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Found 28 results

1. ## Create new prims from points

Hi, I'm trying to solve an interesting task in Houdini while I learn more about VEX and just ran into a situation where I'm not finding an answer anywhere. So, I created a voronoi sphere and then added center points on each "piece" (face) of the voronoi cells. What i'm trying to do next is to create new primitives using each center point created on the previous step. I figured out how to do that by manually adding each vertex in the code using the addvertex function but it would be a time consuming task and it would kill the procedural process. Also, I noticed that as I start creating each face by entering the center point numbers on the code, some point numbers get shuffled resulting in a wrong face sequence and winding. Attached are some images showing what I got resolved so far. That said, how can I create new primitives using the voronoi center points? I tried sorting the point order and then creating a primid that could later be used in the add sop to create new prims but because there was no primitive connecting the new center points, the resulting primid was -1. Just for reference, I tried using this code and it resulted in the negative primid: int ptorder[] = primpoints(0, @ptnum); i@sort = find(ptorder, @ptnum); i@primid = @primnum I see that there are potential functions that could help in this case like nearpoints but i'm not sure how to sort the points correctly so each primitive could be created correctly or if it even helps. Any thoughts on this would be appreciated.
2. ## removepoint problem

I have a resampled line and I'm gonna delete some points on that, why removepoint does not remove primitive anymore in houdini 19?
3. ## PYTHON - Access primitive attribute on newly created node

i am using python to create a file SOP assign a path and import a bgeo file. After that i am creating some more nodes in my graph and i need a primitive name attribute from that bgeo. From primitive 0 prim = filenode.prim(0) #get first primitive of node filenode name = prim.attribValue("name") #get primitive attribute name This throws an error ----> AttributeError: 'SopNode' object has no attribute 'prim' Is it possible to read the attribute?
4. ## Custom parameters

I've been told how to create a primitive in a previous post. Creating a primitive - General Houdini Questions - od|forum (odforce.net) Now I want to know if I can set up custom parameters for my primitive? I want it to have similar parameters that the scales in the video below have. 08_RepTile_Scale_Test_01_InitialTest.mp4
5. ## Creating a primitive

How can I create a primitive in Houdini? This is a cylinder in Maya and I want to create a primitive just like that with parameters.
6. ## Add primitive in VOP

does anyone know how the add primitive workflow is inside the attribueVOP?
7. ## Is it possible to create a new prim intrinsic?

I very much enjoy the convenience of the "Alembic Group" node and would like to bring that to an FBX (File node) pipeline. Alembic Group's hierarchy selection seems to be based on a writeable string primitive intrinsic called "abcobjectpath." When importing an FBX using a File node, it comes with path attributes that can be used with Alembic Group but ONLY if I can somehow copy them as a prim intrinsic called "abcobjectpath." Is there any way of creating an arbitrary prim intrinsic out of nothing?
8. ## Primitive Center Rotate in VEX

Thought I'd share a little primitive center rotation snippet, any comments welcome. Note: Requires connectivity node upstream set to primitive and attrib "class". //Rotate primitive around center and defined axis int points[] = primpoints(0, @primnum); vector axis = set(0,1,0); //define user axis //vector axis = normalize(@N); //if normal axis is required float angle = ch('angle'); matrix3 rotm = ident(); rotate(rotm, radians(angle), axis); //get center (requires connectivity node, set primitime and sttrib "class") string grp = '\@class='+itoa(i@class); vector CenterPivot = getbbox_center(0,grp); vector pos; // move points to origin, rotate, move back foreach(int pt; points) { pos = point(0,"P",pt); pos -= CenterPivot; pos *= rotm; pos += CenterPivot; setpointattrib(0,"P",pt,pos, "set"); }
9. ## Get polygon and normals in Python

Hey all- I have a simulation running that is controlling the position and orientation of a grid that comprises just a single square polygon. Trying to use python to output the normal and center point of that grid. I can access the first hou.Prim, but I can't figure out how to get the polygon to get the normal. How do I do that? Thanks! Dave
10. ## process on unpacking point primitives after a RBD sim ?

