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Hi guys, here are the files I used for the last Vancouver Houdini User Group in case anyone wants to take a look. My presentation was about writing the Group SOP in VEX and trying to optimize it. I wrote everything in a wrangle, and it works great as a preset in a point/prim wrangle. I also made a Digital Asset, although it's not a VEX operator because I couldn't figure out how to make it work purely in VEX because I need to use the group bindings from the Wrangle and I'm not sure how to implement that in VEX. Anyways, the OTL is just the wrangle with the parameters promoted. In the presentation file you can take a look at the speed tests of the Group VEX vs the Group SOP. The difference in performance is pretty similar if you have a few points/prims, but once you go above 1 million the performance difference really starts to kick in. The Group VEX becomes exponentially faster than the Group SOP the more points you have. The difference can really be seen when you group by object and when you group by volume. I also made those 2 modes work with primitives. Here are the files in case anyone wants to take a look at the code. Feedback is greatly appreciated! group_vex_jeronimo_maggi.hipnc vhug_presentation_jeronimo_maggi.hipnc group_vex_jm.hdanc custom_group_sop.vfl

I hope to help you. when you import the abc , Please use the following. //------------------- AbcImport -rcs -mode import "D:/ball_test.abc"; //------------------- houdini_to_maya_vertexcolor_1.mb vertex_color_r01.hip

For C solution, i will copy detail attrib on a single point, use it as a point attrib in chopnet, then copy again to the original geometry. See attached screenshot.

Yo, not sure if you already found a solution but here's a quick set up that i made for a project a while back. It also allows you to offset the start frame of the sim too! Maybe someone smarter can clean up my expression. Right now it's using frames to ramp (since i was using baked sims), but you could easily adjust the expression for time as well. ODFORCE_TimeShifter.hiplc

hi Alvaro my main things to twiddle were the static threshold and scale kinetic. also the max acceleration in the solver tab is set to 50 by default - i dropped this down to about 10-15 for my scene - this seemed to restrain alot of the flying particles. Attached a super quick scene that i created with the dry sand shelf buttons. Sorry i dont really know much more mate :/ dry_sand_tweaked.hip

The time dependency is lost when HScript is backticked into a wrangle so this won't work for an animated channel?

You can get it with a Channel SOP, then use it in wrangler node. See attached file. VEX_CHOP.hip

A simple way is to just add a float value to your wrangle and then explicitly export from CHOPS to that float. then VEX can just read the local value directly. ap_vex read chop.hiplc

Made temperature greatest at the centers while also adding a "caldera width" parameter that prevents cooling near the eruption sight so that lava does not cool and clog itself. Timing and velocity not quite right.

Hey there, an easy way to get gradients on curves is to use fit with the point number with a max of npt (total number of points)-1, you can also use the uv texture node set to rows & columns which should produce a 0 to 1 u value gradient. In terms of lsystems, unless you are customizing it a great deal, I would turn to pops to create your lightning arcs. More control and organic behavior possible there. Here is an example of a 'Rolling lightning' test I did for a job way back when: For this I had 'arc points' scattered in the volume and a single particle would lead the direction of the arc. As it moved across the point cloud it would send out replicants that would try to connect nearby arc points as well as respect any custom forces (for example I wanted them to go from top to bottom, so they would do a point cloud lookup and get their desired target point then add in whatever custom downwards vector or noise I specified). If this seems like overkill then stick to lsystems, I just wanted to share the concept with you thinking maybe it would get some gears turning On another note there is a thread: here where a user put forth his space colonization otl that I could see also being very helpful in creating organic arc like shapes. Its a very similar process from what I did only its wrapped up nicely and fairly easy to understand if you take it node by node -N

Hi everyone! I have a moving camera projecting an image sequence on a fractured mesh. What I'd like to do is keep projecting each frame to each fractured part until they get activated. Finally, the active pieces should have projected the image from the last frame before activating. Do you know some way to implement this? Since uv's have to be projected before running the sim it hasn't occurred me how to do that. [Edit] I've managed to solve the problem. If someone face the same problem here is the solution I've found: 1- Project UV from camera before RBD 2- Run the sim 3- Import it with "transform input geometry" and plug in the original fractured geometry with the material (image sequence) applied. The uv's will remain the same but the material will keep updating seamlessly with the background. Cheers!

Two more explorations of the Shortest Walk growth. Again, rendered in Thea Render: And one growing roots: Cheers, Tom

And another one - based on the well known spider web tutorial by Tolya Shuverov. I added dew and a simple procedural spider with feet that always place themselves onto the closest thread... Cheers, Tom

Emmanuel, You could try the gap-filler otl I posted in this thread: http://forums.odforce.net/topic/18111-flip-smorganicsheeter-effect/page-6#entry145719 Some of the methodology/theory behind it is described in this paper: http://magnuswrenninge.com/content/pubs/ProductionVolumeRenderingSystems2011.pdf (Starts at page 157). This isn't a complete version, as described in the pdf, but a good base to start from (and the code isn't too complicated, either). This is done in sops but can easily be done as a point replicate procedural. -Adam

Ok it's probably 2 years late but here's a hip file based on the above rivulets setup. Sorry it took so long - I actually prepped this file back in 2014 to upload but could never figure out how to - but here it is. I still get constant requests for this setup or help with similar so it should still be useful. Note - it this example uses the old popnet method. But the vop stuff is still all good. SDF_voppop_particles_flow.hipnc