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Found 53 results

  1. scatter points on animated mesh

    hey! I'm about to create a fairly simple effect where a deforming mesh (a man running for instance) is made of spheres, not only on the surface but inside as well. Of course I can scatter points inside, but my question is how can I keep the distribution of spheres constant through the animation so that each sphere moves with the body (and on top a little noise to make each sphere alive...) a good example is this video at 1:32 any tip? cheers!
  2. hou.Geometry.point() not working..?

    Simple problem: I have a foreach loop running over points on a curve each with an attribute that is randomized for which variety of geometry it needs to use. The varieties are coming from 1 input, but where each variety has a different primitive attribute for which variety it is (I get the geometry in from Unity). I got the geometry getting piped in to a copy to points node, in the foreach, but before that I need to delete, per loop, what is not used. Or I need to pick it, I don't know. I just need the loop to select a variety based on the randomly generated attribute. So the way I did it was with a delete node, with an expression with the following python code: curVal = hou.pwd().curPrim().attribValue("namechoice") compareVal = hou.node("../foreach_plank_start").geometry().point(0).attribValue("nameselect") if curVal != compareVal: return 0 else: return 1 Comparing the primitive attribute (int) with the point attribute (int). But.. I get this error: Error: Unable to evaluate expression ( Traceback (most recent call last): File "<stdin>", line 3, in expression AttributeError: 'Geometry' object has no attribute 'point' (/obj/worknode/fence_maker/delete2/filter)). Explanations to why hou.Geometry.point() is not "valid", suggestions for other ways to code it or suggestions for other way to do the network are most welcome!
  3. Hi everyone! I need to do a local rotation using an Attribute VOP for individual points of a grid and just can't get my head around this... If I e.g. rotate along the Z-axis and THEN rotate along the Y-axis it again rotates over the world's Y - not the shifted local Y-axis with a new orientation after i rotated over Z. What I basically need is taking the newly oriented "local" axis into account - the Y-axis should always point upwards from the upside of a cube. No matter how the cube is oriented. I hope you guys know what I mean... i attached an image to clarify. Also I attached a very simple example with 3 Attribute VOPs for rotation over each axis. No matter how the cube is oriented, it always rotates over world-axis. Maybe somebody can point me in the right direction? testrotation.hiplc
  4. Mass in General

