# talen.herzig

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11

1. ## Wall Fracture Set Up Help

Hi all, I'm playing with dynamics of fracturing objects and I'm wondering how to go about setting something up properly. What I want is a wall that fractures upon impact, but holds together prior to that, and only fractures at impact points where there is enough force to do so, with the basic effect of a wall that, when hit with a sphere object, only fractures at the geometry closest to the impact point. Similar to say, concrete being hit with a heavy object. Using the Voronoi Fracture nodes in the geometry object, I've created the wall fine, but when I turn it into a rigid body object it immediately starts falling apart. I've tried glue constraints, but they don't seem to hold it together as well as I would like and as soon as the object it hit, it still falls apart much more than I'd like, and often pushes the entire wall back until the shatters against the ground plane. I've also tried using pin constraints at the bottom and sides of the wall, but it didn't help hold the wall still. Firstly, am I using the glue constraint wrong? Should I be able to get the desired effect using the glue constraint, and if so, could anyone point me to a tutorial that would help me understand it's use and limitations better? As a potential solution, I was considering setting all the geometry to be passive using an Active Value node except where the impact force is greater than *value*, but I am not quite sure how to go about this, or how to set up the necessary attributes. Any help would be appreciated.
2. ## Wall Fracture Set Up Help

I think I may have been misunderstanding how the pin and glue constraints worked, as well as exactly how high you have to set the glue constraint to get the correct result. I may have to play with it a little more. What I did was create a pin constraint, remove the goal object, and change the constrained object to "piece*" instead, with the wildcard, then create a glue constraint on the object with a much, much higher strength. It gave me a lot closer to what I wanted, and pinned all the pieces a little bit better. I get the feeling that to get any better will require being a little more specific in what I feed the Voronoi Fracture nodes in the geometry object. Does anyone else have any advice on what might be a good way to use these constraints, or is it kind of arbitrary trial and error to get results?
3. ## Intersect Node in Point VOP

Hi guys, I'm working on the following project: https://www.sidefx.com/index.php?option=com_content&task=view&id=2569&Itemid=389 Specifically, the pin table at the end of the project. My problem is that when he uses the VOPSOP in H12.5, the intersect node is different, particularly in that it has an option for "Furthest from ray origin", which doesn't appear in the Point VOP in H14. While I understand what he's doing, I'm not entirely sure how to replicate it without that option within a Point VOP, so my results are completely off. I can't figure out how to calculate the distance between the two points, especially when it comes time to try and calculate any form of overhang, because it's not calculating the bottom points accurately at all. Can anyone point me in the right direction? I was thinking there might be some roundabout way to do it with the Intersect All node instead, but I can't put my finger on what it might be that doesn't require a damn sight more work than it should have with the VOPSOP option. Also, is there a way to bring in the old VOPSOP, and is there a reason why I should be using the Point/Attrib VOPs instead? This isn't the first time I've had this sort of problem, where something seems to be way more complicated to do in a Point VOP than a VOPSOP because there's a node or option missing in the new VOPs. My scene file is the effect attempt.hipnc, and the lesson scene file is also attached, pins_003.hip. Thank you in advance, I appreciate any help. pin table effect attempt.hipnc pins_003.hip
4. ## Particle Stacking Effect Help

Hi all. I'm trying to create a particle stacking effect, where the particles collide with a surface and stack on top of each other. However, I'm not entirely sure how to go about this. I'm using volumes, as I saw in a different video, but cannot quite get the expected results. Upon collision with the ground plane, the particles are stopping and creating the collision volume, but it's not growing on itself. Any help would be much appreciated. I'm quite new to the volume aspect of DOPs, so I'm not entirely sure how to get it all to work, nor why the particles aren't growing the DOP. I've tried tweaking quite a few settings and playing with this over the last hour or two, but once again am not sure what I'm missing. Please find the .hipnc file attached below. Cheers. tasty soup v5.hipnc
5. ## Intersect Node in Point VOP

