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jamesr last won the day on August 7

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  1. Access NodeA-Paramter in NodeB

    I think I have an idea of what you're trying to do, but having sort of a hard time understanding your terminology. Could you post quick hip with an example of what you're trying to do ? Otherwise, if you're trying to link parameters 1:1, you want to right click the parameter, and select "copy parameter". then in the destination parameter right click and again do "paste relative references". This will make the parameter drive the other one.
  2. disturbance when velocity

    This is the technique they're talking about. I highlighted the nodes in yellow with an explanation for each. Thanks to Stephen Knipping for the trick Velocity is not the same as speed. What you're looking for is to control the disturbance in areas of greater speed. Speed is the same as the magnitude (length) of the velocity vector. The reason you put "vel" into the control field, is because inside the vop we will tweak it to calculate the length instead, and use that. You cannot only enter "vel" to make it work how you want. Gas disturb by default affects the temperature field. Temperature can play a major role in the look of your sim because it affects velocity. But it doesn't do any good if you're not using temperature in the sim, or if you want to affect the velocity field directly. You turn on "control field is vector" in order to get the switch to switch to the correct gas field vop inside. gas_disturb_velocity.hiplc
  3. Oh yeah I see that. I guess that sort of works, but I'd stay away from doing it that way since it's not really working as expected. You shouldn't actually need to put the v@ in the second wrangle in this case.
  4. static gas turbulence?

    Here's a quick hip with the stuff to change in red static_gasturb.hiplc
  5. static gas turbulence?

    If all you want is a static noise field for the pyro to swim through, you can just use a curl noise in a gas field vop. If you want, you can just copy and paste the one inside the Gas Turbulence microsolver inside "compute_turbulence". Inside the gas turb, it uses a vec4, with the fourth component after the position vector being time. So it doesn't matter if the pulse duration is off, it's still moving through time by default, because pulse duration is connected just to the offset parameter. You can unhook this and just use pos (vec3) to drive the position of the noise and run your pyro through it.
  6. The problem is that you're mixing vex variables and attributes. The following code is incorrect (not really sure why it's not erroring out...) @Cd={0,0,0}; vector @a1={0,0,0}; // Here is your problem f@b=0; @Cd=fit01(relbbox(@P), 0.5,1); @a1=fit01(relbbox(@P), 1,0.5); instead of doing vector @a1 you want to declare the vector attribute as v@a1 Here's your file with the stuff fixed. I like to prefix the attributes with f, v, p, 4, etc all the time when I'm coding. You don't technically have to each time, and I don't think most people do, but it helps me avoid any confusion on the type especially in places where houdini is pickier about it, like in DOPs. I also added some spaces to make it a bit more readable . You may want to consider getting more descriptive with your attribute/variable names! q1_fix.hipnc
  7. Here is how I would approach this: 1. Draw out 10 curves. This will give you 10 primitives. Make a merge node and connect them all in there. After that, connect a null and call it something like "REF_ALL_CURVES" 2. Make a primwrangle. Create an attrib called something like "prim_id" and make it equal to primnum (i@prim_id = i@primnum). 3. Make a Null and call it something like "CONTROL". Add an int parameter to it called "cluster" or "wedge" 4. Put a blast node and in the "group" parameter, set it to @prim_id==`ch("../CONTROL/wedge")` and set the entity to "primitives" and "delete non selected". This will isolate one curve at a time 5. Drop another null as a reference point and call it like "REF_CURVE" so you can easily point to it later 6. Do your particle sim as normal. For the curve input, point it to that REF_CURVE null 7. Do your DOP import however you wanna getting the particles out of DOPS. After that lay down your cache node. 8. Inside a ropnet, or the /out context, put a wedge ROP. Uncheck random samples, and click the + sign to add a wedge parameter. Inside "channel" point it to the parameter on the CONTROL node you made in step 3. Set the range to be 0 to nprims("../path/to/REF_ALL_CURVES")+1 . This will keep it nice and procedural. 9. In the cache node, make sure to change the file name! Pick whatever directory you like, but make sure to add $WEDGENUM to it so it will write different sims! Here's an example of a path: $JOB/geo/magicdust/v001/magicdust_particles_v001_$WEDGENUM.$F4.bgeo.sc 10. On the wedge rop, hit "render wedges". Check the directory to make sure it's all working... 11. To bring them back in, just make a for each (number) loop in sops. Connect a file sop to it. There should be a 3rd node, the meta import node, which I usually rename to "m" for shortness. 12. In the file sop, construct the same filepath, but instead of $WEDGENUM, do the following: $JOB/geo/magicdust/v001/magicdust_particles_v001_`detail("../m", "iteration", 0)`.$F4.bgeo.sc This will load all your sims back in! Good luck! I hope I explained it okay.
  8. Animate parameter per cluster

    I think if your shot is laid out, and you know where the explosions are going to go, pre caching a few and either scattering or hand placing them ia the most flexible route. If you or your sup don't like a certain sim, it's easy to just swap in a new one or add more in certain places and rotate/scale them
  9. Animate parameter per cluster

    Hmm I see what you're saying. But would it be difficult to just sim 3 levels of detail? Like a lo/med/hi and assign that as an attribute to your instance points so it picks up the right foreground/midground/background sequences?
  10. Animate parameter per cluster

    I think a good approach for you would be to develop a sort of "master" sim that has the look of the explosion you want. Or, if they are to be drastically different, maybe 3-4 main sims. You could then run them as wedges, changing different "seed" parameters (like seed and offset in various noises, etc) to get different slightly different looks. If you name them like explosion_$WEDGENUM.$F4.bgeo.sc you'll get a set of explosion sequences. Then you can scatter some points, and give them some random rotations about their Y axis (just turning one explosion 90degrees can sometime give you as totally different looking explosion depending on the camera!) You can load the vdbs as a packed prim and use an "activation" or "index" attribute to say what frame you want to the explosion to start on, and set the unexpandedfilename intrinsic to load different frames on the points (see toadstorm's post for a better explanation at the bottom) Loading the caches in as delayed load VDBs will be quite efficient at rendertime, too.
  11. waterman

    First you could start by checking out Mixamo for dancing models. That part should be pretty easy to find online. The rest is pretty straight forward. If you're not sure of what to do, you should definitely start with the shelf tools. probably the "Emit Particle Fluid" one. The important part is going to be computing the velocity first though. Before you activate the shelf tool, lay down a "Trail" SOP and set it to "Compute Velocity". This will make sure that the interesting point velocities that you're getting from the dancing motion make it into the fluid. You can scale that effect by changing "scale source velocity" in the sourcevolume node in DOPS. The rest should be fiddling with some turbulence forces, gravity, drag etc to your liking. You can also use POPs in the Particle input of the solver and Gas nodes in the Gas input, since FLIP uses both.
  12. color gradient in extrusions

  13. Flip Splash - Grid Scale Optimisation

    Have you tried changing the grid scale to 4 to see if it has a big impact on the look of your sim?
  14. color gradient in extrusions

    Hi, Here's a solution. It's not super elegant but may work for what you're doing. extrude_for_elen_vou.hiplc
  15. Cave Ceiling Water Drop

    Check out 35mins in to see how they use surface tension to get droplets sort of like the one you're after