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pfistar

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pfistar last won the day on March 17

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About pfistar

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    Nik Pfistar
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  1. Deleting RBD Clusters for Splintered Wood Effect

    @underscoreus I gave the Assemble SOP a try and indeed it does exactly what I need it to! Many thanks for the quick response! NpF
  2. Hello all, I'd like to know how I might procedurally delete individual clusters created by using a two stacked RBD Material Fracture nodes. I start with a tube and add the first fracture node fractures radially using the 'glass' setting. The second fracture node splits the 'glass' fragments into 'splintered' layers along the y axis using the 'wood' presets. What I'd like to do is delete some of the 'wood' clusters that occupy the upper portions of the tall 'glass' shards. This would expose the splintered wood look I'm going for. I'm at a loss for how to go about this however. I can use a plain ol' Delete SOP, but since there are 500+ clusters, finding them by individual name is unwieldy to say the least. If I'm not using some VEX, it seems the ideal would be to create some setup that would let me create a centroid point for every cluster, then associate the clusters' primitives per those centroid points, then use a bounding volume to select those points, and delete all those points along with all the prims associated with them. Trouble is I really don't know how to set this up. It would also help to know if there's a way to also delete any clusters that fall below a volume threshold. Any help is good help - many thanks! Nik wood_fracture_001.hiplc
  3. Greetings all! I need to align an object to a point (without using Copy SOPs). I found a short tutorial on this that uses a VOP SOP with "Align" and "Extract XForm" nodes. This works exactly as I'd like it to, but I need to rebuild it as it was created in Houdini NC, and is also a few years old so it appears some of the nodes have been deprecated. I did my rebuild approximating the original file with non-deprecated nodes, however, I'm not getting the normal-to-rotation alignment I need and I'm at a loss for where to look to resolve this. Attached are screenshots, one derived from original file (Non-commercial), the other is my re-build (Indie). The results in the Geometry Spreadsheet tell the story. Respective .hipnc and .hiplc files are also attached. Preemptive thank to any responders! NpF N_to_angle_NonCommercial.hipnc N_to_angle_Indie.hiplc
  4. Hi All, Relative noob here looking for a way I might fracture a cylindrical piece of geometry to look like broken/splintered branch. Following Varomix's otherwise very informative tutorial ( https://www.youtube.com/watch?v=3Er9BDDzZHQ ) I can control other aspects of the grain and clustering, but in my case it would be ideal to be able to fracture radially along the y-axis of the cylinder, along the lines of the 'glass' preset, while also being able to do the 'splinter' fractures that bisect along the x and z, which the 'wood' preset allows. Per the screenshot attached, I more or less get the splintering I'm after but grain only slices along a single axis which I'm hoping to make look more radial. Does anyone have any tips for something like this? Would it make sense to run 2 RBD-Material-Fracture nodes one on top of the other, to get both types of fractures? Or is there another SOP or combo of SOPs that could hand Many thanks! NpF
  5. Hi all, Another Noob question here: I'd like create a setup that takes my object A (in this case, a Line SOP) and constrains its pivot position and vector angle to the pos and N of a given point on object B (in this case a mesh object). I'd like to include in the setup, an integer slider that lets me choose the point number. I have to imagine this is a fairly simple thing to do and have been searching for the right tutorial but haven't found it yet. Can anyone out there share a tutorial link, or maybe a VEX snippet? BTW, I'd welcome a VOP solution just as well. Preemptive thanks to any responders! NpF
  6. hi Ryew of Urth I'll certainly check this out and get back to you, as it looks like it might be just what I need. Thanks for the quick response and cheers, NpF
  7. Hello all, I’m a relative noob and while this seems like it would be do-able, I have no idea which nodes I would need to invoke. I would like to map a repeating (but not tiled) texture on an object that already has an underlying material / texture. (So for example, knots on a tree trunk, or pimples on a human face.) The way I imagine this might work is that once I’ve used Scatter SOP to scatter some points on my base object, I would somehow translate those point coordinates to UV coordinates (Not sure how to do this). Those UV point coordinates could then be used along with a texture’s 2D matrix to map its pixel data per point (Don’t know how to do this). I would also imagine I could use a pscale value with some randomization to vary the sizing of this repeated texture (again, not sure at all how to approach this). I'd also imagine I'd want to use some kind of multi-layered shader with alphas in order to preserve the base layer material properties. I should note that I’m using Redshift here, as I imagine this might make a difference as it might have a few more limitations compared to native Houdini texture/materials workflows (though maybe not?). Preemptive thanks to any responders! NpF
  8. Trouble with Creep and Ray SOPs

