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Everything posted by Farmfield

  1. glue network and deforming mesh

    What needs to be tweaked for stuff to work is of course individual for each setup, but if you conclude the issues you have are connected to it being delayed one frame, then you of course gotta timeshift it in place. I'm in the middle of doing a thorough refresh and read-up on my dynamics skillset, and this last week I lived and breathed constraints - you caught me at the right moment so to speak.
  2. glue network and deforming mesh

    Yes, you would have to do that. Constraints are lines, two points with a name point attribute telling them which piece to attach too and two primitive attributes, one for constrain_type for position, rotation or both (not the type as in glue, pin, cone, that's in DOPs) and a constraint_name which is the data name you link it to in the constraint network node in DOPs. (*) So if you have a changing mesh, you will need to reposition the points per frame - but you don't have to do that manually, if you have a setup procedurally generating the constraints from the mesh, you just need to set the "overwrite with SOP" in the constraint network node in DOPs. If you don't have procedurally generated constraints or want to control them very specifically, you gotta set that up in a SOP solver in DOPs. (* That's the basis for a constraint. Then you have a ton of point attributes you can use to set strength, constraint angles, etc, but you gotta read up on that in the constraint network help, it's just too much to cover here.)
  3. simple cloth tearing for fun

    Whatever else we conclude, we at least know you know how to properly name parameters!
  4. How to have animation driving dynamics? rotor blade

    A constraint is a line with attached (string-) attributes. For the primitive you have constraint_type (position, rotation, all) and constraint_name (the reference/data name) and for the points you have a name attribute where the string for which piece. I just had no time to do a complete setup, but here's a quick setup for the constrain in SOPs and DOPs - I hope I didn't miss anything. Edit: F!, I did miss something, for a rotating constraint, you need a rotation axis, you set that with a point attribute in SOPs using a directional vector. If you don't figure out how it works, I'll do a complete setup tomorrow. constraints.hiplc
  5. How do i Re-time /Slowdown A pyro Nuke explosion

    Hmm, I don't see why it would be needed, but try putting quotes on everything (after the equal sign) and see if that helps. other than that I really can't see why it wouldn't work.
  6. Is a single point "geometry"?

    This is purely a semantic question and I mean in terms of 3D graphics, not math. (though perhaps there's no such distinction) Or is this like asking if viruses are alive? (but please let's not have THAT discussion, hehe ) My thought is, as a point technically is a (graphics-) primitive, it is geometry, right? But as I might be completely wrong, I thought I'd come here and start a lively discussion about it.
  7. Is a single point "geometry"?

    I phrased that really badly, over complicating it. The question was as simple as, are the render attribs for points and lines on them or is it presets in Mantra - and I thought it was in Mantra. Sry. But thanks, guy's, not the most important thread from a practical standpoint, but it's just nice to know the border between primitives and geometry, which is kinda what the answer to the question was all about.
  8. How do i Re-time /Slowdown A pyro Nuke explosion

    LOL, just take away the [* * ] stuff - just add the path. That's on me, trying to make it obvious, I made it look like something complicated, otherwise it's as it should be. QLIB = /path/to/qlib/root/folder/here/ QOTL = $QLIB/otls PATH = $QLIB;& HOUDINI_PATH = $QLIB;& HOUDINI_OTLSCAN_PATH = $QOTL/base;$QOTL/future;$QOTL/experimental;@/otls;& HOUDINI_TOOLBAR_PATH = $QLIB/toolbar;@/toolbar;& HOUDINI_GALLERY_PATH = $QLIB/gallery;@/gallery;& HOUDINI_SCRIPT_PATH = $QLIB/scripts;@/scripts;&
  9. How do i Re-time /Slowdown A pyro Nuke explosion

    Aah, seems there's not a default houdini.env on mac so just add one, create a text file in the houdini15.5 folder and name it houdini.env and paste the stuff I wrote, changing the path to where you unzipped qlib.
  10. How do i Re-time /Slowdown A pyro Nuke explosion

    Cleveland in '86, Egypt in '93, Paleochora in 2014, lots of places. Naeh, been drowning in RBD and Pyro refreshing & RnD - that's why I dove in here too, I'm gonna add the retiming to my Pyro RnD curriculum. And the Nuke looks great as a still, looking forward to see the sequence and a breakdown when it's done.
  11. Is a single point "geometry"?

