trails on alembic import

[xcaseyx]

Hello,

 

Im working on solving an effect right now, I can create the effect using a simple box, or any other parmetric geo inside houdini, but I can seem to get it to work with an alembic import. 

 

basically I want to have a range of trails emitting from the surface of an alembic import. I've attempted creating a vdb mesh, coverting, scattering points with a velocity attribute and then using the trail object, but I end up with this. 

 

http://d.pr/i/1ezzc

 

the same effect applied to a box or sphere would yield dynamic trails that have forces effecting the points, and inheriting the movement. 

 

any help would be appreciated. 

 

even when I get close, I get this. 

 

http://d.pr/i/GHUE

 

for some reason I cant get it to have a variable amount of roots per poly on surface area.

Edited September 10, 2015 by xcaseyx

[coolcoke33]

Hi,

 

I think because every frame is doing vdb mesh, so the geometry that u scattering points is changing every frame and so as points r changing.

 

I think you can try directly scatter on the alembic geometry, hope it would help

 

[xcaseyx]

oh hey thanks! turns out I was wildly over complicating it, 

 

http://d.pr/i/11Cvf

 

 

now just to delete points based on a noise field and call it a day! thanks for helping me cure my tunnel vision. 

[xcaseyx]

ok, so I have trails on my geo, working good, I spent some time finally reading the H14 documentation. wow so much changed from 12-14. 

 

so, now Im attempting to some dynamics to the trails, so that the points have particle turbulence, and motion inheritance from the mesh. 

 

 

the first part of this is doing basically what Im trying to do on the surface, but Im not sure if it will end up being a dynamic motion trail. 

 

 

This feels like something thats been solved many times in houdini, so wanted to pose the question to the forum. 

[Diego A Grimaldi]

Are you asking how to make a setup like the guy on the video?

[xcaseyx]

sort of, I mean for the most part I have the trails deforming with with some turbulence after wrangling and deleting some of the point + adding in a pointvop to add motion. 

 

I mainly want to have the trails be dynamic, similar to how hair would be, while still maintaining its length/velocity.

 

coming from cinema this task is next to impossible, unless you just use its hair system.

 

my current idea,

 

generate points on mesh using pointgenerate sop, delete to taste, add a trail sop, set length, use a pointvop to add a noise value to the points themselves?, reintroduce pops to connect the new particles?

 

still relatively new to houdini, its only been about 6 months, and primarily for fluids.  

 

http://d.pr/i/XOnN

Edited September 11, 2015 by xcaseyx

[Diego A Grimaldi]

You can use a particle network and using VDBs you can make it look more like a fluid...that's the idea behind the video you posted

[xcaseyx]

thanks I understand the principles of what is happening. That's not where Im having problems. 

 

also trailing on VDB is problematic, due the mesh shape changing and the fact that the vdb is happening ON frame, it make trails problematic. Again the what the video is portraying is simple, my concept is more difficult. 

 

import an animated mesh, generate points, trail on those points and have them react as if the velocity and motion of the mesh is effecting the motion of the points on the trails. 

 

wiggly, turbulent, lines are not hard to generate off the back of my mesh. 

[xcaseyx]

ok so I have things, inherently working. the streams begin to emit from the object correctly, then they get hit with some turbulence, then I delete points to keep the strand length desirable. 

 

currently having an issues keeping the streams themselves sticking to the point of emission. http://d.pr/i/1jzVH

 

as you can see the whole object sorta jiggles around. 

 

here are some shots of my script. 

 

http://d.pr/i/FvU9

 

and here is my file, if you have any animation source, you can just plug it into the alembic. 

 

http://d.pr/f/9rBG

Edited September 14, 2015 by xcaseyx

[xcaseyx]

I feel like I may be getting close but I can't seem to get the final ingredients working. 

 

the fade parameter I put in the pointvop seems to be behaving wierldy.