Hi MCGrund. I thought the distance was included in the Ray Direction before? That was my understanding, anyway. Is there a way you got that Intersect node to ignore the closer intersections? The documentation states that "In the case of multiple intersections, the one closest to the ray origin will be used". I'm half tempted to just use the old function with the farthest parameters and do it via VEX with that, but that seems like a less responsible way to do it since I have no idea how it actually works specifically, just that it still does.
6. ## Particle Stacking Effect Help

Oh man, that is a much faster and easier way to do it. I watched this fantastic tutorial below (for any looking for similar solutions) and got it working much quicker. And it computes so much faster. Thanks, sultan!
7. ## Path CV Point Normal Issue

I've been going through the tutorials listed on the SideFX website for Houdini lately, and I've had an issue with the first tutorial in Procedural Modeling where Ari is making a hose that follows a Path CV object. My issue is that no matter what I do when creating the path, my normals are not aligned along the curve as his are in the downloaded scene files. Instead, the normals of all points point perpendicular to the path. This causes issues later when trying to manipulate the path to pull the end points in/out to carve them and create tension. Instead of having the desired effect of moving the points in or out along the path, they move along the Y-axis, which is how the normals appear to be oriented. I can't find any steps that I've missed, having combed over the lecture yesterday, and cannot find any options to change how the normals are oriented. As well as this, all my attempts to correct the issue have failed, including manipulating the normals in a VOP, trying to use a Point SOP to change them, and experimenting with the Polyframe node. What am I missing? Thanks heaps for the help, this one has me stumped and I can't figure out if I just missed an important step, did something stupid, or am suffering at the hands of Houdini 14 when he used Houdini 12 for this tutorial.
8. ## Path CV Point Normal Issue

That's an interesting alternative. I come from Blender and Maya, teaching myself over the last 6 months a variety of software, and I'm still getting used to the idea of different attribute levels. Wouldn't have even thought of the detail attribute level! Will have to keep that in mind in future when coming up with solutions. Thank you very much for your help.
9. ## Intersect Node in Point VOP

So, in an unexpected turn of events, the VOP SOP still has the same version of the intersect node, which doesn't have the option either... it appears the only way to get that particular version of the intersect node is to copy and paste it in from the lesson files, lol. That's disappointing... The only thing I can think of to try and do is to perhaps come up with some way to create a loop system that keeps running the Ray node until it detects no more intersections, but that seems inefficient and wasteful and I'm not sure how to implement it either. EDIT: I copied the VOP SOP from the lesson into my project, and it worked fine. I tried to view the VEX code for the VOPSOP to see if there was a way I could get the same functionality of the intersect node in a Wrangle perhaps. However, the intersect function in the code doesn't match any of the intersect functions in the H14 documentation: prim = intersect(file, P, product, pos, u, v1, "farthest", farthest); I can't find any version of that intersect function that takes those parameters, so I'm still stuck being unable to use it effectively. So, that sucks.
10. ## Intersect Node in Point VOP

Thank you, that's enormously helpful. Sadly, even half the time when I look at the VEX node examples in the help documentation, they seem to still have the VOP SOP haha. I think I'll end up using this more often until I actually manage to master the software enough to be able to get creative with solutions later down the line. From what I've read, it seems the new VOPs are more efficient but I doubt it will make a huge difference to anything I do any time soon.
11. ## Path CV Point Normal Issue

You know, I could've sworn I'd tried that with the polyframe node and it didn't work, but I might've tried to do it in a point wrangle instead and muddled it (only been learning Houdini for about 2 weeks now). That's fantastic and does work thank you kindly. How would you tackle the imaginary last + 1 position? The only solution I can come up with for that is to check if it's the last point, if not, use the above line, if it is the last point, orient the Normal to "last - 1" and reverse it. Is that about as efficient as it would get? I can't see any reason for that not to work.
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