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mestela

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Everything posted by mestela

  1. Noise never decreasing in VEX

    Or this trick from Matt Ebb that doesn't require a solver: http://www.tokeru.com/cgwiki/index.php?title=Houdini_Vops#Noise_that_always_increases_with_cellnoise_vop
  2. WIP - ok++'s softbodies RnD + .hip files

    Did I say thank you already? I'll say it again anyway, thank you! Some incredible stuff here, can't wait to get some free time and pull these setups apart...
  3. More Particles Following a PATH!

    Something like this? I'm dumb and would need to see the geo of the spiral curve, but I'm sure the logic within here could be used to generate a spiralling force directly in pops. coil.hip
  4. More Particles Following a PATH!

    Also, a japanese houdini user wrote a great tutorial about a better pop curve force setup; google translate does a pretty good job, but you can also just grab the hips linked at the end of the article: https://qiita.com/taikomatsu/items/71d475541eb540705552
  5. More Particles Following a PATH!

    It should do that by default; if you have @v (and not @N or @orient), when you use a cop sop to copy geo to the particles, they should point their z axis along v. http://www.sidefx.com/docs/houdini/copy/instanceattrs.html Examples and gifs and stuff here:
  6. difference between @Cd.r and $CR

    And that's another fun gotcha with houdini; if something is designed to read attributes directly (like the scatter sop is), you don't use the @ prefix. That also means that it won't understand the thing.subthing syntax, so Cd.r won't work either. Put down a point wrangle before the scatter, and create a new attribute which is just the red component, we'll call it red: @red = @Cd.r; Now in the scatter you can put 'red' into the density attribute field. It'll make sense in time, honestly!
  7. difference between @Cd.r and $CR

    Dollar variables are hscript expression variables, hscript is sloooowly being phased out. At-symbols are vex attributes (@-ttributes, get it?), they're becoming the standard way to refer to geometry properties through most of houdini, its better to get used to that syntax. Occasionally you'll find some older nodes that only work with the older dollar syntax, best to ask here if you stumble across those. -matt
  8. Shrinking Pieces inside of DOPS

    The answer here was clashing names; the sops feeding into a pop source used to drive the rbd sim had static names, meaning when multiple copies of things all had the same name, and wrangles and whatnot were trying to update prim info, the system would get confused. Adding the current frame to the names in sops ensured everything had unique names (well, unique enough), kept it all under control. (assuming this is the same problem posted on discord, if not I can post the example scene we came up with)
  9. Help With Speeding Up Render

    Nice work Toby!
  10. Learning VEX via Animated Gifs - Bees & Bombs

    More inspiration: https://necessarydisorder.wordpress.com/2017/11/15/drawing-from-noise-and-then-making-animated-loopy-gifs-from-there/
  11. Came across these great looping gifs yesterday, all done by David Whyte mostly in Processing. http://beesandbombs.tumblr.com/ All looked like fun things try in Vops/Wrangles, thought others might want to join in. Picked this one to start with, attached is my attempt with a point wrangle ( H15 ). http://beesandbombs.tumblr.com/post/107347223679/columns bees_and_bombs_columns.hipnc
  12. sine / cosine on circle?

    Or this sorta thing? icecream.hip
  13. Solver sop. http://www.tokeru.com/cgwiki/index.php?title=The_solver_sop#Attributes_other_than_position
  14. Constraints mixing pops and bullet

    I had a go at tidying it up based on what I've learned in the past month; not sure if I've missed the point of what you're trying to do though! I removed all the pop stuff and things that didn't seem necessary, all the constriant weirdness you were getting is stuff I was also getting at first; mostly it comes down to controlling whats animated and whats not; rbd object inputs should be static, and the end of the constraint polyline connected to the rbd object should also be static. Anyway, here's my file: constraintProblemsTest_me.hiplc all my notes on this stuff are here: http://www.tokeru.com/cgwiki/index.php?title=ConstraintNetworks http://www.tokeru.com/cgwiki/index.php?title=ConstraintNetworks2 -matt
  15. Smoke Solver | Tips and Tricks

    Really cool, thanks for sharing.
  16. There's clever ways to rotate in place (which I always forget), but just about everyone I know does the simple thing of move stuff to the origin, rotate, put back to the original position. To make your setup work, I just added an extra wrangle before the copy to points to store the point position, as centroid: v@centroid=@P; Then in the rotate wrangle, subtract centroid, rotate, add centroid: matrix3 m = ident(); float angle = ch("angle"); vector axis = normalize(v@rot_axis); rotate(m, angle, axis); @P-=v@centroid; @P *= m; @P+=v@centroid; matrices_me.hipnc -matt
  17. Particles along surface

    There already was a section, I've been cribbing from my own notes to contribute to this thread. http://www.tokeru.com/cgwiki/index.php?title=HoudiniDops#Pop_stick_to_surface
  18. Particles along surface

    How accurate do you need to be? Point deform works well if your standards are low (and still works pretty well if your standards are higher than that, within reason) pop_minpos_align_pig_pointdeform.hipnc
  19. Particles along surface

    Less lazy attempt: pop_minpos_align_pig.hipnc
  20. Particles along surface

    Heh, I was taking at dig at my lazy self, not your question. You're right, pushing along @N should work, curious that it doesn't. It was more to do with how the sprite display sits right on the surface, so they'd clip, this was a cheap fix. If this were a Proper Solution, I'd instance real geo that was properly offset away from the origin along z, so they roll along the surface, or use a peaked version of the geo for the sim, and non-peaked for the merge at the end.
  21. Particles along surface

    minpos is my new favourite lazy way. pop_minpos.hipnc
  22. VEX 101 and new point SOP

    Definitely vex over python when starting; python is handy for pipeline stuff, interfacing to other apps, best to delay that until you need it. Usual plug for my wiki notes here: http://www.tokeru.com/cgwiki/?title=HoudiniVex
  23. VEX 101 and new point SOP

    $BBY equivalent as per your post: vector bb = relpointbbox(0,@P); @Cd = set(bb.y,0,0); You can't delete attributes in a wrangle, you'd use an attribute delete sop. It's all more verbose than before, but scales much better, and is more internally consistent.
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