    Hi Martin Many thanks for the reply and for the investigation! Before I saw your response I did manage to get things working using the Ray SOP to create my creep surface. File is attached. What I ultimately ended up doing was using PathDeform SOP along with PolyFrame SOP to create my initial tube geo and to keep the normals of the tube I was trying to wrap from straying off their initial horizontal direction. The results weren't absolutely perfect, but were good enough to move forward. I took a look at your solution which is far more Zen than mine - though I don't imagine I would have ever arrived there for a couple reasons: 1) My VEX knowledge is nil, save for the most very, very basic things 2) Allowing the vines to criss-cross as they climb the tree-trunk is essential to the look I was trying to achieve, which is why I chose to copy this tutorial over others of a similar nature. I struggled with re-creating the CHOPs networks to get that point-position randomization, but ultimately it gave me the exact effect I wanted. I would bet there are other ways to do this (for example, I haven't investigated how I might pipe the CHOPs data into your VEX-based point set-up), but this one seemed logical to me, and easy enough to control, should I want to art-direct the randomization. Otherwise, yes Carve SOP is totally a friend! Many thanks again for taking a look and for the general advice! Cheers Nik ray_and_creep_forum_npf_followup_4.1.zip
  9. Hi Librarian Thank you for the response. I'm not sure how you changed the file, but I rebuilt again in HoudiniIndie and the process revealed my errors. Per the CHOP net: - it appears I'd had a syntax error in expression in my Constant node. - also, in looking at the graph view, I noticed the cy value was flat rather than ramped (because I didn't think to put a keyframe at the end ) For the ForEach blocks, it appears I was Fetch(ing) Input, (rather than Fetch(ing) Points,) and was also looking for the eval numbers before evaluation had actually happened (didn't realize you sometimes have to manually force it to evaluate). In any event, thanks again for responding and for displaying your inspiring Houdini work. NpF
  10. Greetings all! I'm a relative noob to Houdini and trying to replicate a CHOP network that was created a few years ago for a Lynda.com tutorial. I triple-checked and with the exception of frame-ranges, all my nodes and settings are identical to the original, though the one critical difference (presumably) seems to be that in some of the old network's nodes, the Mode is set to "Constant Range" instead of "Range" (node info comparison here). I can't find the place to change this setting - hoping some CHOP ninja can help! Here's ink to a reduced version of the original tutorial file: https://www.dropbox.com/s/zlj9uujmpkap46v/LyndaTutorial_Reduced.zip?dl=0 More importantly, below is a link to a file that contains the original CHOP network (copy/pasted from original file) next to my 'built from scratch' new CHOP network: https://www.dropbox.com/s/4k4rd01j1ja97a8/ForEach_old_vs_new.zip?dl=0 I rebuilt the network because the original was a .hipnc. In above-linked file, I've wired up some side-by-side node networks to show how the CHOP net should be working (works fine with the original) and how it's not working (with my rebuild). Attached is a jpg preview of what the network looks like - I'm ultimately trying to use the CHOP to drive an array of points up a surface. Preemptive thanks to any responders! NpF
  11. Trouble with Creep and Ray SOPs

