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Found 23 results

  1. Ugly artefacts

    Hey, got a pretty annoying problem. A certain area of my ocean always gets some artefacts. The dark area isn't responding to AA blur, geometry input etc. Rght behind that its okay again. ANY idea whats the problem here?
  2. Instance Time offset

    If someone would help me with this I would greatly appreciate it: 1. I have a SOP with animation on it. 2. It is instanced via the point instance technique Question: How would I offset and randomize the animation timing on each instance? Copy sop is too memory intensive and the geometry is heavy as it is.
  3. Hello all, I'm having trouble recreating this image... I'v made a sphere have tried to slice it in vdb's but cannot figure out how to achieve the shape? If anyone could point me in the right direction it would be much appreciated! thanks,
  4. Instance Pack Trouble

    Hi guys , Based on the tutorial Applied Houdini - Rigids II Structure Destruction I'm try same effect , But i have trouble is instance pack , i m use same techniques in this scenes . But i don't know why matrix replace does not work . Hope your help .Thx every body. Please find attached for details
  5. Is it posable to transfer the @Cd attribute to geometry with the instance sop? With the copy sop you can Use "Template Point Attributes". The instance sop has no such option. The instance object picks up a @psclale attrib but not a @Cd attrib? Thanks
  6. I have a question that has been bugging me for some time and I couldn't find much information about it. Which is the best and most efficient way to render many polygons? Using delayed load procedurals or using packed disk primitives? Or, am I confused and are they both doing the same thing and there's no difference between the 2 workflows? As far as I know, they both create instance geometry. The documentation doesn't help much either, half of the things I read talk bout optimizing a render using delayed load procedurals, and the other half about using packed primitives. I'm wondering if packed primitives is the new workflow and using delayed load procedurals was the old way of doing it as is now obsolete? Here are the 2 workflows I'm talking about: Packed Disk Primitives Here I pack all my geometry and write it out to disk. I then load it back and change the load setting to "Packed Disk Primitives". Then I generate my IFDs and they are now referencing the geometry from disk instead of having to write them out (And the IFDs are a few KB or MB big). I then render using those IFDs. Here is what the documentation says about it: "Packed Primitives express a procedure to generate geometry at render time." "Because Packed Disk Primitives by their nature are geometry streamed from a file, similar to Alembic primitives, we don’t have to use a special procedural to get smaller IFDs." Delayed Load Procedurals Here I write out my geometry (not packed) as bgeo and then make a Delayed Load Procedural shader and select the bgeo files I just wrote to disk. I then go to the Rendering -> Geometry tab of my object and load my Procedural Shader. I then create my IFDs and then render them out. In the documentation about the delayed load procedurals, it talks about optimizing geometry this way. So I know there are these 2 ways, but are they both equally the same, or is one of them better than the other? Which workflow do you use? Also, when using the packed disk primitives, if the geometry you want to render is unique and it can't be instanced (or there's just no point in doing it), do you still pack it (so its only 1 packed prim) and save it out? Or do you use the delayed load procedurals? Do you use any other workflow? Any advice on this would be greatly appreciated! Thanks
  7. Hello, I'm instancing a geo on a set of particles, but I need this geo to have an animation under certain conditions. I've search for ways to instance (or copy) animated geo, but all I found is how to offset an animation randomly. What I need (see attached .hip) is to either start an animation when a particle reach its destination (there's a popseek) or even better, to control an attribute that drives the animation (that would be the "Up" slider I made on the "geo2instance" node, at the scene level) I'm a little confused over a few points: - Should I instance (as in the attached .hip) or should I use a copySOP ? - The animation I need is really simple, it's just the size in Yaxis of a box. Do I need to animate it, and then control when to start the animation ? Or can I drive the parameter later on, after copying/instancing over the particles, using condition like if velocity is lower then this, or if the distance between that particle and it's goal is lower then this ... Just to be clear, I'm trying to have this : when the particle reach it's goal, then the central box should rise up. thanks guys ! OD-F_instances-animCTRL.hipnc
  8. Hi all, I just cant seem to find a working method...so help please. I got animated alembic geo coming from Maya and I need to instance it on bunch of points with some random time offset. My original plan was to create attribute named tShift on instance points and somehow call it on geometry to instance like timeshift node $F+$tShift ...but thats not working. I was hopping I could get same thing as copy sop but with instancer...its another bird semi flocking thingy and Im stuck..... All ideas and help are very welcome! K.
  9. pre random rotation then orient.. hi!Some questions,just can`t get this effect in instance!could anyone help~!thx! rotate_in_copy_H15.hip
  10. Hi guys. I want to create an asset for copystamping which will allow to connect or disconnect SOP inputs. Would be nice if asset allow to use different input numbers of instance at a time (connect/disconnect necessary objects) and switch between instances. I can manually create a CopyStamping asset if I have a static number of inputs and if I know a number of input objects which switch operator will use (basic copystamping technic). I've dug out some info and looks like it's best way to create the asset with a callback scripts. But I'm not familiar with callback scripts and python enough. May be some body can help me with that or have a links for similar solution. Thank you.
  11. Hi everyone, I apologize if this has already been asked but i couldn't find an answer for this precise case. I have points with a bunch of attributes and I'm using an Instance Node to render them. Each instances is set by an instancefile attribute. I want to use the id attributes to export aovs from the shader but I can't find a way to have the instances inheriting the points attributes. You can see in the example file what I wish to do with the instance display node unpacked. I saw post about the function instancepoint() applied to the object to instance but I guess that in my case I cannot use this with instancefile since files are written ahead. Maybe should I find an other way to instance my geometries which are currently in files debris.0001-0050.bgeo.sc using the attributes pieceNbToInstance to somehow filter the piece to import but ideally I'd like to use the easiest way if possible so I don't write unneeded stuff in the IFds. Any ideas ? Thanks ! Chris instancefileWithAovsUsingAttributes.v1.hipnc