    Well, not as much philosophical as me wanting to use the correct nomenclature, talking about these things. As for points as practical, I think I got most of that covered, I started messing with particles and point clouds in Softimage 3.x, damn, those were the days. You think? With that title, you just state a yes or no and that is law. But you say it just has a position, then I wonder, is the default point render in Mantra, that if you pipe in a point without attributes, it uses a preset, or are there hidden intrinsic attributes attached to it at creation to set that?
  12. How do i Re-time /Slowdown A pyro Nuke explosion

    It's all in the houdini.env, you got nothing you need to add in the global environment in OS X. There's nothing in the Qlib stuff that is OS specific, it's all xml, python and otl's. Just pop this into your houdini.env and you're a go! QLIB = [ * path to qlib root folder here * ] QOTL = $QLIB/otls PATH = $QLIB;& HOUDINI_PATH = $QLIB;& HOUDINI_OTLSCAN_PATH = $QOTL/base;$QOTL/future;$QOTL/experimental;@/otls;& HOUDINI_TOOLBAR_PATH = $QLIB/toolbar;@/toolbar;& HOUDINI_GALLERY_PATH = $QLIB/gallery;@/gallery;& HOUDINI_SCRIPT_PATH = $QLIB/scripts;@/scripts;&
  13. Is a single point "geometry"?

    I supposedly was an engineer, at least on paper, some 20 years ago. Though I think I had forgotten most of the math, material mechanics, etc, after a decade of not using it much. Getting into Houdini these last 1-1/2 years has been a fresh start for sure, in regard to math. That being said, I still believe having renovated a couple of old Land Rovers was the best prep for Houdini I had.
  14. How do i Re-time /Slowdown A pyro Nuke explosion

    Dunno how far you can take a retime in Houdini but when you are at the limit, you could probably push it a bit more, retiming the render in comp using Kronos in Nuke or alike.
  15. Is a single point "geometry"?

    Well, they have a default width in Mantra, as points have, but as you said before, width a 0 width or pscale, it won't render. I'm well aware... My question had nothing to do with anything practical in Houdini, though, I was phrasing a statement about points when I started thinking about what they actually were, in regard to nomenclature - or rather, what constitutes geometry, if you turn it around. I'm in preparation for doing some more stuff as the thing I wrote for Gridmarkets, so that's what this was about.
  16. Is a single point "geometry"?

    Well, it's kinda fascinating, this whole subject. Like a primitive (as in polygon) in XY not existing in Z, to the point where you can't select it in the Houdini viewport as it has no surface to select. But you can select it's edge, because that's a definition. I'm just glad I'm in Sweden and not Colorado, imagine getting into this high on pot. xD
  17. Is a single point "geometry"?

    Hehe, that's not true in Houdini, though, as points render as primitive spheres as default - but I agree. I define a point as a location, so that's not something. I'm not sure, though, that my definition is correct in terms of terminology - which is what this is all about, or rather, my first post is. My current hypothesis is a point is a primitive and that primitives are not geometry but geometry representations.
  18. Is a single point "geometry"?

    The question would be answered by the answer to if a a graphics primitive must be a geometric primitive? Because if it is, a point would be geometry. But I suspect that leads us into the "is a Virus alive" thing. * Edit: Suddenly I'm starting to think that object primitives (like a primitive sphere) probably isn't geometry either, they are geometry representations, so that would make a point non-geometry. * The circle thing is weird, though, a circle is a curve - but then again, a curve with an infinitesimal length, would be a point (I guess). Now, this is of course not very important, but I was phrasing a description of a point and the question popped up in my mind - and it's kind of an interesting question, though it's lack of much relevance.
  19. RBD Orientation