    Hi people, I'm trying out Vellum in Houdini and I was wondering how mass works. I noticed that the mass is a point attribute. That said, if I want to know the total mass of the object, do I need calculate the sum of all the points ? Thank you.
  5. Hello guys, Is there a way to create to dynamically create curve point custom handles ? I know I can create a simple curve in HDA and export the curve handle to the HDA, but I can't animate the curve position and edit the curve after. The curve node doesn't take account of the transform node, so it's a bit wierd to modify the points of the curve when the result is 100 meters away. Any help would be appreciated !
  6. Hello Odforce, I'm trying to create groups based on the @P.y attribute of a bunch of vertical lines I have. I am almost there, but I'm not exactly a Vexpert and can't figure out exactly how to assign multiple groups with different names. I'm able to create a string attribute with the correct name for the groups with s@test = sprintf("%f", @P.y); s@groupname = concat("group_", @test); I tried using setpointgroup(0, @groupname, @ptnum, 1, "set") after this, but it didn't do anything, now I'm just stumped on how to approach assigning this attribute as a group. Any input would be greatly appreciated! Thank you
  7. Hey magicians, Been getting crazy with wire solvers. I think the issue is because I get the points changing over time and the constraints go crazy. I've been reading that I need to create a id attribute with $PT to hold the value, tried that with no luck. Animation works fine until the number changes Any tip will be super helpful, thanks in advance.
  8. Hello, I have a feeling this is a common issue, but its a bit hard to explain / search for a solution. I've imported an animated alembic file, used unpack to get the points and put it through a trail node to get the point velocities, the problem is that the point count changes as some of the objects "disappear", so you get brief flicks of extreme velocity as the point IDs shuffle, I am curious about the method(s) for dealing with this problem.. Thank you
  9. hello guys. I am new Houdini user. I got a question about copy to point. I can't find out a way to get each sphere scale from 0-1 when every time it generated in this case. I need some help to know about the concept to make it happen please. thanks. here is the file link: copy to point file
  10. I got this dla growth system, that generate new points from "old" points each frame. i want to instance different objects to the growing dla system. My problem is that when i use an attribute randomize "pscale" and "orient" to the growing points, that result that each point changes size for each frame, same goes for orient. Ive put my randomize in the solver, and was hope that would do it, but no luck. I guess i have to give each point a id attribute once its born, but not sure how to proceed. I went through entagmas toturial "Diffusion Limited Aggregation", that is where my dla/growth system is from, so im just going to give ewach point a randomize pscale and orient. Anyone know how to do this? dla_attribute_problem.hiplc
  11. Hey all! I have a bunch of points travelling around, and I would like to create a new set of points, where each of them is orbiting around the given point, in the direction of the main point, I guess the image attached explains it a little better than words...just trying to do it with vex code cheers
  12. I'm trying to build out an idea for an HDA that would create a vine along a surface based on a find shortest path SOP and some controllers for where the start and end points would be to control how long the vine is. This is mostly intended to be a tool in a realtime engine with the idea that it would be cooked into a static mesh (so it doesnt need to animate). I have the main branch generating fine but I am attempting to create some branching points from the main curve to create child branches from this main branch. However, I'm fairly new to Houdini and kind of stumped where to go from here. Currently I'm scattering points from the main branch and attempting to drive them away from the main branch while following along the surface normal of the underlying mesh. I've got something really basic(just sending them out at a random vector direction and snapping them to the surface) but I feel as though this method doesnt give me any control. I thought about trying to make the branches use a find shortest path as well but Im not sure how to control where the start and end points would be procedurally, hence why I was trying to create curves along the surface normals in an attribute wrangle instead. I attached a .hip file for anyone willing to take a look. Thanks for any advice, I appreciate any pointers in understanding VEX better. IvyGrowing.hip
  13. Hello ! I'm struggling to analyse points from a mesh and only keep x number (like 4?) of the farthest points from each others. I tried to grab the distances in vex then using delete node but its not working properly, didnt find a way to parse every point and compare between them. Tried average but then again I dont know how to compare each points from each other. Thanks
  14. Hello Guys. I got stuck here in a middle of an project and i can't find a solution. My problem is : I have a grid of points , and an animated point running over the surface of the grid. My "running" point have an attribute that is transferd ( via attrib transfer SOP inside anSolver) to the grid points by an proximity radius. then I use the transfered attribute to isolate only the grid points that are tuched by the "running"point. But the @ptnum of the remaining points is changing. And i need the @ptnum to grow in the order detection ( @ptnum 1, 2, 3, 4, 5 etc) why is that happening to understand better I've attached the scene file ptnum_chaos.hip
  15. Hello! Normally I always find the answers to any Houdini issue that comes into my way, but this time I decided to finally communicate my current issue! My first question ever in odforce hehe So well... I'm doing my graduation film, and is about a shepherd that transforms sheep wool into clouds for doing rain! After some previous phase of research, we decided to give the wool a "cloudy" look, more than giving clouds a "wooly" look. So I'm using volumes to recreate the sheep wool! Thanks to various threads made by countless users here in odforce, I was able to: *Create interesting noise density values for the VDBs, hence giving a "wooly" look to the volume. I wanted "puffy" looking volumes, so I scattered particles in the sheep mesh, and created VDB out of them. *Transfer spatial transformation data from an alembic animated mesh to a volume, this way helping me to maintain the overall noise that will have otherwise been calculated at each frame if I moved the mesh I used for the VDB creation directly. *Deform the noised volume through a volume lattice technique by Juraj Tomori and Matt Estela (I'm enormously grateful for having shared their hip files!!! They saved my life). The volume will keep its noise while being deformed by box, itself deformed by an edit or a bend node. Up until now! Everything is going well! The only issue I have is.... How can I assign the point cache information of an animated lattice in Maya to a box with the same dimensions and subdivisions in Houdini? I thought that maybe an attribute transfer I could transfer the P data.. But I don't know if I need some vex to grab the position of every point in the lattice an assign them to a new matrix... I have no idea.. But knowing how to do this will be excelent! This way any lattice deformations the animators will do in Maya will be directly fetched to the box in Houdini! Any ideas?
  16. In older versions of Houdini I could add a point to a group's selection. Has that changed in H16 because I can't seem to get it to happen? Any advice would be appreciated. Thank you David
  17. Hello! Sory for my English I'm trying create geometry with AttribWrangle node in Detail mode. I use addpoint, addvertex and addprim nodes. When I created some points how could I get access to them into the node? For example, I created point pnt0 = {0,0,0,}. And now I want to create point pnt1 which is close to pnt0: int X = 3; int pnt0 = addpoint(0, set(0,0,0)); int pnt1 = addpoint(0, set()); - and here I want to get position of the first point and add X to each coordinates. Is it possible?
  18. Hello, I'm doing this Mold forest..I'm struggling with the UVs.. I have this tubes like structures , I create two groups , the bottom and top rings ....so I can run a shortestes path node to drw the seam path , the problem is that I must have one of this two groups with only one point per ring to draw only ONE path... This Tubes are part of a model wich I split on threee parts, the floor, this tubes, and the tips.. for the tips the technique works perfectly so you can see what I want to achieve on the hip file ... It's difficult to explained I guess... This image show the top ring group.. Fungus_67.hiplc
  19. I am trying to scatter some points on a circle. But I want the points to be scattered more near the center and less towards the outer side. In the old Houdini Scatter I could do it by making my Circle Primitive type to "Polygon" and then uncheck "Divide Non- Convex Polygon" on the scatter node. However, in the new scatter node of Houdini 14 and 15, this option is not available. Here is what I am trying to achieve, this is with the old scatter node. This is what I am getting with the new scatter node. Please help.
  20. Hi, I create a new project but have a new problem. use to source object its has not problem but when added the point on source objects its changing rotation. I hope, you can help me for ı can fix my files.
  21. Getting point neighbor in Python

