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Showing most liked content on 12/11/2019 in Posts

  1. 1 point
    Hi Dave! I just did some colored smoke, like last week. Sadly, it was a dumb straightforward solution. I'm sure there must be some clever way to extract the burn or heat fields, noise them up and then emit Cd from them. First I created my fire sim. Got it the way I liked. Then used the same source geo with some Cd noise and emitted colored smoke from that in another separate sim. Then I used the velocity field from the first sim. I figured that gave me the most control. I did use an offset noise from the fuel/burn/temperature emission in the original sim because otherwise the colors would be pretty bland as they would exactly correspond to the burning. The key in comp was to use the fire_mask from the original fire sim as the Cd will continue off far longer into space and not look like fire at all. However, I did find a sneaky little gotcha that chewed up a few hours of frustration. Do not, under any circumstances, add Cd to the Gas Resize Fluid Dynamic DOP in the Extra Resize Fields or the Reference Field. Why? From what I understand the internal blurring in the Cd field means that if it can it will greedily expand and take up more and more volume every step with minimal or no actual color value in it. You'll end up with a monster box. And not in a good way.
  2. 1 point
    Hi Mani, a common way to increase surface details on terrains is to use displacement maps on regular quad meshes. Texture haven and HDRI haven are good places for getting free texture sets without registration: https://texturehaven.com/ https://hdrihaven.com/ terrain_tex.hipnc
  3. 1 point
    Thanks HM - that solved the problem!
  4. 1 point
    Hi Jack, This should work: float @stiffness; int @group_inside; if(@group_inside==1) { @stiffness = 1; } else { @stiffness = 1000; } or in short: @stiffness = @group_inside==1?1:1000; Cheers, Luca
  5. 1 point
    while there are functions like inprimgroup() or inpointgroup(), whenever possible I like to use the shorthand @group_groupname syntax. So if you run over points and are looking for a pointgroup then your code would be if(@group_inside) { f@stiffness = 1; } else { f@stiffness = 1000; }
  6. 1 point
  7. 1 point
    Create a sticky note. Right-click and "Set Text Size" and "Hide Background".
  8. 1 point
    Here's a quick approach I came up with. It assumes all carriages are the same length. I also measure carriage length along the curve, rather than in world space, so it becomes more inaccurate the less straight the track. This should do fine for most purposes, but if I find the time I'll see if I can implement a more accurate measure. train_align_v001.hiplc
  9. 1 point
    while for triggering at various conditions you may need CHOPs or solver in your example you are simply playing back the animation at certain time intervals so for that you can just do this: float phase = chf("phase") / $FPS; f@bleep = chf("bleep", @Time % phase ); VexTriggeredAnimation_mod.hipnc
  10. 1 point
    Hi Daniel, that's a complex shape which will require a fair amount of RnD. But to get started you could delete the top of a spherified cube and deform it with noise. The finer surface structures would probably be done with displacement textures. cell.hipnc
  11. 1 point
    Hah, well why didn't you say that in the 1st place? The main problem is scatter messing up point counts. Here are 2 versions in this scene. Your way tweaked a little, and a copy points version. Switch the switch to 1 and reveal your instances to see your version tweaked. Copy points is another way that may allow more control with packed geo. Maybe someone will chime in with a completely better way to instance geo, POST sim, as its not good practice to rebuild every frame like this. _Example_Vellum_Scatter.HIM.v012.hiplc
  12. 1 point
    The issue here is not the velocity of flip but the velocity of the collision geometry which is very high ( too much). It's spinning really really fast, I can see values between -1100 and 600. You can see immediately this problem also in DOPs, enabling "Collision Velocity" under Guides. If you don't want to change the sphere animation, you can reduce the velocities by using a wrangle before OUT_COLLISION_POLY or in the collision tab reducing the velocity scale, which is basically the same thing. Here is the hipfile. Does this help? Issue with FLIP simulation.hiplc
  13. 1 point
    I know it's been a while but I ended up finding a solution through an older odforce post from vtrvtr. Basically you want to set a group of points in a "Pin to target" constraint and animate the breakthreshold attribute in sop. In order to transfer the attribute from sop to your ConstraintGeometry in dop, you need to plug a sop solver in your vellum solver. You will need to check "Invoke Compiled Block" on your sop solver node and add an extra output for the ConstraintGeometry. Inside the sop solver, you'll need to copy the breakthreshold attribute from sop to the ConstraintGeometry. Maybe there's another way, but it's the only way that worked for me so far! Thanks Vitor! fur_vellum_playblast_v01.mp4 test_fur_vellum_v04.hip
  14. 1 point
    Hey Kikohs, I'm not able to upload a file at the moment, but hopefully I can help anyways! First thing: your polyextrude is currently only extruding, but not creating a closed object. Make sure "Output Back" on the Extrusion tab is checked to have it create a closed object. VDBfrompolygons requires a closed object to correctly generate a VDB. Next, turn the Distance VDB back on in the vdbfrompolygons. Finally, in your vdbcombine clear the group fields as it will use the surface volume by default (which I believe is what you desire). Let me know if you have any other questions!
  15. 1 point
    I have no experience with this but I threw something together in 5min. Might work for you? surfaceTensionMask_dv.hipnc
  16. 1 point
    Hi, I hope this is the right place to post this. I'm working on an ice / snow shader for an iceberg cliff. I am a beginner, so the shader is still very simple, it's just a surface model and some displ noise. I've played with the SSS, refl and refract settings a bit, and tried my hands at some noise, but its still a looong way from looking realistic. I really hope you guys can help me with this! This is where I'm at right now (sorry for all the big pictures): wireframe (the model still needs some more work): network: And this is the look I'm actually going for (shader wise). The goal is hopefully to have a realistic looking iceberg shader. To help other beginners, it would be nice to have a hip file at the end, complete with notes and explainations, so everyone can learn from it. I'm including the scene file (without HDRI, it was too big), so definitely feel free to have a go at it! I hope you guys like the initiative and contribute some of your vast knowledge Iceshader_v001.zip Cheers!
  17. 1 point
    Here is a quick example I came up with. Using the Material SOP override mentioned above with local variables. Hope this helps. randomTextures.hip