    Yeah, I thought that was the likely reason. My mode is almost always to try to minimize the number of nodes, I'm always thinking "how can I simplify this" - because you almost always can. Though I do love to add nulls to keep my node trees looking nice. Sometimes a bit too much. The question is if adding a solver like that will create any overhead or if it's redundancy basically makes it a passthrough. Not really relevant in a setup this small, but doing some 2012 type California is crumbling, falling into the Pacific with a trillion RBD objects stuff like that have a tendency to make a huge difference. And thanks for the scene file, it's a really interesting setup using a slerp to ease out the jitter. I'm at the point where I can understand what a setup like that does, but I've got a bit to go before I can do them myself - sometime, long time in the past, I was supposedly an engineer, hehe, but I'm basically resurrecting my math skills after 20+ years of not really using them, it more or less feels like I'm starting from scratch again. At 45. Don't thank me, I just took Davids great work into a fitting scene setup to show off how well it worked. All credit goes to him.
  20. RBD Orientation

    Yeah, I played around with forces and drag, trying to balance it out - and sure, it gets better - but smoothing the velocity over three frames makes it a lot calmer, I think upping that to 5 frames would solve the issue completely. I just don't want to have to split it up in two wrangles - or perhaps there's a way to access offset frame attribute values in VEX, though I didn't find anything in the documentation... I just checked your setup, yeah, it's about the same as I get smoothing it over a couple of frames. Here I tweaked drag and forces too... I gotta ask, though, why are you using a multiple solver for the POP forces? As you already have a multiple solver in the RBD solver, they plug right in. And that VOP, damn, following other people's reasoning in VOPs is always a lot of fun...
  21. RBD Orientation

    Very cool, David. This was the first major question I had, migrating to Houdini some 1-1/2 years back - and I actually never got it solved, well, not as I would have wanted to solve it. But yeah, this is how I would have wanted to do it. Now, I did a really crappy smooth function using timeshift and a wrangle, but there's just gotta be an easier/better method to do this, right? And over more frames - 5 would do I imagine. Or perhaps there's another way to get rid of the jitter when velocity is really slow? For a moment I started thinking about doing a velocity based multiplier for the alignment, but then I realized I had nothing to multiply, there's no amount of alignment, it's just aligning. packed.align.to.vel.v1.hiplc
  22. Clustered Smoke With Particles As Source

    This is why you should avoid the shelf tools and set stuff up manually - the second it stops working as expected, you're lost. When you come to the point where you don't really need the shelf tools, then you can use them out of convenience. In this case, somewhere in the clustered smoke setup it looks for the primitives of an input geo - a particle system have none. So if you pipe your particles into a copy and copy a sphere on each, then add the clustered smoke, it should work.
  23. Clustering without fracturing?

    The math is one thing, there I know you have everything in check, I'm thinking more about attributes and how to manipulate them, stuff like how you can promote from point to detail and back just to extract a max value, stuff like that. A good example is in the cluster_geo.FF.v1 scene file where I used a foreach over primitives to set the clustnum of all points in a piece to the clustnum of the first point of the piece. That's what I'm talking about, those very Houdini type solutions. Well, I know you're gonna get full control over this, just trying to give you some pointers from my own experiences coming from Max to Houdini.
  24. Clustering without fracturing?

    Hehe, exactly my point, you wouldn't have been (at least as much) if you had better understanding of SOPs. Knowing your journey, having done it myself, I can tell you the stuff you need to know to do cool stuff in DOPs, is in SOPs - so you should get a good grip on that first, then move onto RBD, the gas and FLIP solvers, etc... Starting at the other end, it will take you a long time to get what you need to know to control your sims - and that's what dynamics in Houdini is all about, control, directability, etc...
  25. Clustering without fracturing?

    This might sound a bit counterintuitive, but I think in Houdini, even if you are an FX guy, I would recommend getting into all the attribute and wrangle stuff in SOPs, not in DOP's. Because it really works the same in DOPs, but it's so much more involved, directly, it's a bit much to take in. That's why I'm doing these small RnD things all the time, I'm training myself to work around the kinks of my own mindset, working in Houdini. But if I need to do a huge dynamics setup, it's all going to work the same, just in a more complex setup. Take constraints as an example, they're just lines with attributes, thus, messing with constraints when you set up a sim, that's in SOPs, not DOPs. Even in DOPs, when a constraint is broken, it's removed in SOPs using a SOP solver, etc... Here's a simple setup just to illustrate how you could use this. (edit: and yeah, I set that up deliberately confusing as an illustration, hehe, but it's simple enough to figure out I hope - think 'where does the color come from') sops.in.dops.in.sops.hiplc