hello,
I was wondering how to group flip fluid particles based on an initial collision with static objects in DOPS? I only want the group to contain the particles which have just collided. Any ideas?
thanks,
Adam
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Houdini Indie and Apprentice » grouping flip fluid particles based on initial collision
- gaileyag
- 14 posts
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Houdini Indie and Apprentice » expressions to control particle opactiy
- gaileyag
- 14 posts
- Offline
Hello,
I have created a particle system and have copy stamped a primitive sphere onto each of its points. I have chosen to allow point attributes to affect the spheres. This allows me to get varying opacity on each sphere as I have used a rand($ID) expression in the lookup parameter of the alpha ramp tab of the color POP in my particle network.
I was wondering if someone might be able to help me with an expression that could not only create a random opacity for each point but also fade that random value down to zero over the course of the particles life…
It thought of using a rand in conjunction with a fit but I cant get anything to work very well. any suggestions?
Thanks very much in advance,
Adam
I have created a particle system and have copy stamped a primitive sphere onto each of its points. I have chosen to allow point attributes to affect the spheres. This allows me to get varying opacity on each sphere as I have used a rand($ID) expression in the lookup parameter of the alpha ramp tab of the color POP in my particle network.
I was wondering if someone might be able to help me with an expression that could not only create a random opacity for each point but also fade that random value down to zero over the course of the particles life…
It thought of using a rand in conjunction with a fit but I cant get anything to work very well. any suggestions?
Thanks very much in advance,
Adam
Houdini Indie and Apprentice » manipulating constraints in a wire simulation
- gaileyag
- 14 posts
- Offline
Hello,
I would like to constrain a RBD object to one of the wires in the attached simulation. I have tried using several different kinds of constraints but nothing really does what I want. I simply want to add an object to the end of one of the wires that will act as a weight and affect the movement of the wire.
Also, is there a way to attach the constraints to a point on a piece of geometry rather than an arbitrary point in space? Really enjoy working with wires in Houdini but need a bit of help to take things to the next level.
Thanks in advance for any tips or advice.
Adam
I would like to constrain a RBD object to one of the wires in the attached simulation. I have tried using several different kinds of constraints but nothing really does what I want. I simply want to add an object to the end of one of the wires that will act as a weight and affect the movement of the wire.
Also, is there a way to attach the constraints to a point on a piece of geometry rather than an arbitrary point in space? Really enjoy working with wires in Houdini but need a bit of help to take things to the next level.
Thanks in advance for any tips or advice.
Adam
Houdini Indie and Apprentice » rsmb velocity pass for particles
- gaileyag
- 14 posts
- Offline
hello,
I have created a particle effect that I would like to obtain a velocity pass for. I have set up a particle velocity take and I am using the rsmb.otl shader that is available from the exchange to get the vectors.
It works great for animated scene geometry but I cant seem to get much results when applying it to a particle system. I think it might be an issue of tolerance?
what is a good tolerance for the rsmb shader when dealing with quickly moving particles? Is there some better way to obtain this velocity info for my particles?
thanks for any help you may be able to provide
Adam
I have created a particle effect that I would like to obtain a velocity pass for. I have set up a particle velocity take and I am using the rsmb.otl shader that is available from the exchange to get the vectors.
It works great for animated scene geometry but I cant seem to get much results when applying it to a particle system. I think it might be an issue of tolerance?
what is a good tolerance for the rsmb shader when dealing with quickly moving particles? Is there some better way to obtain this velocity info for my particles?
thanks for any help you may be able to provide
Adam
Houdini Indie and Apprentice » How to export GI pass as a image plane
- gaileyag
- 14 posts
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Houdini Indie and Apprentice » How to export GI pass as a image plane
- gaileyag
- 14 posts
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Hello,
I have set up a light template that has a VEX Global illumination shader assigned. When I go to render in mantra I get an excellent image but I don't know how to isolate just the global illumination into a separate image plane for compositing.