    Hi all, Somewhat of a noob here trying to make vines creeping up a tree trunk (image A). I've put together a series of screengrabs along with my .hip file. Project geo peripheral might be a bit too large for attachment so here's a dropbox link: https://www.dropbox.com/sh/87f6okcs4h6a1xa/AAAXy7BdIlo1eJxFCmvkFzkPa?dl=0 I followed Scott Pagano's tutorial on Lynda, where he sets up the 2d point travel as a CHOP and feeds that into an (old school) ForEach net which holds the Creep node and iterates on a series of points. In Scott's setup, the geo surface the vines travel along is created by conforming a simple Tube SOP around an abstract base geo using the Ray SOP. Using this tutorial as my guide, I tried to do the same by using Ray SOP to wrap Tube around my tree trunk model. Because the trunk leans in a certain direction and has some irregularities in its form, the Ray SOP was having trouble finding what it needs to find to get a good, full wrap all the way up the trunk (image B). So, I tried a workaround, where I took the spine line of the tree, Resampled the points, used Copy SOP to clone series of Circles, and then created a surface with PolyLoft SOP. I figured this would line up the normals a little bit better between wrapping geo and tree geo and give the Ray SOP a better chance of finding the surface. Lo and behold this works quite a bit better (image C) however, now the Creep SOP yields an error saying that the geo surface I'm inputting is "not a surface". What's particularly frustrating is that I had it working for a moment yesterday (was able to generate "creeping" points up the tree surface) but can't recall how my setup was any different from now. What's happening now is that the Creep SOP is placing its points on only a single primitive in my mesh (prim# = 0). (image E) I ran a quick test with other primitive geometry objects: a Box, Sphere with top and bottom truncated using a Delete SOP. This was also yielding the "Input is Not A Surface" error in the Creep SOP, and the points were once again bound to the perimeter of primitive 0. It seems the only geo object allowing Creep SOP to let points travel is geo derived from a Tube SOP (image D). I was wondering if the points' travel ability had anything to do with normal angle, so I cranked down the number of sides to its minimum (3) but the points could still creep and travel around those sharp corners, so I'm wondering if it has to do with how the points are ordered on the surface geometry. Or is it something else entirely - ultimately wondering what separates a recognized 'surface' from a 'non-surface'. I'd also ask if anyone knows of a better way than Ray SOP to conform a Tube to my tree trunk surface. Ideally, the Y value of each point would stay in place, so the mesh would be made up of evenly spaced horizontal loops, though of course X an Z would move to conform to the target surface. Preemptive thanks to any responders! NpF houdini creep and ray.zip
  12. Greetings all, I’m a relative noob in Houdini and am having a hard time trying to create a displaced noise on the mesh of a Houdini Labs Tree Trunk object. Though the Tree Trunk node is open for exploration, I don’t know enough to understand why the following is happening: I try to displace points on the trunk’s surface with procedural noise in an Attribute VOP, using a typical setup (Adding the N value to the P value), but the result appears to not push things outward, 1 to 1. (It looks like maybe things are being pushed according to a tiled UV? I can’t quite tell). I also tried using the Displace Along Normal VOP node, but can’t seem to get that working either. On the other hand, when I use an Attribute Noise SOP, I get the effect I am looking for! What is the big difference here? It appears that the noise here is working on the incoming P value, though when I change it to N, I get nothing. There are another 2 components to this I’d like to solve: With the Attribute Noise SOP, the noise displaces the entire mesh off of its center. This appears to be true no matter which range value preset I use, including ‘Zero Centered’. I would attribute this to the notion that only the points’ position values are being displaced according to the noise, and they’re not being added to their normal values for that center-outward displacement. Is there a way to do this using this node? Perhaps with an expression in one of the fields? As mentioned above, I tried to use a VOP for this, but was unable to achieve what I wanted - (I suppose that ideally someone can show me how to achieve what I need using the Attribute VOP in the first place). The other thing I’d like to achieve is some falloff, where parts of the tree mesh are or are not affected by the noise SOP. The only way I vaguely know of to do this is with an Attribute Transfer SOP and a color value run over P value, however, I hit the wall of shame when trying to figure out how to use those color values to drive the noise that drives the point position values. I imagine it can be done in a Wrangle or a VOP. I tried a few things that way, but coming up with zilch. Hoping someone can help a frustrated beginner! File is attached! (WARNING: requires Houdini Labs’ Tree Creator assets to be installed) Preemptive thanks! NpF LabsTrees_Displacement_Test_v001.hiplc
  13. Can I use redshift noise in a SOP as a displacer?

    Many thanks Fred, I got similar responses from folks on the Redshift forum. I will give that a try. Cheers, Nik
  14. Greetings all! I’d like to know if it’s possible to pipe any one of the Maxon/Redshift noises into a SOP node in order to displace geometry on a mesh (rather than having Redshift handle the displacement at render time). I need to do this for the following reason: Maxon/Redshift has the specific noise I want (don’t want to spend a lot of time trying to replicate or approximate using one of the SOP noises). I will need to generate vine growth along the object I will be displacing with noise, so unless I’m mistaken, using render-time displacement is not an option. If there’s some workaround to this I haven’t considered, please enlighten me!!! Preemptive thanks for any responders! NpF
  15. Karma Noob Issues

    @davpe I appreciate your response. I haven't had the opportunity to run any benchmark tests but there does seem to be a little debate on the SIdeFX user forum about the advantages in render speed (Mantra vs. Karma). Seems a few folks claim there's a substantial speed advantage (though Karma couldn't compete with any of the upmarket GPU renderers frame-per-frame). In any event, I started experimenting with Redshift in the meantime and I'm totally sold so far (it's actually part of my regular workflow using C4D). In any event, after some stabbing around and thanks to @Atom's suggestion above, it turned out that the issue was that the Karma (and Mantra) components of my license were being blocked by firewall. Something to do with Karma, I guess Cheers and thanks again, NpF
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