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Found 67 results

  1. 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.
  2. what is a pscale attribute in houdini and how can we use it?
  3. 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.
  4. 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.
  5. 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?
  6. 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?
  7. 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
  8. 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
  9. 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
  10. 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.
  11. 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!
  12. 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!
  13. 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.
  14. 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.
  15. Hi, I was wondering, which pop attributes does the dop-pop solver uses to compute movement, also what's their mathematical relationship? I've got so far: v force targetv airresist the reason is that I'm not sure about the targetv-airresist force v interactions and I'd like to build a boids based crowd system and mix the use of pop fields and pop wrangles where I further manipulate v directly. Many thanks
  16. Hi all So I have a question about the new versions of the For-Each node, particularly the Numbers one, I have been following a tutorial from Anastasia Opera, and during the tutorial she uses a For-Each subnetwork node now I understand what this node is doing collecting the data from the box_id, Anastasia also gave the node a stamp name which will be used a bit later on for a blast node to specifically target some points following the local path hence why the stamp name was given to the For-Each Subnetwork node in order to lead a path towards a node that contains specific points with a number that is less than 3 which I understand is the point number and can also see it infant of me.... but now here is where I get confused in the new version of Houdini 17 the Subnetwork node has been disabled and be re-enabled but instead I would like to understand what on earth is up with the new For-Each Numbers node, it has some weird dodgy layout that just throughs me right off!! I would not mind trying to re-create the tutorial using this new node but its proving to be a challenge as I have no idea where to place the nodes that help in set things up for procedural modelling which I have tried to place things in myself but ended up with nothing but more errors. if someone could please help that would really awesome and I would really appreciate it. Kindly Ahmet .B
  17. Hi magicians, I was trying to create render passes for the fire, I want my temperature and fuel to be render as different render passes, I tried to use temperature and fuel as float in extra render images, but the problem is that, I am not been able to get it properly. what is the way to get render passes for temperature, fuel and heat in extra image details ? I would also like to know the way to render normal passes and any other passes which can be rendered out from volume, like opacity pass or something helpful in compositing. I get the fire mask from the shader but it is not that useful. Thank you.
  18. Copy Node

    Hi, I have a growing geometry, (via finding "neighbours" creating goup and than blast the geometry) and I want to copy/stamp objects to points of this growing mesh... But as it is growing the point numbers changing so the stamped scale/ rotation etc... is changing also... Any Idea for some solution or workaround? Thanks BK.
  19. Curves/Shape From Points Help

    Hey guys, so I'm taking some geo - - deleting away everything but the boundary points - in order to then create an edge using the ADD sop - take this and create polygons inbetween Currently I cant get the winding order/connecting order of my points right on more complex shapes with holes inside as such, heres my hip file any ideas or suggestions would be great! Thanks, C HoudiniHelpAddSop.hip
  20. Hello!! I am working in a triangulated sphere and I want to make the different triangles glow with different idensity according to their primitive attributes. Any ideas? thanks!
  21. It looks like it's possible to set point attributes all at once instead of looping through them one at a time. I was trying to do it with NumPy, but can't quite get it right. Seems to be problem with the custom attribute being an array. Given an array with the same shape,i.e., number of points x array size it looks like it should work, but doesn't. Incidentally, the NumPy array will contain data from a file. I can't tell there's a better way to pull file data straight into something like VEX, hence the NumPy array. Here's my test code: node = hou.pwd() g = node.geometry() pt0 = [1.0, 0.0, 0.0] point = g.createPoint() point.setPosition(pt0) pt_1 = [0.5, 0.5, -1.0] point_2 = g.createPoint() point_2.setPosition(pt_1) pt_2 = [1.5, -2.5, 0.0] point_3 = g.createPoint() point_3.setPosition(pt_2) g.addArrayAttrib(hou.attribType.Point, "MyFloats", hou.attribData.Float, 8) gp = g.points() # This works fine ''' gb0 = (0.5, 0.3, 0.1, 0.1, 0.6, 0.2, 0.3, 0.8) gp[0].setAttribValue("MyFloats", gb0) gb1 = (0.2, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1) gp[1].setAttribValue("MyFloats", gb1) gb2 = (0.7, 0.6, 0.1, 0.5, 0.1, 0.2, 0.8, 0.9) gp[2].setAttribValue("MyFloats", gb2) ''' import numpy as np y = np.arange(24, dtype=np.float32).reshape(3,8) g.setPointFloatAttribValues("MyFloats", y) # error print g.pointFloatAttribValues("MyFloats") # error
  22. I hope the title is clear enough, essentially what I am trying to do is create a custom image plane that will output an rgb matte for objects being refracted by another object. (in my case objects inside a glass sphere) lets say i give an object inside the glass sphere a vector attribute of green {0,1,0} is it possible to output an image plane that displays that attribute through the refraction of the outer sphere? I've been searching for a while all over google and OD but have yet to find exactly what I'm after.. I feel like Trace() is about the closest thing I could find, but not sure how that would work for what I'm trying to accomplish.. Perhaps my approach is wrong as well, if anyone knows hows to accomplish something like this, I'm all ears. Ideally I'd like to accomplish this with image planes if possible and avoid having to create separate takes and what not.. Thanks!, -C
  23. Access "dead" attribute in a point

    I was reading some comments on how the @dead attribute generated by particle streams changes to 1 in the subframe before being reaped by the solver. Is there anyway to access this attribute after the simulation? For example, if I wanted to create a static point in that same position as the particle that is going to die? By the way, the generated particles are not from a POP Network, but yes from a FLIP simulation.
  24. As I can understand from the Houdini documentation, the "@opinputn_name" will access attributes from the secondary inputs. I am trying to access the "numpt" by "int numLastPoint = i@opinput1_numpt;" but this does not work. Im I missing something?
  25. Help with the Cube Man

    Hey Guys, I am working on making a character out of cubes. Basically I want to be able to have the cubes on the mesh, conform to the topology and then have the control to be able to move, rotate and scale the cubes independantly while still conforming to the mesh. I have been looking around and found some good solutions for this (see attached images 1 and 2) and I feel that I am close but I have been running into a few snags that seem to be a bit above my level of expertise and was hoping to get some assistance. As you can see in image1 the rotations seem to tear or collapse into the cubes as opposed to rotating on a local axis from where it is placed. Basically after calls to primuv and prim_normal any calls to rotate or scale points don't seem to apply the way they should or how you would expect them to. (I hope that makes sense.). If you guys see or know of a better way to implement this type of solution then I would be more than happy to listen and learn. Thanks for your time. Cheers, Christian
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