Hello - Hopefully a quick question.
What's the best practise for copying to points and varying input parameters for each point?
It would seem this can be done via the Copy Stamp node but I’d also imagine this is quite easy via a For Each Point loop and using the 'iteration' number with a parameter to vary on each point. Is there a better, faster computation way?
edit - Just to clarify; i mean on the geometry side rather than the point attribute side, ie if i wanted to vary the amplitude of some noise on a sphere for each sphere copied to points
Thanks.
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Technical Discussion » Vary geometry copied to points
- Hatchery
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Houdini Indie and Apprentice » Modify Normal angle
- Hatchery
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If you know the points that need to be in the same directions will always sit above and below 0 in Z then this is as easier way as any but would probably need more info on how the points will be setup and distributed to figure out anything more procedural
Technical Discussion » INTEGRATED VELLUM SOLVER H19
- Hatchery
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Yes I’d also like to know the correct way to approach this.
See the attached file.. I've done it using a shapematch constraint on the wheel to fake an RBD, then pinned a centre point, and in this example use grains to cause the wheel to spin about the pinned constraint. BUT it really doesn’t feel like the way they did it in the launch video and I can’t then figure out how to stop the wheel going off axis (perhaps a collision object either side might?)
If anyone can offer any insight, then I’m sure the original poster and I would be grateful.
See the attached file.. I've done it using a shapematch constraint on the wheel to fake an RBD, then pinned a centre point, and in this example use grains to cause the wheel to spin about the pinned constraint. BUT it really doesn’t feel like the way they did it in the launch video and I can’t then figure out how to stop the wheel going off axis (perhaps a collision object either side might?)
If anyone can offer any insight, then I’m sure the original poster and I would be grateful.
Edited by Hatchery - Feb. 13, 2022 06:59:56
Houdini Indie and Apprentice » Change ColorAttribute of Object based on Particle Collision?
- Hatchery
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Here you go - much simpler.
Basic pop emitter and then a solver to work out if the particle point is within the radius of the sphere and colour it.
Also way faster based on sticking with a simple sphere and no need to loop over all those prims.
Basic pop emitter and then a solver to work out if the particle point is within the radius of the sphere and colour it.
Also way faster based on sticking with a simple sphere and no need to loop over all those prims.
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Houdini Indie and Apprentice » Normals are wrong after using the Sweep node
- Hatchery
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Not sure but could you use the dot product to just flip the ones in the wrong direction?
Drop down a wrangle, run over vertices:
Use the float channel slider to get the value that caputures them? Might not work as it might grab ones you dont want to flip, you could group just those around the problem area and then run it just over those points, looks like it might be okay
Drop down a wrangle, run over vertices:
float dist = dot(@N,{0,1,0}); if (dist > chf('val')) { @N = -@N; }
Use the float channel slider to get the value that caputures them? Might not work as it might grab ones you dont want to flip, you could group just those around the problem area and then run it just over those points, looks like it might be okay
Houdini Indie and Apprentice » How to get some points with surface oreintations?
- Hatchery
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Depends on exactly what you are after (having that second @up vector helps stop the orientation of pieces going crazy in animation, becuase it doesnt know which way is up) You can use Polyframe to calc the tangent and change it's name to up so you have an @up attribute.Can also work out the cross product between the normal and an second vector to get an @up
The only real difference will be how the pieces then orient on the copy. See attached file.
The only real difference will be how the pieces then orient on the copy. See attached file.
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Edited by Hatchery - Feb. 9, 2022 03:44:50
Houdini Indie and Apprentice » Change ColorAttribute of Object based on Particle Collision?
- Hatchery
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This is handy for a full list of built in attributes: https://mrkunz.com/blog/08_22_2018_VEX_Wrangle_Cheat_Sheet.html [mrkunz.com]
Houdini Indie and Apprentice » Change ColorAttribute of Object based on Particle Collision?
- Hatchery
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Yes, see _Alt file - you can change i@stopped to i@whatever but just need to update the name in the other wrangles and attribute delete node. Also the only problem with this is as the point passes through it stops being close enough to colour the sphere, if you wanted to maintain the colour then TBH its probably going to need to be redone done in a solver.
Or a quick and dirty meathod might be just to do a seperate copy of the pop net and use the point from that? Really depends what you need to happen and look like (also example attached)
Or a quick and dirty meathod might be just to do a seperate copy of the pop net and use the point from that? Really depends what you need to happen and look like (also example attached)
Edited by Hatchery - Feb. 5, 2022 07:43:29
Houdini Indie and Apprentice » Change ColorAttribute of Object based on Particle Collision?