Hello I'm doing a RBD (bullet) sim with custom concave geo (proxies) that I pack my self using assemble. I use a scatter and copy to points to set up my inital state, run the sim. I use a dopimport, and I would like to fetch the hi rez geo. Tutorials show that if I had the high rez geo scattered the same way I could plug it and it would work straight away. However I would like, with only my points, to retrieve the high rez geo. I thought I would use a foreach and apply primintrinsics or transformpieces or even a copytopoints as seen in some tutorials like here but nothign works, my scales and pivots don't seem to work. To give you an idea of what my network looks like before the dopnet: I cross posted on Sidefx forums but it wasn't published sorry for the crosspost. If you have any info on this I'm very interested.
11. ## Mesh from Lines (leaf)

Sup guys, What would be the best way to create a mesh from these lines? Scene file attached Leaf_v0102.hip
12. ## for each named primitive_problem

i am trying to run over named primitives, but the for each loop seems to pick randomly for each iteration which batch to process. i want the loop to respect the sorted primitives and run over each named primitive as it is in the geometry spreadsheet. How does it pick the first batch for iteration number 0? can i change that? image 1 is before the loop,sorted primitives image 2 is inside the loop with a single pass to see iteration 0 As you can see the first batch the loop chooses to process is not the first batch as sorted before. First batch should be the one named color_229_229_0
13. ## making primitive from closed curve.

Hi, I'm Edmund and I'm beginner on Houdini. I'm trying to procedural road and block for city. Is there any way to making primitive by using closed curve or something?(attached)
14. ## Find Intersecting Packed Primitives with a geometry

Hi there, Lets say we have a bunch of packed primitives scattered in an area on the left side and a on the right side a geometry, like frustum. I want to detect all the packed primitives that even a small portion of their bounding box is intersecting with the geometry. I have one method of doing this but its not ideal, I was wondering if anyone knows an efficient and preferably with vex way to do this. Cheers, C
15. ## pivot Edit pivot to match a primitive/normal

Hi guys, how can I edit the pivot to match a specific surface primitive or normal? I need to transform the arm of my robot in a specific way, so my pivot needs to be edited to match the surface normal. I already tried to edit it with " and ' but this only allows to move it but not to rotate it :/ Roboter.hiplc
16. ## where does houdini stores the transform info after the animated mesh is packed

Hi all Im having a big confusion about packed primitive. Lets say I have an animated and packed sphere. when I check in primitive intrinsic It is having the packfulltransform info, But if I convert it to polygons and pack it again then the packfulltransform info gets ident matrix and no animating values but still the mesh is animating. My question is where does houdini stores the transform info after the animated mesh is packed. I hope it is some what clear. packFullTransform.hip
17. ## RBD Objects struggling to interact

I have three individual components to this briefcase, the body, the handle rings and the handle, the body is a static objects and the other two are RBD packed objects, all concave. I am trying to get the handle to hang from the suitcase naturally but they are falling through each other, there is a slight reaction but i cant get them to completely react to each other. I have attached a zip of the three .obj files and the .hip file if anybody could have a look. Any help would be really appreciated ! Thanks! Assets.zip
18. ## Packed disk primitive, relative material assignment

Hello, I am trying to assign a material to packed disk primitive. This was already asked here many times but still I am not sure about my current situation I have geometry with two groups, I want to assign two materials based on those groups. However geometry is quite heavy so it makes sense to load it as packed disk primitive so that viewport is fast and ifd small. This geo is part of a digital asset, digital asset contains shop network with those shaders. So I need a way to assign material using relative path. I tried it but unfortunately it doesn't seem to work. With absolute path it works as expected. I also do not want to unpack the geo inside asset, because then I would loose packed disk prim advantages. One solution would be to save it with absolute path and put shaders always inside /shop/... But if I could make relative material path assignment working, it would make my scenes cleaner as everything related to the asset is included inside the digital asset. Thanks, Juraj
19. ## How can I do to reduce render time in growth animation using polywire

Hi guys, I'm now working on a work kind of growth animation.. and I've faced a problem that it takes tooooo long time when render or even import, since what I want to make is the extremely dense object wrapped with polywire like second image or even more than. In my setup, I made particle trails and applied them to polywire to make mesh. As you know, like the attached image, the denser(the higher frame like a second image), the more expensive for render. Actually, I rendered the half of my scenes barely, but after them, the primitive will be dense in earnest. To solve, I reduced polywire's Divisions and Segments but too many primitive causes expensive render time after all. Then what I was thinking after is to use the concept of Fur such as fur density using texture map. ? , but I couldn't get the clear idea from that, It might be too challenging for me. Or remove polywire out of camera view or at the back of it from that? Or using hair shader? but in this case, it's too late for me... How can I solve this matter with this setup using polywire to reduce render time? Any suggestions would be really appreciated. Due to attached error, add google drive link with images and a simple hip file. https://drive.google.com/drive/folders/0B2PqEaLsEVgWZlBZVGJoc29GYms Thanks, Lee
20. ## Clustering geometry using primitives

