Hi,
i´m a student and really new to houdini. For a Project i want to create a effect like a ink drop drops in Water. What Tools should i use to get this effect?
thanks
Ink Drop in Water
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- Ti Mo
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- cgcris
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- Sadjad Rabiee
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1. Create a downward Smoke simulation (i.g set Buoyancy Y to -1) from a simple sphere
2. Create million of the particles from same source (Sphere).
3. Use Advect by Volume POP node in the AutoDopNetwork for applying Smoke velocity to the particles , in this case the particles having exactly same motion like Smoke
4. set very small value for PScale of the particle and turn off Smoke for rendering (just particles should be render)
5. Turn on Motion Blur in the Mantra node
6. Turn on Geometry Velocity Blur for Particles (Particles Geometry node –> Render – > Geometry Velocity Blur)
7. Apply any desire material to the particles , you can use Constant material with black color and very small alpha too.
Now you should take same result :wink:
2. Create million of the particles from same source (Sphere).
3. Use Advect by Volume POP node in the AutoDopNetwork for applying Smoke velocity to the particles , in this case the particles having exactly same motion like Smoke
4. set very small value for PScale of the particle and turn off Smoke for rendering (just particles should be render)
5. Turn on Motion Blur in the Mantra node
6. Turn on Geometry Velocity Blur for Particles (Particles Geometry node –> Render – > Geometry Velocity Blur)
7. Apply any desire material to the particles , you can use Constant material with black color and very small alpha too.
Now you should take same result :wink:
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- Sadjad Rabiee
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- Sadjad Rabiee
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- Enivob
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@Joker: I am trying to follow your steps to re-create the ink drop but I am a little lost. I am attaching my file with some of the steps completed. But other steps I am not sure how to complete.
For instance, where do I set the Pscale value? Where is the Geometry Velocity Blur for particles?
For some reason my particles just immediately fall down and don't follow or cling to the smoke…?
For instance, where do I set the Pscale value? Where is the Geometry Velocity Blur for particles?
For some reason my particles just immediately fall down and don't follow or cling to the smoke…?
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
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- Sadjad Rabiee
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1. You have couple ways for setting PScale :
Solution A :
adding a POP Wrangle node inside AutoDopNetwork and connect it to network (between POP Source node and Merge node)
Then use this expression for setting PScale:
f@pscale = 0.01;
Solution B :
add a Point SOP in the source_particles network and connect import_source node to Point SOP , then in the Point SOP parameters in the Particle tab change Keep Scale parameter to Add Scale , then delete $PSCALE expression and set your desire PScale value , for example 0.01;
2. Where is Velocity Blur !?
select source_particles node in the Object Level , in it's parameters go to Render–>Sampling and turn on Geometry Velocity Blur
then in the Mantra node you have to turn on Motion Blur parameter in the Mantra node–>Rendering
About Advecting particles question you should add POP Advect By Volumes node between POP Source and Merge node , then in the parameters of this node , set Advection Type to Update Velocity and also set Velocity Blend to 1.
I hope you can solve your problems
:idea:
Solution A :
adding a POP Wrangle node inside AutoDopNetwork and connect it to network (between POP Source node and Merge node)
Then use this expression for setting PScale:
f@pscale = 0.01;
Solution B :
add a Point SOP in the source_particles network and connect import_source node to Point SOP , then in the Point SOP parameters in the Particle tab change Keep Scale parameter to Add Scale , then delete $PSCALE expression and set your desire PScale value , for example 0.01;
2. Where is Velocity Blur !?
select source_particles node in the Object Level , in it's parameters go to Render–>Sampling and turn on Geometry Velocity Blur
then in the Mantra node you have to turn on Motion Blur parameter in the Mantra node–>Rendering
About Advecting particles question you should add POP Advect By Volumes node between POP Source and Merge node , then in the parameters of this node , set Advection Type to Update Velocity and also set Velocity Blend to 1.
I hope you can solve your problems
:idea:
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- Sadjad Rabiee
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- Enivob
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Thanks for the info and screenshots.
I went ahead and rebuilt my simulation following your steps, I only use 10,000 particles, not a million, however.
I think I am close but the particles still do not cling to the smoke all that well even with Velocity Blend set at 1.0.
The smoke seems to have some built-in boundary that causes it to collide with an invisible floor at world origin. The particles just pass through that barrier. I reviewed boundaries for the pyro sim and Enforce Boundaries are not enabled so I am not sure why there is a floor collide?
I realize I can move the camera and sphere way up in the y-direction to avoid the ground plane issue. Is that what most people do? Or is there a better solution?
I went ahead and rebuilt my simulation following your steps, I only use 10,000 particles, not a million, however.
I think I am close but the particles still do not cling to the smoke all that well even with Velocity Blend set at 1.0.
The smoke seems to have some built-in boundary that causes it to collide with an invisible floor at world origin. The particles just pass through that barrier. I reviewed boundaries for the pyro sim and Enforce Boundaries are not enabled so I am not sure why there is a floor collide?
I realize I can move the camera and sphere way up in the y-direction to avoid the ground plane issue. Is that what most people do? Or is there a better solution?
Using Houdini Indie 20.0
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
Windows 11 64GB Ryzen 16 core.
nVidia 3050RTX 8BG RAM.
-
- Sadjad Rabiee
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- Enivob
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