- Hatchery
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TBH it could probably be done more efficantly as it gets a bit slow having to loop over all the primatives, but quite like these little puzzels every so often to practice :-)
Houdini Indie and Apprentice » Change ColorAttribute of Object based on Particle Collision?
- Hatchery
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Hello - Here is a quick vex solution also using a sop solver in the pop for the intial setup. Pretty sure there will be a simpler node setup up but im not sure how to do that.
Houdini Lounge » Multithreading Vellum
- Hatchery
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thanks and yeah i'd not fully appreciated how much of vellum was optimised for the GPU so deffo less value in upgrading to more cores on the CPU front.
Houdini Lounge » Geometry to Milk
- Hatchery
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I did something when playing with particles - https://www.instagram.com/p/CJibNLDH-O4/ [www.instagram.com]
Adapted from this:
https://www.youtube.com/watch?v=4mPHh-WzGZ4&list=PL0fCQcmH9FnOrcq4nbuUWSI8j_2NuAVpv&index=9 [www.youtube.com]
You might be able to adapt somthing with out having to resort to flip which can get a bit of a rabbit hole of settings.
Adapted from this:
https://www.youtube.com/watch?v=4mPHh-WzGZ4&list=PL0fCQcmH9FnOrcq4nbuUWSI8j_2NuAVpv&index=9 [www.youtube.com]
You might be able to adapt somthing with out having to resort to flip which can get a bit of a rabbit hole of settings.
Technical Discussion » Vellum Grains - Attach to Geo constraints
- Hatchery
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Technical Discussion » Vellum Grains - Attach to Geo constraints
- Hatchery
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Hello -
I'm trying to attach grains to a sphere as it passes thorough. However, using 'Attach to Geometry' in the solver is causing a great deal of swinging, no matter how high the constraint stiffness – see gif below. Id like the grains to stick much closer to where they hit (reducing the rest length doesn’t seem to help).
I can more or less eliminate the swing by using a pop wrangle and setting @v to zero each frame on the points that have stuck, but it seems like there is probably a better way to do what I want??
Test file also attached below if anyone has the time to help.
Many thanks.
I'm trying to attach grains to a sphere as it passes thorough. However, using 'Attach to Geometry' in the solver is causing a great deal of swinging, no matter how high the constraint stiffness – see gif below. Id like the grains to stick much closer to where they hit (reducing the rest length doesn’t seem to help).
I can more or less eliminate the swing by using a pop wrangle and setting @v to zero each frame on the points that have stuck, but it seems like there is probably a better way to do what I want??
Test file also attached below if anyone has the time to help.
Many thanks.
Image Not Found
Edited by Hatchery - Jan. 16, 2022 06:45:52
Houdini Lounge » Multithreading Vellum
- Hatchery
- 133 posts
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Hello -
Just out of curiosity does anyone know at what point more cores/threads starts to see diminshing returns?
i.e running a 12 core seems to utilise all cores (if not all fully utilised) with vellum, will this continue up to say a threadripper 32 core? Appreciate not all nodes are optimised for multithreading but vellum seems like it might be??
Thanks
Just out of curiosity does anyone know at what point more cores/threads starts to see diminshing returns?
i.e running a 12 core seems to utilise all cores (if not all fully utilised) with vellum, will this continue up to say a threadripper 32 core? Appreciate not all nodes are optimised for multithreading but vellum seems like it might be??
Thanks
Houdini Indie and Apprentice » How to access individual values of a vector attribute in VEX
- Hatchery
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try using @tangentu.x rather than .0
and maybe try v@tangentu.x to be very explicit its a vector.
and maybe try v@tangentu.x to be very explicit its a vector.
Houdini Indie and Apprentice » Snow compression
- Hatchery
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Try adding more jitter to the points before it sims, it was way more stable when I was playing with is and I didnt get that level of side displacement.
Houdini Indie and Apprentice » Snow compression
- Hatchery
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And here is a bit of an adaptation on how it could work with multiple compression objects like you'd need or footsteps.
Again feels quite hacky
Again feels quite hacky
Houdini Indie and Apprentice » Snow compression
- Hatchery
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Hello - See the attached as a starter-for-ten.
Ill just caveat by saying i'm pretty new to Vellum, so found this an interesting problem to have a crack at.
Whilst this works it does feel a bit hacky and so someone might be able to suggest a more elegant solution
Ill just caveat by saying i'm pretty new to Vellum, so found this an interesting problem to have a crack at.
Whilst this works it does feel a bit hacky and so someone might be able to suggest a more elegant solution
Edited by Hatchery - Jan. 4, 2022 12:47:57
Technical Discussion » Check a partial string value
- Hatchery
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