Hi Everyone, I have a quick question that I was hoping someone would be able to help me with. I'm trying to fracture a wall, and follow the brick pattern, rather than standard voronoi shapes. Part of this process is to generate a brick wall, fracture each brick, then cluster the results in a meaningful way. Currently cluster is being controlled using the P attribute, but I would like to cluster based in the primID, so that whole brick pieces will be contained in the cluster and not just individual points. Does anyone have a suggestion? My test files are attached. Thanks wall.rar
21. ## Use grouped primitives as a single primitive

Hi, I have a problem which I don't know how to solve. In short I have a geometry objects which are grouped in few different groups. My objective is to use PRIMITIVE SOP after grouping the primitives, but I would like the groups to act as though each of them is a primitive. In the attached example, the pink group is group_01, the rest is group_02 and if I apply PRIMITIVE SOP to it and do some translations, I would like to move the grouped primitives together. Any ideas on how to solve this problem? Like this
22. ## [SOLVED] Help with creating a persistent plexus effect

Hey everyone, I currently have a plexus effect by blending a few tutorials together (tinytuts and Danil Krivochko). I'd like to take it a step further and create a persistent plexus effect where the connections at frame 1 remain throughout the simulation- never breaking or creating new connections. I have this code from the tinytus tutorial: if (ptnum % ratio == 0) { int myprim = addprim(0,"polyline"); int nearpts[] = nearpoints(0,P,maxdist,maxpts); for (int i = 0; i < len(nearpts); i++) { addvertex(0,myprim, ptnum); addvertex(0,myprim, nearpts[i]); } } It's creating primitives based on nearby points. So in order to get the persistent plexus look, I need to use maxdist and maxpts to create the look I want, but be able to keep max distance from influencing the connections after I get my initial look. I think I need to start by establishing a connection between points at frame 1, so they remember who they were connected to during the simulation. I might be able to do this by somehow storing nearpts[] data into each point with an attr? Or maybe I can create a new if statement that says in pseudocode that may or may not look like python: int nearpts[] = nearpoints(0,P,maxdist,maxpts); if frame == 1: create a list called initpts and store any points from nearpts[] into this new list else: pass Then change the for statement to say for each initpt in initpts: addvertex(0,myprim, ptnum); addvertex(0,myprim, initpt); Is there a way that I can utilize python to create this effect here? Another thought I had was to use a solver sop because I've seen that it can calculate what went on the frame before, but I'm really struggling with how to proceed with this direction. A nudge in the right direction would help me out a lot, thanks! Here's my file so far. od_persistantPlexus.hiplc
23. ## connectivity

Hey guys, I have imported a tree in houdini, but since it only has one primitive when I load it in I am using the UV Connectivity option in the connectivity to split the geo up in more primitives. (I am trying to give each branch their own ID). That all works great, the problem is that the attribute BRANCH_ID that equals 0 is not the root of the tree and that messes up the hierarchy I am trying to put together. Is there anyone who knows if it's possible to renumber the primitives in a controllable manner? Cheers, Eline
24. ## H13 w attribute about pack primitive

hi everyone. i make the angluar velocity in SOP. and inheritied Point velocity in DOP. (i was modify RBD Packed Ojbect DOP like H14. this allow Overwirte attribute.) but, doesn't rotate in simulation. what made the wrong w attribute or i missed something??? i shared my hip. thanks for your read. have good day! w_attribute.hipnc
25. ## ROTATE PER PRIM HELP

hi there, please help me with these, i have spend alot of week for these, and still stucked.. basicly i want to try to rotate perprimitive base, effected by color and rotate some degree..but yeah, im still alot of learning with these.. i have recreated on my daily tools cinema4d, and its just required some step to achive fx that i want...but for some reasond i want more freedom with those fx....so i jump to houdini... please anybody on these forum help me with these... i got help from official site houdini forum...and got helped..but still got error for the rotation... i upload all the file, from the refference video, and all the houdini file i created and got helped... thanks.. help please... the reff video: jk_rotate_with_n_124 (1)_helped.hipnc rotate_per_prim_needHelp.hipnc
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