For instance I can get the specular pass by creating an image plane and specifying specularExport - what do you have to specify to get just the Global Illumination?
am I ovelooking something?
Thanks in advance for any help you might be able to provide.
Adam
I have set up a light template that has a VEX Global illumination shader assigned. When I go to render in mantra I get an excellent image but I don't know how to isolate just the global illumination into a separate image plane for compositing.
For instance I can get the specular pass by creating an image plane and specifying specularExport - what do you have to specify to get just the Global Illumination?
am I ovelooking something?
Thanks in advance for any help you might be able to provide.
Adam
Houdini Indie and Apprentice » all polygonal geometry is black in the viewport?
- gaileyag
- 14 posts
- Offline
Thanks Simon! That is indeed a strange way for the merge sop to behave but at least its a very easy fix once you aware of what is happening.
Thanks again for the tips!
Adam
Thanks again for the tips!
Adam
Houdini Indie and Apprentice » all polygonal geometry is black in the viewport?
- gaileyag
- 14 posts
- Offline
solved!
THe merge sop was doing something odd with the attributes created by the facet sop higher in the tree. I just disabled the facet and everything came back.
Sorry to bother with the post.
Adam
THe merge sop was doing something odd with the attributes created by the facet sop higher in the tree. I just disabled the facet and everything came back.
Sorry to bother with the post.
Adam
Houdini Indie and Apprentice » all polygonal geometry is black in the viewport?
- gaileyag
- 14 posts
- Offline
hi again,
I think this had to do with the merge sop. I think it did something strange with the normal attributes of the polygonal geometry. If this is the issue I think I might be on the right path to correcting things. We shall see.
I think this had to do with the merge sop. I think it did something strange with the normal attributes of the polygonal geometry. If this is the issue I think I might be on the right path to correcting things. We shall see.
Houdini Indie and Apprentice » all polygonal geometry is black in the viewport?
- gaileyag
- 14 posts
- Offline
hello,
whenever I cut on my display smooth shaded or smooth wire shaded all of my polygonal geometry in the viewport goes black. All primitives are visible though.
is there some setting that I may have accidentally changed?
thanks,
Adam
whenever I cut on my display smooth shaded or smooth wire shaded all of my polygonal geometry in the viewport goes black. All primitives are visible though.
is there some setting that I may have accidentally changed?
thanks,
Adam
Technical Discussion » color diffusion using voxels?
- gaileyag
- 14 posts
- Offline
Technical Discussion » color diffusion using voxels?
- gaileyag
- 14 posts
- Offline
hello,
I am having a very difficult time trying to diffuse the colors of fluids. Does anyone know of a method to blend/diffuse colors when using volume fluids?
I have already looked at the tutorials for blending colors using particle based fluids. Is there a similar method when using voxels?
thanks is advance,
Adam
I am having a very difficult time trying to diffuse the colors of fluids. Does anyone know of a method to blend/diffuse colors when using volume fluids?
I have already looked at the tutorials for blending colors using particle based fluids. Is there a similar method when using voxels?
thanks is advance,
Adam
Technical Discussion » retaining color diffusion when applying default shaders
- gaileyag
- 14 posts
- Offline
hello,
I am a newbie to fluids in Houdini and I keep running into issues.
Perhaps this is a simpler question than the last one I posted…hopefully
I have used a gas diffuse node to blend the colors of two fluids in a simulation. When I apply the basic liquid shader to the particle fluid surface I lose the color information and diffusion but the look of the liquid is much nicer.
Is there anyway I can retain the color and diffusion established in the DOP network and still have the nice refraction and reflection created by the basic liquid shader?
Of course Ill keep trying to figure this out on my own but any guidance or pointers would be much appreciated
Thank you,
Adam
I am a newbie to fluids in Houdini and I keep running into issues.
Perhaps this is a simpler question than the last one I posted…hopefully
I have used a gas diffuse node to blend the colors of two fluids in a simulation. When I apply the basic liquid shader to the particle fluid surface I lose the color information and diffusion but the look of the liquid is much nicer.
