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Found 78 results

  1. Hi, I'm having some trouble getting the 'Vorticity' attribute to show up in my cached sim: I've already made sure to check the 'Keep Attributes' for the fluidcompress node with 'vorticity' previously also checked 'Transfer Attributes' with 'vorticity' Also tried recaching everything again, but it still doesn't show up. Will appreciate any help I can get, thanks!
  2. Happy Friday, I'm currently working on a project where I need to export alembics assets into C4D. The assets I want to export have embedded Prim attributes that I want to convert to Prim groups in order for the artist to have control of the material selections in C4D. Currently, I'm splitting all the attributes and converting them to groups manually which is time-consuming and can break. Since I'll be modifying and making adjustments I was wondering if there was a more procedural way of doing this through a wrangle or possibly the partition sop? Any help would be greatly appreciated, thanks!
  3. 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
  4. Hi everyone, I'm currently trying to fit as many bounding boxes (from buildings) onto city blocks as possible. As the way described (I followed a tutorial on pluralsight) didn't provide me with the result I wanted (more tightly packed city blocks) I tried to combine other methods with it. The most promising approach seemed to be using the UV Layout node to pack as many bounding boxes onto the city block as possible and in later stages of the process "pull them to the streets" and save out the points of the bounding boxes, replacing them with the actual building geometry. The problem I'm now facing is the following: While the UV Layout SOP rotates, packs and prepares my bounding boxes fine on the city blocks, it doesn't affect the normals of the primitives I want to be packed. I'm giving them a normal of 1|0|0 and even though they are clearly rotated, the normal still points into the same direction. This results in a wrong rotation when I'm later copying the real buildings onto the points as only the changed rotation by the sim that pulls them to the streetside is applied to the normal. The rotation that was already there by the UV Layout SOP gets lost. The question now would be: Is there a way to somehow access the rotation of the primitives that gets applied via the UV Layout SOP? If no, does anyone have another idea how to rather tightly pack the cityblocks with geometry ? I can't seem to find another solution for geometry packing onto surfaces really. Any help would be greatly appreciated! Cheers Daniel
  5. Hey, Trying to workout a good asset workflow coming from Maya to Houdini. Geometry wise we are using Alembic and I'd like to add an attribute in Maya (or similar method) to define what materials are assigned to what geometry (shape assignment, never face assignment). Then in houdini use that attribute to assign materials to the alembic cache. So far I've managed to add a string attr to the shape nodes in Maya and export that into houdini fine. Once the alembic is unpacked I can see the attributes there. I cant seem to get those prim attributes to be used in the material node downstream though, as you could do with groups for instance. Any tips would be much appreciated, or other workflows that could be better. Cheers
  6. Denoting an attribute as "Tex"

    I have been needing to make some custom utility UV sets for use in things like Unreal nDisplay and other technical usages of texture coordinates. I am using some atypical techniques to create and convert P and other attributes from second inputs on attribute wrangles and such, all is fine for this, but viewing the UVs has been tricky. What I'm wondering is if there is a way to get a vector attribute to be "tagged" with the Tex "sub-type" so that it is available in the UV Viewport auto attribute list. For now I've had to always create my UV attributes with a UV Texture SOP and then set those attributes to my results in a wrangle so that they maintain this mysterious (Tex) signifier you can see when getting info on a node next to the attribute ( for example : "uv0 3flt(Tex)" ). I'm just wondering if there's a way to add this "tag" to an attribute down the pipe instead of via a UV SOP that initializes the attribute, thus making it appear in my list of uv attributes in the UV Viewport. I can't discern an option for this in attribute create or otherwise, nor can i find an official name for this attribute "tag" or "sub-type", anyone know? Thanks! P
  7. Hi everyone, I'm walking around the whitewater system. I watched the whitewater masterclass with Omar Zarifi, and near at the end he uses an attribute called @pbfstiffness, and it's really cool. I'm wondering if there's any more attributes like that which can be used for greater control. Is there any list out there about the available attributes especially in the whitewater environment?
  8. Hello! I am trying to make use of the Lightmap Resolution_Attribute which can control the size of lightmaps in Houdini. (more info on these attribures... https://www.sidefx.com/docs/unreal/_attributes.html ) No matter what i try, the attribute "unreal_lightmap_resolution" gets not picked up in unreal. At the same time, the attribute "unreal_bake_name" works fine... Someone already asked the same thing a few months ago on the sidefx forums, but no one had a solution. https://www.sidefx.com/forum/topic/69608/?page=1#post-295760 Any ideas welcome! Thx Felix
  9. Hi, Im trying to create different overrides for diferent arnold render_out nodes, like takes, or like the render setup in Maya, I know I can use the option of use phantom object or matte in the arnold_out node, but is more powerfull to use overrides, it give us the possibility to override more properties like cast shadows, recieve shadows...etc (I dont know this names exactly right now). The thing is I go to out, and I create a node Set_parameter (arnold node) and I conect this to an Arnold_OUT, in the Set_Parameter I create the path for the section I want to override, in this case is an geometry node (selection: obj/geo1/*) inside for example I put a box for testing, and next I write the attribute I want to override, in this case I want to override the arnold parameter from geometry, in this case I write...for example... subdiv_type = "catclarck" subdiv_iterations = 3 ok, this two parameter are working for me, when I activate that arnold rendere node to render, that parameter change and I can watch it in the render, even also work for me this parameter override: matte = True but, and here is my problem, I really want to override the visibility tab arnold parameter, like visibility rays to camera, self shadows an so on...but I cant it work, in this case I write... visibility_camera = False and this last one no work for me, how can I do for this work??? (visibility_camera for example), I only go to the parameter in geometry, arnold, visibility tab and I let the mouse over the parameter, and in the floating window I can watch the parameter, in this case is ar_visibility_camera but I thing for use this attribute we have to remove the ar_ , but event with this I cant get the override for visibility. I let here the official Arnold web site with Set parameter info... https://docs.arnoldrenderer.com/display/A5AFHUG/Set+Parameter Thanks.
  10. Alembic particles to C4D

