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Everything posted by woodenduck

  1. What is the best choice for soft bodies ? fem vs vellum

    FEM is for when you have all the time in the world. Vellum is for when you have to deliver. ;D
  2. My Vellum hair immediately shrinks in length when I try to sim it. I've tried stiffness and bend at outrageous settings. As well as constraint iterations up as far as 25000. Substeps, dampening, mass, thickness, changing restlength. Pretty much everything I can think of and it makes no difference at all to the simulation. It's like I'm not even changing any parameters. I've resampled all my hair curves to have 4, 8 and 12 segments. This also provides very little in the way of changes to the sim. Unfortunately I can't post a hip file. But if anyone has any suggestions I would be keen to hear them. Thanks, WD
  3. Vellum Hair shrinking

    Ha, typical! As soon as I post on OdForce I find the solution. So the "Rest Orientation Frame" parm on the Vellum Constraint Sop appears to have been the culprit. In my case this needed to be set to the start frame of the sim. Not the default F1. Cheers, WD
  4. No dop object specified ?

    Just need to change your expression from opinput() to opinputpath(). The first returns just the name of the operator. The second returns the path to that operator. This particular parameter requires a path.
  5. No dop object specified ?

    Can you post a hip file or screen shot?
  6. No dop object specified ?

    DOP network - can be a path. Object Mask - Should be just the name of the dopobject. Not a path.
  7. pop wrangle plugged in to "particle velocity" on the flip solver... v@v *= fit(@Frame, 1, 24, 0, 1); This will multiply your velocity on a ramp from 0-1 between frames 1 and 24.
  8. Maya to Houdini Camera wrong?

    if you attach a null to the camera at obj level and scale it to 0.1, does that line up?
  9. RBD concave thin wall collisions not detected

    So you cached the abc then you read it back in to render? Is the geometry packed? Do you have the same problem if you unpack followed by normal sop?
  10. RBD concave thin wall collisions not detected

    Glad you got it working, and of course whatever gets the job done is great. However, I would encourage you to investigate using convex hulls for all collisions. You will see vast improvements in speed and stability. They can be a little trickier to set up, but the rewards more than worth it.
  11. RBD concave thin wall collisions not detected

    The blue collision object you are visualising... is that created using a static object dop? If so, are you visualising the "Collisions/RBD solver/Volume" tab rather than "Collisions/Bullet Data" tab??? I think you may not be seeing what the solver is seeing.
  12. If 'v' exists on the incoming points, the flip object should pick that up automatically. So however you set 'v' in sops, should be what you see in dops. Otherwise, you can grab the 'v' and plug it in to the 'particle velocity' (inout 2) on the flip solver. pop wrangle. Inputs tab. Input1 = First context geometry. v@v = point(0, "v", @ptnum);
  13. Vex course

    I usually point anyone looking to get started with VEX at Matt Estela's excellent wiki... http://www.tokeru.com/cgwiki/index.php?title=HoudiniVex
  14. in a wrangle. Plug static points in to input1 and animated points in to input2 @P = point(1, "P", @ptnum);
  15. For Each attribute

    If you post a hip file, I'm sure someone will help you out.
  16. For Each attribute

    You can assign any attribute, id's or anything you like inside a foreach with any of the usual tools. Wrangle, attribute sop, vop sop etc... What exactly are you trying to do? Do you have an example of it not working? Cheers, WD
  17. Packed RBD from Pop Sim

    You can treat your packed rbds the same way you would a particle system. Setup your rbd network and plug your pop nodes in to the post solve (3rd input) of the Rigid Body Solver.
  18. RBD doesn't take all geometry only the first one

    You sim is only generating geo on the first frame. You can set "creation frame" on you rbdPackedObject node to $FF to get it to keep adding more spheres, however, it won't just add the new spheres, it will add a new instance of every sphere on each frame. At Sop level you will need to delete the spheres that have already been added to the sim at each timestep.
  19. Sop vex ptnum vs cvex

    Hi, So in days of old when you used to create a Sop Vex Geometry Type Operator you had access to ptnum as a read-only global variable. Now if I try that in a cvex operator I get "Error 1067: Reference to undefined variable: ptnum". What is the current method for getting the current point number in the cvex context? Cheers, WD
  20. reading string attribute value

    No problem
  21. reading string attribute value

    Two things... You typed "colour" when your attribute is called "colours" with an "s". Also, add the expression in the "group" parameter at the top, not the "filter expression".
  22. reading string attribute value

    I don't think you neeed the spaces or the quotes. Try: @colour=red
  23. Particle Advection (Simon Holmedal Effect)

    Take a look at these tutorials... https://www.sidefx.com/tutorials/particle-advection-tutorial-rendering-and-post-process-houdini-fusion/ https://www.sidefx.com/tutorials/millions-of-particles-h10-i/
  24. Ah, yes. If you have to use VEX, that's a solution. An attribcreate set to string with "objPath" in the name parameter, and opname("..") in the string parameter ,will get you the same result.