Is there anyway I can retain the color and diffusion established in the DOP network and still have the nice refraction and reflection created by the basic liquid shader?
Of course Ill keep trying to figure this out on my own but any guidance or pointers would be much appreciated
Thank you,
Adam
Technical Discussion » fluids - problems with emission
- gaileyag
- 14 posts
- Offline
Hello,
I have been trying to get this to work for me for a couple days now and I have seriously come to a wall. I've tapped out every resource I have other than this one in order to find the answer. If anyone can take a look at this file and help me out it would be truly amazing and I would be very thankful indeed!
WHAT I HAVE DONE:
I am trying to use a gas diffuse node to blend the colors of the fluid particles being emitted from two separate emitters. The first emitter is a polygon sphere using impulse activation and impulse birth rate. The second emitter is a default emitter using stream activation.
I have appended a color attribute to the POP networks inside of each of the particle fluid emitters in the DOP network. For the sphere emitter I have appended the color attribute to the POP network entitled “PARTICLE_SOURCE_POP”. For the default emitter I have appended the color attribute to the POP network entitled “PARTICLE_STREAM_PREBUILT”.
WHAT WORKS:
I have applied the gas diffuse node to the merge node connecting the two emitters, and have set the gas diffuse node to be the first in the order of operations for the merge node. The blend of colors is working fine.
THE PROBLEM:
My problem is that the sphere emitter is set to stop birthing particles after frame 2, but it keeps emitting particles as though it is referencing the default emitter somehow. I see the initial particles of the sphere emitter stop on frame 2, but then starting of frame 3 they begin to emit using the parameters established in the other emitter.
SOME QUESTIONS THIS ISSUE HAS FORCED ME TO PONDER
1. Is this an issue with order of operations in the merge node somehow?
2. Can you use two emitters of different types in the same simulation?
3. Is there some parameter in which one emitter is referencing the other that I don't know about?
4. Is there some issue with the way that the particle fluid object attached to the particle fluid solver is treating the two separate emitters.
I tried to make this as easy to understand as possible and I am including the Houdini file. Any help on this would be super amazing.
respectfully,
Adam
I have been trying to get this to work for me for a couple days now and I have seriously come to a wall. I've tapped out every resource I have other than this one in order to find the answer. If anyone can take a look at this file and help me out it would be truly amazing and I would be very thankful indeed!
WHAT I HAVE DONE:
I am trying to use a gas diffuse node to blend the colors of the fluid particles being emitted from two separate emitters. The first emitter is a polygon sphere using impulse activation and impulse birth rate. The second emitter is a default emitter using stream activation.
I have appended a color attribute to the POP networks inside of each of the particle fluid emitters in the DOP network. For the sphere emitter I have appended the color attribute to the POP network entitled “PARTICLE_SOURCE_POP”. For the default emitter I have appended the color attribute to the POP network entitled “PARTICLE_STREAM_PREBUILT”.
WHAT WORKS:
I have applied the gas diffuse node to the merge node connecting the two emitters, and have set the gas diffuse node to be the first in the order of operations for the merge node. The blend of colors is working fine.
THE PROBLEM:
My problem is that the sphere emitter is set to stop birthing particles after frame 2, but it keeps emitting particles as though it is referencing the default emitter somehow. I see the initial particles of the sphere emitter stop on frame 2, but then starting of frame 3 they begin to emit using the parameters established in the other emitter.
SOME QUESTIONS THIS ISSUE HAS FORCED ME TO PONDER
1. Is this an issue with order of operations in the merge node somehow?
2. Can you use two emitters of different types in the same simulation?
3. Is there some parameter in which one emitter is referencing the other that I don't know about?
4. Is there some issue with the way that the particle fluid object attached to the particle fluid solver is treating the two separate emitters.
I tried to make this as easy to understand as possible and I am including the Houdini file. Any help on this would be super amazing.
respectfully,
Adam
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