angle = ch("angle") ; vector axis = {0, 1, 1} ; rotate(m, angle, axis); @P *= m; 3. rotate around normalize({0,1,1}) matrix3 m = ident(); float angle = ch("angle") ; vector axis = normalize({0, 1, 1}) ; rotate(m, angle, axis); @P *= m; Hence, we need to normalize the rotational axis vector to prevent scaling the geometry. Secondly, I'm having issues setting the pivot for my rotations. In the examples above this all works well if our pivot is set at the origin. So how do we set the pivot to be at the center if our geometry? Please take a look at rotate_not_at_origin object. To begin this little science experience, I've copy stamped boxes on a single box and used the normals from the orignal box as the rotation axis vector. So far so good. This all goes to shit if we move our original box from the origin. How do we solve this? The only way I've seen, and don't understand, is using @orient as follows before the copy stamp. Also, this no longer copies the geometry based on the normal direction of my points. matrix3 m = ident() ; float angle = ch("angle") ; vector axis = normalize(v@rot_axis); rotate(m, angle, axis); @orient = quaternion(m); So how do we solve this? I really need to wrap my head around this once and for all gahhhhh!! Thanks everyone! Maxime matrices.hipnc
  20. Polygon Jitter Orient Problem

    Hello everybody... I am working on a project and stuck on one point. Need a help so bad! lol In the hip file what i tried to do: Created a almost torus shape and and needed little bevel on the edges bla bla bla... In pointvop1 i am giving jitter animation to primitives and taking the animation from the sphere1's transforms. Through the animation, prmitives jittering/animating from object and they coming back to 0 poisition when sphere get far from the object. After that, in attribwrangle3 i am deleting primitives and using only points of primitive's center points. Ok here what i try to do! In attribvop6 i triend to use few attributes and the thing i need is. When points are far from the object i need to give them noise or turbulans or something that gives them motion and when pyramid shaped get close to zero position and create and object i need them not moving and just sit the 0 poition. In sum what i tried is they should rotate while they are going to 0 poisition and when they get close they should stop and just sit and stay. If you turn normal1's display flag you can see that they are not in real order. there are gaps and normals are not correct... I really stick in this part and cant move more. If any help would be amazing life saver lol Thank you for help! Lens_polygon_test.hip
  21. Hi everyone, I'm trying to do a school of fish with a particle system that would follow a curve. Basically I'm emitting some particles and they move along a curve with a popcurveforce. By default the particles orientation seem to go along with the curve but since I'm trying to do a school of fish, I would like my particles Z orientation to always be 0 so the fishes don't swim on the back. So far I've tried with this expression in a popwrangle : p@orient.z = 0; The thing is it seems to zero out the orientation of x and y as well.. And I still want the x and y to go along with the curve. I'v tried with a popattract instead of a popcurveforce and I'm still not able to constraint the Z orient.. Maybe it has to do with something else than the @orient attribute since I don't see it in my geometry spreadsheet..? There's something I don't get! (Needless to say that I'm new in Houdini :P) Thanks a lot! test_fish_school.hiplc
  22. Hello Guys, I have some issue with @orient values for particles on POP context after plugging POP torque / POP spin.When I plug one of this nodes my copied geo on particles start look like on ex_v01 gifBefore sim I randomize v@N for random look instanced geo after coping to points.When I bypass POP drag / torque all look fine randomized, because I think use Normal for adjust orientation, on randome direction gif you can see it.How I can randomize orientation value at the beginning of simulation particles?Thanks advance!
  23. Attribute Reorient Node Tutorial

    Hello community : i created this short tutorial on how to use the reorient attribute node in houdini and also i showed how it is work, it is some math matrix stuff, hope you find it helpful and hope you like it : Note : this training will give you nice idea of using the Matrix in Houdini , .
  24. I'm trying to mess around with orienting a particle's alignment to it's vector. Or a watered down version would be a cube on a path that follows it based on the particle's vector or velocity. Basically, orienting the particle to "speed space" if that makes sense? I tried mixing Normals and Velocity to possibly get them aligned but I'm pretty much lost. I took a look at @mestelahere to help me out, but I'm pretty much in over my head trying to do it in Houdini. I attached my file that is just a spinning circle with box's copied onto them. I was trying to make a simple scene where the boxes rotation matches it's vector. So nothing too out of the ordinary, but still kind of confusing. Thanks :)! velAlign.hipnc
  25. First of all, I want to tell you what end result I want so you can solve my scene file or suggest other easier way of doing it. I want to get the transformations of these rbd dominos to object level. My first approach was to simulate rbd fractured objects then use dynamics chop to get that data and export it to object level but it got some problems. My second approach was to "get point data" from dops and do some matrix magic in VOPSOP with points and import that data through geometry CHOP so it can get exported to object level grid's transformation. I have tried to use orient attribute to my advantage but objects behave weirdly. Their positions are wrong. This is good exercise for you to use SOPs, DOPs and CHOPs interconnectively. You can see my file with both approaches, check out these nodes and tell me what am I doing wrong? I just want to apply the boxes domino data to grids in object level. Thanks! dynamics orient.hip