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Everything posted by woodenduck

  1. Access sop parameter within popnet ?

    You can use a channel expression - ch("../../path/to/parameter")
  2. Take a look at this - http://tmdag.com/vopraytracer-pt1/
  3. You can resume simulation from .sim sequence.
  4. Particles won't emit (H15.x)

    Go inside your popnet, on the popSource node, inherit attributes parameter. By default this should be set to '*' but on yours it is empty. Just pop a '*' in there and you're good to go.
  5. extra tokens in expression

    Try separating with "" and + so your expression would become... ch("../../../img/comp1/default_pic_"+opdigits(".")+"/size1")/200
  6. Pyro velocity field question

    You could add a GasFieldWrangle piped in to velocity update with @vel *= 0.9; in the vex snippet parameter. You could add a gasFieldVop piped in to velocity update. Bring the vel field in with a Bind Vop and multiply 0.9 (or whatever drag rate you want) before adding a bind export set to vel. You could add a gasDamp Dop. This would also get piped in to the velocity update input on the pyro solver. You could also try playing with the viscosity parameter. This has the effect of blurring out the vel field which will give you a kind of drag. Depending on what you are trying to achieve.
  7. emit particles from pyro sim

    You can use a Scatter Sop on a density field, then source you particles from there.
  8. Using Bend in Houdini

    lay down a 'transform' sop. Hit tab and start typing transform. From here you can move you tube where you want. Then lay down a 'merge' sop. Plug the output of the transform AND the output of the node BEFORE the transform in to the merge. You should now have two tubes in different positions.
  9. Using Bend in Houdini

    Start with a curve. Click the curve tool from the 'create' tab at the top. Then click in the viewport to start creating a curve. Once you have something close to the shape you want (you can push and pull the individual points around by clicking on them and hitting 't') you can then append a 'polywire' operator to your curve. This will create a tube based on the shape of the curve you use as an input. You can increase the 'segments' and 'divisions' parameters to get a smoother tube. Enjoy!
  10. You can bring vel in to a volume vop using a 'bind' vop. Name = vel, type = vector. Do whatever operations you want on it then you can use 'bind export', again set to name = vel and type = vector.
  11. POP inherit point normal from passing a point

    You will need to set the 'radius' and 'maxpoints' channels to something useful... ;D
  12. POP inherit point normal from passing a point

    Try this in a popwrangle inside the popnet. if(@n2 == 0) { float radius = chf("radius"); int maxpts = chi("maxpts"); int handle = pcopen(1, "P", @P, radius, maxpts); v@n2 = pcfilter(handle, "N"); v@N = @n2; }
  13. magnet point snap align

    Is your geometry packed?
  14. attrib wrangle set to run over prims... addpoint(0, @P); removeprim(0, @primnum, 1);
  15. Need advice from Houdini users.

    In my experience, the best way to revise your math is to use Houdini ;D
  16. staggering a carve by primnum

    Hit "create meta import node" on "foreach begin" to allow access to the iteration attribute. Then add the following in to the second u parameter of the carve sop: clamp((1-$T)+(detail("../foreach_begin1_metadata1/", "iteration", 0)/2), 0, 1) Should be good, providing your metadata node is named the same.
  17. Is this in a Wrangle? Has forcescale been declared anywhere?
  18. VDB Cloud

    On the top right of your viewport above where you select your camera, there is a drop-down menu. You can choose how all geometry is displayed. Set to "shaded bounding box". If you wan to control the display per-object, you could use a "bound" sop and set the blue display flag on, while keeping the purple render flag set to the original geo.
  19. Viewport xform Python expression

    Hi, I have created a geo node who's world transforms are matched to those of the current viewport, using the following Python. import toolutils viewer = toolutils.sceneViewer() viewport = viewer.curViewport() xform = viewport.viewTransform() obj = hou.node("/obj").createNode("geo") obj.setWorldTransform(xform) So far so good... Now I want to set these values with Python parameter expressions on the object so that the transforms are updated when the viewport is tumbled. The problem I'm facing is when I try to access the individual components of the xform matrix to set as the object parm I get "the Matrix4 object is not iterable"...??? Any ideas how I can dynamically link an objects transforms to those of the viewport? Thanks for any tips, WD
  20. Viewport xform Python expression

    Thanks @cosku, This is exactly what I was looking for. Cheers! WD
  21. Lots of balls!

    Nice balls, Rafael!
  22. Pre-Roll Pyro Sim

    Cache with an extra 25 frames (from F25 to F83) then timeshift the cache post sim. After your file node that reads the cache from disk, add a Timeshift with an expression in the Frame parameter set to $FF+25.
  23. Have you tried casting @ptnum and @numpt to floats before dividing? (float)@ptnum / (float)@numpt I think VEX will treat them as integers and not divide correctly otherwise.
  24. rbd strange behavior with flip fluid

    I would first check for interpenetrating geometry. MAybe try reducing the penetration threshold on the bullet solver. Are you by any chance using a drag dop in the glass simulation? I had something similar where the drag node caused my bullet sim to go haywire. You could also try whacking the substeps on the solver.