    Hello dear community, I am currently trying to setup a city generator as part of my bachelors thesis. For a basic street layout, I am using a voronoi sop on a plane and fuse these points. It would be a big ease to be able to find the neighbors of a point (not vertices) and get their position. I did some workaround by creating a dictionary with position vectors and counting the positions that match, so I can at least count the neighbors. Does anybody know a trick or a function to do this in pythin? I know there is a VEX function that does that, however I don't know VEX pretty much and I am having trouble understanding their usage, although I read the docs. Any kind of help would be much appreciated. Best regards, Nicolas
  22. Hello, I know that there are plenty of examples of vop loops with point clouds, but after searching, haven't found an example/file that helps with this. I can get an attribute growth going with the basic like pc_filter and all of that, but now was trying to make that attib growth happen one point at a time(the closest ones from the points with the attrib initiated) and i can do that for the first point, but after that it doesn't do what i was expecting it to do, stops the growth after finding the first point... Imagine it should be something super simple that i got wrong, but if someone could take a look and let me know what i'm doing wrong i would really appreciate it. Here's a simple file showing where i'm at now Big thanks M odforce_pc_loop_problem.hip
  23. I have primitive groups set up in SOP level, something simple like a box with a voronoi fracture applied with the inside and outside primitive groups. How can I access this primitive group in shop context? I am trying to compare whether or not a shading point belongs to a specified group so I can create a mask. I can create a attribute at sop level to store the group information on the points and that works, but I want to do this in the shop context because the geometry will be heavily subdivided and displaced and I need the accuracy. Any thoughts?
  24. Hey guys, I'm having an issue where the Alpha displays properly in the viewport but doesn't work when rendered. I've done this before, just a simple Constant shader, and it always worked. Here is what it looks like in viewport vs render: I looked at other threads and none of the solutions work in this scene. Here is the scene file: 0007_odforce.hip Thanks!
  25. Hi all, I have a problem with wrong point normals. Basically I have an L-system vine which I am deforming with Wire Deform SOP. I am separating the 'anchor points' of the leaves and I want to add the leaves back after the Wire Deform SOP (if I keep the leaves geometry together, the wire deform screws up the leaf geometry). I also want to do it this way, as I want to control the leaves animation and growth with copy stamping which won't be possible if I keep everything together. But if I separate the anchor points and then add the leaves back with copy SOP, the point normals are different that those I would get if I deform the whole L-system together. I hope it makes sense, any suggestions how to fix it would be greatly appreciated. I attached screenshots and my .hip file with both set ups. Correct normals, screwed up geo: Wrong normals, correct geo normals_lsystem_problem.hipnc
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