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Found 16 results

  1. Advice needed for pyro sim

    Hi Guys, I am currently working on a shot where I need to simulate an object falling slowly through deep water whilst bleeding (The more blood the better). Initially I began with a pretty simple setup, An emissive object, a collision object and a divergence volume which is being used for expansion. The problem I am running into is that I need the smoke to continually expand, whilst becoming more diffused and transparent, but to always remain in the sim. So I have disabled dissipation as I don't want to lose density, but this leaves me with a dense volume which isn't transparent or diffused. I would like the density that is in the sim to have an aged based blurring. I did try to achieve this with a gas dissipate and heat field but this still wasn't right. I have also spent time trying to tweak the pyro shader to achieve the desired effect but I am not having much luck. I also need to preroll this sim by 400 frames, which means it's taking time to view changes I make in the sim. If anyone has any workflow tips that would be awesome. Below is an example of the look I am trying to achieve. Between 0:21 and 0:34 Any advice will be greatly appreciated. Many thanks, Clive Blood_in_water_odforce.hip
  2. Hi folks, which node can set texel density to UVs? And why are all the polygons are separated in the UVs? I tried to use Fuse UV but that's not solved it. Maybe I missed something I'm newbie to Houdini :]
  3. paint density

    hi guys i use paint node to get particular scatter points for my object but when i fracture it, pieces look so long i guess it is a density problem. i just want irregular pieces but more points in some areas.how can i fix it.please help me... test.hipnc
  4. Change Density of Flames Pyro

    Hi, How can I adjust the density of the flames in a pyro render? Right now, I have smokeless flames, and the flames are not dense enough. You know how you can change the density of the smoke? Cant you do the same thing for the flames? In visualization of the smoke object, I can make the flames appear more dense in the viewport by going to pyro's visualization go to emission then scale it up. You can see the results below. How can I do that in the shader, though? The flames are just to thin and transparent. The only thing I see is the fire intensity scale, but it makes it brighter not more dense. Any suggestions? Thanks
  5. Volume density from texture?

    Hello magicians, I saw a great image by Lee Griggs the other day and I tried to replicate, here is the original effect He did it with Arnold (i think in maya), by projecting a texture into a volume density, here is some explanation https://support.solidangle.com/pages/viewpage.action?pageId=55710284 I didnt know how to project a texture into density, so I projected a texture, the deleted by color and converted that into vdb > fog, but that way I don't get any depth, any ideas? I've read about a rest field that does something like UV on volumes but cant figure out how Here are my attempts: Hip file attached, Cheers! volnoise3.hip
  6. Hello,I have 2 questions about the hair:1. When I paint the density attribute the hair guides are reacting based on the vertices, i.e. when I hit only a vertex guides disappear (or appear). It means that with low polygon count I can't avoid stepped guides boundary. But with more subdivisions it is practically impossible to work due to long cooktime after each brush stroke… How can I deal with the guides between the vertices without increasing subdivision? Attachment below describes it.2. To delete hair guides (for example, for hairline or beardline on the head) I use Length Adjust shelf tool with Target Length value of 0.001 (complete 0 is impossible), but this still leaves hairs roots as dots when rendered. Is there a cleaner way to delete the hair neatly along the boundary?
  7. Exploding RBD's in FLIP fluid

    Hi Guys, I need some expert advice and insights on this project I'm working on. I'm doing some RnD first before moving to bigger scale so I can provide you guys with the HIP file. The objects however (barrels and table pieces) I cannot share with you. But maybe there's something in the dop nodes or solvers that you can spot right away. I'm working on a flood scene where there's a lot of debris and rubble that needs to be transported by the water. Please have a look at the video. The barrels seems to acquire a spin which at one point is out of control! I can imagine this could be the rotational stiffness... but the exploding (and stuck) piece of table is still a mystery at the moment. As you can see I'm also having trouble controlling the buoyancy of the objects in the fluid. Right now I use the density to try and float pieces but it's not entirely working the way I want it. To sum it up: - The wooden planks need to float - barrels need less spin and need to be embedded more in the fluid. - the tables obviously need to stop launching like superman . any advice or tips are greatly appreciated . High-RBD_count-in-fluid-006.hip
  8. Would it be possible to have a sphere primitive or any geometry affect the density of a volume (fade density from 0 to 1) based on distance between the geometry's pivot (or all points) and the volume?
  9. Pyro Attributes