  12. Hi, I am relatively new at Houdini and I am sure I am making a few things quite inefficiently. But this is one I am pretty sure I must be doing it quite terribly so: Basically I am doing a small flock simulation from scratch (which my producer gave me a whole day and a half to do, ) with a animated loop for the bird instance (wich I also had to do on the same day an a half). Now, when using instances the animation works super fast, but once I offset the loop with a copy stamp technique on a time blend everything becomes quite slow....understandably. The technique I got it from Peter Quint tutorial here: https://vimeo.com/24969874 And it is quite useful (thanks Peter) but it is 5 years old! I wonder if nothing has changed since then. Because as I said is amazing how fast using instances Houdini is but as soon as I use the copy stamp technique, not so. And I have 200 birds only.... i cannot imagine the cost if it is 5000 particles.
  13. I would like to know what I am doing wrong here. Stamp random objects to grid points works fine, but not on particles. Please have a look and let me know. rand_Instance.hipnc
  14. hey, the question is what the topic says. this bugs me since I have started using Houdini. so far nobody was able to show me that it is possible or tell me that it is not, for sure. So is it possible to object merge instance object? I know some workarounds but I'm curious if I can do this. thanks for the help! D.
  15. Hi, guys. I'm working with instance recently. Let's say i stuck on something like instance with normal problem. There was a example i built: i have a mountain sphere with point normal, i will show the N pass, then i instance the smalll ball on it, then tranfer normal to small ball. if i just use copy sop, it works correct. The N pass show right color. After that i try instance sop, it was great tool. I override the material N, it link to the sphere point normal,. It seems working, but was a wrong way. The N pass show a different color. I have try my best to achieve it and keep modify the material again. But if anyone can help me out it will be great! Thanks. surface_normal copy_correct_normal instance_normal instance_with_normal.hip
  16. Hello! I am currently trying to wrap my head around being able to transform (rotate) instance objects for sop copy and instance rendering. Basic stuff, I know, but I'm stuck and my math suck. I have a hard time grasping dot product, cross product, matrices and quaternions -> 3D transforms There are, as far as I can see, a multitude of attributes and options to do this, and I am wondering what would be best suited for my use? Some use up, some use orient. Basically, I would like to have the rotation options of the transform sop (x, y, z rotate) to work on a point instance where the normal direction is the "up" direction (think teapots standing on a displaced ground plane, rotating planar to the ground when editing the y axis). I've been through a lot of examples but I just can't make them work for my scene. Either the objects are flipped or rotation is happening on the wrong axis or objects are not rotating smoothly, or I am not able to figure out how to "flip" to the right axis when using N and up (usually +-90 degrees in x) inside the vop. Most of all, it needs to be stable on deforming geometry. Any example of rotation working in this scenario would be most welcome! Also, if you have a link to a good (basic level) resource regarding this topic, that would be awesome! Thanks.
  17. Hi everyone. I try to do some kind of flocking bird effects where al the birds are offset in animation with instance objects. Now i have setup a simple scene with just some tubes with a sin expression on the translate Y which i want to offset using chops.just for testing but i cant figure out what i do wrong. I think its a simple fix but i dont have that much of an experience with chops. anyone? thnx alot ChopHelp.hip
  18. seeing the last particle tutorial on sidefx using H13 plus the halloween instancing tutorial instancing seems to work a bit different on particles i think. Im trying to randomize the color of the green channel of all instance particle models. On the (auto created) location_particle Object node - I added a instance node and after that - a material node. -overrides material use local variables ON -baseColor and as a color: rand($PT) does anyone know how to randomize the color? thnx
  19. Hi there! Could anyone show how to use the brand new feature "Share Displacement Between Instances" ( vm_sharedisplace )? I've tried to see the difference on performance or memory usage with that property and without it. But didn't notice any profit Maybe my scene is not very representative and I can't notice anything on such a simple setup. I have Fast Point Instanced 15k primitive Alembic delayed load on the 64 point grid. With that vm_sharedisplace property ON I just see that there are no more Creating displaced geometry (/obj/sphere:/obj/instance1: ) lines in the output for every instance generated. I'm turning it on the /obj/instance object itself. Displacement is in the uv space. Is anyone using this feature? instance_displace_06.hip
  20. I can't find the reason why my instanced boxes are offseted from the particle position .... Can anyone help? Thanks in advance! Offseted Instances 1.hipnc
  21. greetings all, I am instancing some geo which has shop_material_path primitive attributes baked into it. How do i get Mantra to read these from the geo and ignore the fact that the instance points do not have this attribute? In other cases we have used ids to drive a switch in a massive multi-shader but this is very laborious to manage any ideas would be greatly appreciated! please find attached an example hip cheers rnd_sam_shaderTest_v001_sam_forSESI.hip
  22. Can I do some thing like this in Houdini? So many instances (bullet casings) without actually using RBD! He approximates the volume of the casing with two particles so to get the orientation but he doesn't go in to much detail.. I am trying to do a tire spinning over many gravels. I used the RBD Point Object but the performace is very low when I use a lot of instances... How do you approach a scene with such a high count of dynamic objects ? scene files: http://area.autodesk...4UnfoldDemo.zip
  23. Is there any existing functions for extracting the final Transformation matrix that used for a copy or an instance. I am aware of the rules that create it : http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=6679 but are there any existing python functions (or easy methods) that allow you to extract this transformation matrix from a hou.Point() Object ? Thanks in advance,