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About spectronaut

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    Patrick Loughman
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  1. This makes me think my approach is not possible. https://www.sidefx.com/forum/topic/42999/
  2. Obviously this loop will output points. The VEX for the wrangle "secondaryIntersect" seems valid, but I have no way of applying the attribute to the iteration pieces (primitives). VEX for "secondaryIntersect" running over primitives. vector p; vector hitprimuvw; vector srcpt; i@ptrefprim = prim(2, "refprim", 0); srcpt = v@P + (normalize(v@rdir)*2); i@hitprim = intersect(1, srcpt, v@rdir, p, hitprimuvw); if(@hitprim<5){ setprimattrib(2, "keepage", 0, 1, "set"); }
  3. I'll get right to it. I am running a foreach loop on a bunch of prims. For each prim I scatter a number of points. Still within the foreach loop, I run a point wrangle on those points. In the wrangle I run intersect on each of the points and if one hits I want to set an attribute on the prim (foreach loop peice) that the points were scattered on. In the end I don't need the scattered points, I just need the prims output with the attribute @keepage. What I cant figure out is how to set up the forloop so that this works.
  4. Yep works now, I knew about the vector length being trace distance (also realize in this example the vector was too short :p) BUT.... I was not aware of the v@derpyderp, good to know. Thank you much.
  5. heres a simplified hip file to illustrate my issue. How do I get the VEX to function like the raySop? rayVSintersect.hip
  6. I have a RaySOP that is doing exactly what I want. It is shooting rays per point along a direction defined by point attribute 'rdir' and is returning the hitprims I'd expect. Hitprims are the green numbers in the images below, yellow lines are visualisation of attribute 'rdir' (raySop shown below) I want to be better about doing things with VEX so I tried doing the same thing with the same set of points, with the same 'rdir' attribute and same collision geo. I get wildly different results for my hitprims as shown below. heres the tiny bit of VEX I've got: vector p; vector hitprimuvw; vector dir = @rdir; int hitted; hitted = intersect(1, @P, dir, p, hitprimuvw); @hitprim = hitted; What am I missing?
  7. Long story short, I have Prim_IDs written into a 32bit exr channel. I want to be able to delete geo primitives that do not show up in that EXR channel. I'm still a noob so any tips would be appreciated no matter how high level. Is it even possible to index all the render-present Prim_Ids and then translate them into an index that SOPs or VEX can operate on? Note: I had built a pretty cool set up that did traces from points on each primitive back back to the camera, but in order to avoid false positives and negatives without an absurd number of traces I thought the raster solution would be worth it.
  8. Thank you, again. So helpful. I am slowly getting the Houdini mindset thanks to excellent people like yourself. Very much appreciated.
  9. Is there a way to define a group of primitives based off the faces created by PolyCap?
  10. Thanks for the help duders.
  11. Yep. Exactly what I needed. Thank you, Atom. I'm a newb, so pardon my newbness. Could this method be achieved in a foreach subnet? Why would it be different?
  12. I have a bunch of hexoganol primitives. Each hexagon has a spine(curve) that I want to sweep the hexagon along. Each spine shares the same primnum as its associated hexagon. What is the best way to do this? What I've been playing with is a ForEach Loop that sweeps each hexprim along each spine.... but my results are confusing and bad. hexRox2.hip
  13. Excellent. Thank you kindly.
  14. I want to jack the streamer visualizations from my fluid source and use it to extrude shapes along. Is this doable? I want to do this because of how cleanly the streamer lines are distributed within a volume.