    Hello! I'm encountering a little problem with Pyro Fx. When I export a geo file from any fire, the attributes of heat, temperature and fuel look good in the viewport but when I render them, I get a particles cube. It seems that those attributes are not exported in my bgeo files (I tried with Vdb files and got the same result). Is it a bug or is there a step that I missed in the export? Thank you!
  10. Smoke Density Driven By Velocity

    Hello! I was working on a basic smoke sim where the smoke was being emitted from animated type-geo. I computed the velocity of the geo with a trail, then plugged that into the fluid source to create the density for the smoke sim. That is all working fine as you can see in the render. However, I'm not happy with how the smoke just appears all at once. In other sims I've used an attribute wrangle to map the density to a ramp and have the density fade in but in this case I want the smoke density only to be generated when the velocity starts to increase. I played around with trying to get the velocity data out of VOPs but I really was just taking stabs in the dark. Any suggestions would be appreciated. smoke_test_v02.mp4 text.abc smoke_density_v01b (1).hipnc
  11. One simulation 2 densities

    Hello, I'm doing an exercise of the launch of two smoke grenades . My problem arises when once made the simulation I want to save each smoke in a different file to give different shaders . I cant do it because both smokes are in the same "smokeobject1". Each smoke interact with each other. Thanks!
  12. Hi guys, i am struggling with stupid problem, i want to convert my bgeo files to VDB to later render them with arnold. But on convertvdb node i have that density channel is <empty>. I don't know what is wrong with my scene, for test i created same setup flames from the shelf, didn't change anything and it's working. Do you guys have any suggestion? Thanks firenosmoke_v003.hip
  13. I've been getting back into FLIP, and trying to replicate this test done in Naiad a while ago: https://vimeo.com/25020677 Using some POP nodes, I know I'm getting attributes changed on the points properly, but I can't figure out why the solver isn't pulling the higher density particles down under the lower density ones. I even played with @mass, hoping that'd do it, but it doesn't. The POP nodes are affecting the points just fine; when I crank up viscosity/velocity/color, those are set properly. The red points should be rising up, and the teal/blue ones should be sinking since they're heavier: Does anyone have some insight(s) as to why the density isn't making points rise/fall? Thanks! dense_flip_separation.hipnc
  14. Lines in the centre of Mesh

    I'm trying to create lines in the centre of an object. So I guess the theory is that I need to calculate the density of the object and then create points at the centre of the object that can be connected with a add sop? Here's what I have so far (no VOPSOP added yet) Any ideas? MeshtoLines.hipnc
  15. Density to Opacity Node

    Hows the DensitytoOpacity node used and why is there always an error when i try to use it? the example file is not very helpful.
  16. multiply collision with density

    Hi everyone I'm using a smoke simulation where a simple source is dripping smoke on a collision box. The collision uses the sourcevolume method, so I have the SDF collision available. I'd like to create an additional field which is nothing else than the result between the multiplication (intersection) between the collision field (after gassdftofog) and the density field. Basically I'd like to use this resulting field into a pyro symulation (a separated sim) as fuel to emit fire. The result would be that some fire emits from the locations of the cube where the smoke is dripping. I used a match field to fill a field "collisioncopy" scalar field, and filling it with the content of the collision sdf after converting it to fog. Then I used a gaslinearcombination with the folliwing calculation collisioncopy=collisioncopy*density The problem i have is that obviously the collision field and the density field are mutually excusive so the result is an empty field. My question is: is there some quick and dirty way to "expand" a certain field by a certain amount of voxels (in the direction of the gradient of its density for instance). This way i would be able to have an overlapping area between my collision field and the density and I could calculate the intersection between them.
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