    I spent a fair bit of time trying to figure this out today so I figured I'd post a quick tutorial for posterity. The only other guides and info I could find were specific to getting pscale and Cd into C4d for Redshift. Nothing on orientation or other attributes generally. Long story short: - Unless your attribute is explicitly typed (i.e. Vector, Quaternion, Matrix instead of 3flt, 4flt, 9flt) C4d will read it as a float (or "Real") - Orientation is handled by the "Alignment" TP channel, so you need to convert your @orient to a matrix3 before export Hope this saves someone else some time.
  11. Hello; I'm looking for some good tips or tutorials about how to use "attributes" tab in the "Soft Transform" SOP? Thanks for helping.
  12. Hello peeps, I'm trying to do something relatively simple and I think this was asked before but so far I couldn't find the right answer or the right video with that info, so far. Somewhat easy question.... I have a custom point attribute created with a value @Cd from an "attribute from map" node placed up in the stream and I want to use this custom attribute to control a parameter, in this case "scale.y" of a geo copied on points. I remember watching one of Jeff Wagner's class sometime ago where he talks about attributes, attribute transfer and using attribute as parameter and on the ladder, he calls a custom attribute on a parameter by typing the custom attribute name in the parameter field, something like "@customattrib > 0.3" or something similar to this. Curiously, I remember thinking that that trick was neat because he didn't use the famous point() or detail() expressions in the parameter field to call the custom attribute inside the parameter. Very efficient way to use custom attributes...That said, does anyone knows the video where he talks about this or knows that correct syntax to call the custom attribute in the parameter field without using the point or detail expressions? Any help is greatly appreciated.
  13. what is a pscale attribute in houdini and how can we use it?
  14. Hello everyone. I have a long sequence where changes happen in the geometry, I have an attribute that changes to 1 whenever the geometry change happens. I would like to store which frames the attribute jumps to 1 in something like an array, does anyone know whether this is possible in VEX? and if so how? I hope I am clear enough in what I want.
  15. Hello, newbie here. I'm following an old tutorial and in order to delete closed/un-closed primitives the guy created an attribute called "closed" which is then referenced in a delete node. He uses $CLOSED in the delete node but when I do the same it shows it as an error. Is this a deprecated way of calling the attribute? I tried @CLOSED instead and that seamed to work but I have troubles further down the line and I'm trying to figure out if this makes a difference.
  16. how get attributes name?

    Hi odforce, i have a small problem,its confused me a few days.how can i get the attributes name use vex or python(vex is better,because im not familiar with python)? for example,i have a geometry with some point attirbutes like "v" "Cd" "mass" "aaa",and prim attributes like "prima" "primb".if i want create a new string attribute and store all the attributes,how do i achieve that?
  17. Hello, I can't figure out how can I reference houdini attributes in the octane network material. I see there are two nodes called "Color Vertex Attribute" and "Float Vertex Attribute" but I don't know how to use them or reference the attribute I want. I can't find anything about them in the documentation either. Does anyone know how to do this?
  18. Why is my Color Transfer Offset?

