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Everything posted by bluciensky

  1. I've done upresing the smoke-only simulation, but never done the pyro(with fuel field). When I tried to upres my explosion simulation, I get the similar shape/motion as my low res one, but not the same density/heat/temperature. I would assume it's because gasupres DOP doesn't have the 'gas released' parameter, which would work with my source volume and affect the initial density/temperature/heat of it. What am I missing in this work flow?
  2. I have a float attribute called "test" that retuns 0-1 If I want to use that attribute value on the parameter on my wrangle, how do I write the expression? I tried point("/obj/test", @ptnum, "test", 0) This expression doesn't error out, but returns the value of point number '0'. If I write point("/obj/test", 3, "test", 0) then it returns the "test" value of point number 3, but it just that @ptnum doesn't work. What did I miss?
  3. Copy Sop Problem

    If you uncheck 'transform using template point attribute' on copy SOP, it will work, but I think that's not the result you want. This happens when you copy volumes(ex - 'vel' field will be messed up, so that you need to rotate it afterward).
  4. How to upres Explosion / Fire simulation?

    Thanks, Bunker, for your answer!! I realized I had some different valueson my Upres solver, after changing that, and tweaking a bit helped.
  5. How to upres Explosion / Fire simulation?

    Um, I can't post hipfile
  6. Shading problem

    could you post a hipfile?
  7. Can you post a hipfile that addresses the example(fluid) that you are talking about?
  8. dropdown pointsfromvolumeSOP under your vdbfrompolygonSOP.
  9. Time Shift Node

    Use 'File' node instead of Dop I/O. Select 'No geometry' under Missing Frame parameter.
  10. In the edit parameter interface for Ordered Menu -> Menu Type value on Token and the name for Label. For example, -.3 for Token and High for Label. After apply, Mouse over your dropdown menu(ordered list menu), right click, and choose 'copy parameter' then go to the parameter of translate Y, right click, 'Paste Copied Relative References'.
  11. Space shuttle exhaust -

    Make a field that has the vector information (curl shape), and use the field to advect the smoke - Gas Advect Field.
  12. This has happened before a few times. Let's say I have two geometry SOPs on obj level. I have only one of them turned on, and I am not viewing the other one(turned the blue visible mark off). When I scrub through timeline. It starts cooking the turned off geometry SOP. My quick fix is just putting Null SOP inside of the "supposed to be invisible geometry SOP". Is this a bug? * I am not rendering any images on Render View or anything.
  13. Flip Fluids Particle Dissipation

    I would! but I don't use houdini at home ever since it broke my Macbookpro graphic card once... and of course I can't post hipfile from work Sorry!
  14. Flip Fluids Particle Dissipation

    Use sopsolver or Geometry VOP to remove the points.

    I am not sure how do you mean by.. .region maybe black or empty? If you are just trying to render region, there's an option under camera parameter... something about 'crop' left, and right.
  16. you can also keyframe the timescale under Simulation tab. (considering all the shaping is set up...)
  17. CopySOP - copy the textures too?

    on your copy SOP, Attribute tab check Use template point attribute
  18. Rotate particle node gone?

    I normally do my instance using 'instancefile' attribute. Use atteibute create SOP. Attribute name. instancefile Class. Point And this is string attribute. Then put that expressions in the parameter. Check Geometry spreadsheet to make sure you have the instancfile attribute path randomly assigned. For your case you want to use. int(fit01(rand($ID),1,5)) (I think that gives you the int value from 1-4 or something... Otherwise just changing the range to see). If your geo path doesnt have the incremental pattern, you may just do this using attribute Vop using switch node or sth. Now. On Obj level. Add. Whole 'instance' tab from edit parameter. (Or maybe you can do this from self menu. It's hard to explain this without having a computer with me lol). This enable the instancefile attribute to work as an instance.
  19. Rotate particle node gone?

    Assign orient attribute for the rotation. Also, how are you instancing it? If you are using the 'instancefile' attribute for the instancing, you may just have four different attributes path (randomly assigned) pointing to four different geos. I don't have a computer, so no hipfile... But keywords you can search are Point + Orient. Upvector. Velocity. Instancefile.
  20. As I am working with heavy geo, I want to keep my houdini session as 'Manual'. Although it would be convenient if there was a shortcut instead of clicking the two arrows to cook it. I've found a script that toggle between auto update/manual mode, but that's not what I am looking for. I've seen a person who's doing this with shortcut with a script. How do I set this up? Thank you!!
  21. Ah! my colleague also told that I can just easily assign it from houdini edit -> hotkeys. I didn't realize it has the option there already for 'force update'. Works wonderfully......
  22. Thanks, John!! I will try that.
  23. There are multiple ways of doing it. How does your source looks like? let's say you have a moving object with point velocity(if you don't, just put down 'trail' to make). Drop down vdb from polygons (or vdb from particles, if your source is from points or something) and check 'fog VDB(density), and add Attribute 'point.v' below. Make your VDB name 'vel', and now if you MMB on 'VDB from Polygon' sop, you will see 'density and vel. This vel fields should have the initial velocity. To check if the vel fields's working. Put down Scatter SOP under your VDBfromPolygon. Then put down volumetrail SOP. Plug the scatter on first input, and your volume from VDBfromPolygon onto the second input. Type 'vel' on Velocity Volumes parameter. And you will see that the trail looks like your velocity. In the DOP network, in Source Volume. Put '100' on Scale Velocity parameter to test if that's working. If it works fine, you can just find a good value for your simulation. Well, this is a rough explanation and just one of the methods...! so yea, there are other ways to do that as well. or you can just put your own velocity value that is similar to your moving object using volume vop or something
  24. Do you want your pyro simulation to be affected by the object's velocity? - then just use the moving object as collision geo (static object with transform checked), this would be easiest way... or you want your source volume for your simulation to already have the initial velocity from the moving object? - add velocity fields that has the velocity of the moving object, and use it for your simulation.
  25. You want to make it as an attribute. For example, make an attribute called 'velzero' whatever the length of 0 is red (1,0,0) otherwise blue (0,0,1). You do this on SOP (or shader... up to you) Have this attribute on your shader(using bind, and export it), then put the attribute name on your AOV VEX Variable and channel name(this can be different name).