    Hi Guys, Im trying to achieve this stepped layering effect on my mesh and figured the correct approach woould be to use a shatter boolean with multiple cubes (which i have colored differently) and then transfer my Cd attributes across however although i am getting the hoirzontal cuts across my mesh in the correct place as intended, the color transfer is offset (almost as if my exactly half of the original cubes height) Why is this occuring / how can i make sure the color transfer occurs only between the cut lines ? Thank you
  19. Houdini Tutorial Monument Construction Time-Lapse Download Houdini Project File - https://gum.co/timlapse Available for free: https://www.youtube.com/playlist?list=PLtCPgCB2Kw05gvrIR3CPCe8VhzCzl2HBd&fbclid=IwAR137yDe7ftp_aQtK3LoOCODQKVaJLa6d9AP7_wDjVVDAR1rDmLAUirto3k - Chapter 1 Dividing Geometry Into Bloks - Chapter 2 Gradual Emergence of Pieces - Chapter 3 Procedural Animation of The Crane - Chapter 4 Modeling The Crane - Chapter 5 Metal Scaffolding Download Houdini Project File - https://gum.co/timlapse Explore my products: https://gumroad.com/rart Follow me for updates on what I am creating: - Artstation https://www.artstation.com/raducius - YouTube https://www.youtube.com/channel/UC1Avewug9ZPCLx1URXVEw4g - Instagram https://www.instagram.com/raducius
  20. Hi, How can I get Start and End point positions from the "Find Shortest Path" node? I need these to be a point attributes to export them into Unity Point Cache format. Or another example, if I have a wireframe cube, Houdini drawing these edges of a cube, so it definitely knows all the start and end point for each line, so how can I get this data about Start and End points for cube edges? Here is the project file: Veins01.hip
  21. Hi, I am trying to make a wall generator. A wall is divided into segments and each segment has a @windowType attribute which decides what type of window will be displayed on the wallsegment. The user interface will work as follows. The user has access to 2 sliders: one to select a wallsegment on which the changes will apply and a 'select new type of window' - slider, which allows the user to pick out of 5 presets. The chosen preset will be displayed on the wallsegment. The way I got this to work was by declaring an if-statement stating: if(wallselected == @primnum) { @windowpreset = chi('selectNewTypeOfWindow)'; } This works. But a problem occurs. When I want to select another wallsegment that I want to change, the new preset jumps to the newly selected wallsegment, which means that the previous wallsegment (it's @windowType attribute that is) remains unchanged compared to before. Is there a way to make sure that the preset of a wallsegment remains changed, even when the if-statement isn't applicable anymore? I hope this is somewhat understandable. Thank you for looking into this.
  22. I have an attribute wrangle SOP running over points, in which I need to read the value of a detail attribute for every point. This seems fairly straightforward using the supplied attribute functions, but I can't get the behavior I need. Below is a simplified version of my VEX code, with calls to printf for testing. The geometry it's running over has an integer detail attribute called "last_clean." printf( "last_clean=%d\n", int(detail( 0, "last_clean"))); printf( "ptnum=%d\n", @ptnum ); if( detail( 0, "last_clean" ) == @ptnum ){ printf( "test\n"); //do stuff in this loop } and here's the output: last_clean=0 ptnum=1 ptnum=2 ptnum=3 ptnum=4 ptnum=5 ptnum=6 ptnum=7 ptnum=8 ptnum=9 ptnum=10 Note the lack of "ptnum=0" or "test." The only rationale I can imagine for this is that the call to detail() turns the wrangle into a detail one for that iteration, thus making all references to @ptnnum basically meaningless (which still doesn't exactly explain why it only reads the detail attribute once). But I can't find anything in the documentation about this behavior of those functions or wrangles (what else is new...). Can this behavior be changed? Is there a stupid error I'm missing? The wrangle is in an orange for loop block if that's relevant. Thanks for your help!
  23. Hey magicians, I'm playing with vellum and pressure, and I want to have more control by using color to control attributes. Lets say I have in red the zone I want to get "stretchstifness", my process was: Color with attribute transfer Attribute create "stretchstiffness" with value $CR Point vop > bind import "stretchstifness" > fit range > bind export Plug that into vellum but doesn't seem to work, also, what if I have several constraints (like cloth, pressure) how can I tell that the "stretchstiffness" is the one in Cloth and not pressure? Lastly, inside "Vellumsolver" I have vellumconstraintproperty with animated restlenght in group @type=pressure to make the stuff inflate, how can I make the red color control the "restlength" attribute that is inside Vellumsolver? Thanks!
  24. I am trying to get the value of a string attribute, but it returns "0". I then noticed in the node info window that it was marked with "(4 unique)" What is this "unique"? how to handle it? I am just trying to get the string value that is represented in the spreadsheet.
  25. Hi, Could somebody please explain, on http://www.tokeru.com/cgwiki/index.php?title=HoudiniVex I can't understand the reason behind "It's worth pointing out that if you're defining the groups yourself, you're better off using an attribute to identify the pieces, and use that to do your random whatevers." I mean, I don't understand are there any advantages in deleting(for example) some points/primitives by using additional attribute over deleting them by @ptnum/@primnum. Thanks in advance.