I may be missing something obvious here, but this has the same problem as I was describing to Edward - as soon as there's a change in velocity the result goes crazy! New file attached, where the particles slow down at the end. What I want to happen is the cube's roation slow to a stop at the same rate as the particles translation does, but, well, this is not what happens as you will see!
Additionally, this cube animation is just a simplified version of a scene. This needs to be a general solution for any input geometry, hence why I am using time blend through a warp in chops - so I can modify the object's whole animation, not just a single transform.
Cheers
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Houdini Indie and Apprentice » Time-Warping with CHOPS and Copy-Stamping
- Cradders
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Houdini Indie and Apprentice » Time-Warping with CHOPS and Copy-Stamping
- Cradders
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Thanks for the help Joker, but this is not quite what I need. The original particle movement is fine, what I want is for the cubes to rotate at a rate that is proportional to their speed. If the particles move fast, the cubes should rotate quickly. If the particles slow to a stop, the cubes should slow down in their rotation until they're still.
Cheers
Cheers
Houdini Indie and Apprentice » Time-Warping with CHOPS and Copy-Stamping
- Cradders
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Using the geometry CHOP - maybe? I can't figure out how. The stamp expression doesn't seem to transfer over to CHOPs, and I can't directly access the copy node within the chopnet without creating an infinite recursion.
Using the timewarp SOP - at least with the expressions I've been writing, I can vary the ‘amount’ of warping, which is fine for particles moving with no acceleration. But as soon as the object starts to speed up or slow down at any appreciable rate, the time-warped animaton starts jittering about all over the place. The rate is fine, but there's no flow, no connectivity between frames.
If you've got a clever expression in mind, I'm all ears
Using the timewarp SOP - at least with the expressions I've been writing, I can vary the ‘amount’ of warping, which is fine for particles moving with no acceleration. But as soon as the object starts to speed up or slow down at any appreciable rate, the time-warped animaton starts jittering about all over the place. The rate is fine, but there's no flow, no connectivity between frames.
If you've got a clever expression in mind, I'm all ears
Houdini Indie and Apprentice » Edit Point within Group ONLY!
- Cradders
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Working along the lines of what Edward suggested, attached is a scene which does more or less what you want. The only difference is that the group determines what you don't want to be affected, but I'm sure you can build off it.
Here's how it works:
1) Create a group of points that you don't want to be affected by the edit node
2) Do your sculpting through the edit node. This will affect everything.
3) Use an attribcopy to pull the points in the group back to their original position.
Hope this helps!
Here's how it works:
1) Create a group of points that you don't want to be affected by the edit node
2) Do your sculpting through the edit node. This will affect everything.
3) Use an attribcopy to pull the points in the group back to their original position.
Hope this helps!
Houdini Indie and Apprentice » Material Shader Builder - displacement
- Cradders
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This guy is the gear menu. You can find it at the top-right of the node parameters tab.
Houdini Indie and Apprentice » Time-Warping with CHOPS and Copy-Stamping
- Cradders
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Hey,
So I'd like to warp the speed of an animation on an object - the faster an object is moving, the faster the animation plays out. The object will speed up and slow down, it's not just moving at a constant speed. I'm very new to CHOPs but it seems that the warp chop is ideal for this - use a velocity channel (with some maths) as the warp curve and boom. I'd like to do this for hundreds of objects, hence copy-stamping geo onto a particle system.
The question is - how can you get the velocity of a particle piped into the chopnet for the associated copy-stamped object? Is this even possible? When using chops on a single instance of more complicated geo it seems quite slow to cook, so is this even an efficient way of doing things? Before using chops I was initially using a normal timewarp SOP with an expression to vary output range, but this never seemed to work the way I intended.
Attached is a test scene where I've laid out what I've done so far. Any help is as always greatly appreciated!
So I'd like to warp the speed of an animation on an object - the faster an object is moving, the faster the animation plays out. The object will speed up and slow down, it's not just moving at a constant speed. I'm very new to CHOPs but it seems that the warp chop is ideal for this - use a velocity channel (with some maths) as the warp curve and boom. I'd like to do this for hundreds of objects, hence copy-stamping geo onto a particle system.
The question is - how can you get the velocity of a particle piped into the chopnet for the associated copy-stamped object? Is this even possible? When using chops on a single instance of more complicated geo it seems quite slow to cook, so is this even an efficient way of doing things? Before using chops I was initially using a normal timewarp SOP with an expression to vary output range, but this never seemed to work the way I intended.
Attached is a test scene where I've laid out what I've done so far. Any help is as always greatly appreciated!
Houdini Indie and Apprentice » Age of particles in a group
- Cradders
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That is awesome Francisco, thank you very much! That looks like a trick I'll be using for years to come. Really cool. Thanks for your help as well, Tomas.
Houdini Indie and Apprentice » Age of particles in a group
- Cradders
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Yes indeedy - since posting this I've been looking at collision detection POPs and I'm making some progress, but any pointers would be helpful.
Houdini Indie and Apprentice » Age of particles in a group
- Cradders
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Hey, me again.
So general question - I'm grouping particles with a popgroup DOP. I'd like to capture the frame, or the age, or some information relating to when the particular particle becomes part of a group. How could I go about doing this? If I can't do it with groups how else would I acheive this? It's like I need to flag an event per-particle so it can smoothly transition from one state to another.
Cheers
So general question - I'm grouping particles with a popgroup DOP. I'd like to capture the frame, or the age, or some information relating to when the particular particle becomes part of a group. How could I go about doing this? If I can't do it with groups how else would I acheive this? It's like I need to flag an event per-particle so it can smoothly transition from one state to another.
Cheers
Houdini Indie and Apprentice » Re-orienting particle normals
- Cradders
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Wow, even easier than I thought it might be! Both short and long answers much appreciated. Many thanks
Houdini Indie and Apprentice » Re-orienting particle normals
- Cradders
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Hi, another newbie question:
How can I orient points (and thus the geo that is copied onto it) so that they're always pointing ‘up’, while still facing in their direction of movement? Like people walking up a hill - they're facing in the direciton they're walking, but they're always vertical, not perpendicular to the hill's surface.
I've been flailing about trying to rotate normals for a few hours now - I'm sure its some basic maths which is lost on me.
Attached is a scene illustrating my problem (some may recognise it ) - help as always is greatly appreciated!
How can I orient points (and thus the geo that is copied onto it) so that they're always pointing ‘up’, while still facing in their direction of movement? Like people walking up a hill - they're facing in the direciton they're walking, but they're always vertical, not perpendicular to the hill's surface.
I've been flailing about trying to rotate normals for a few hours now - I'm sure its some basic maths which is lost on me.
Attached is a scene illustrating my problem (some may recognise it ) - help as always is greatly appreciated!
Houdini Indie and Apprentice » Keep hard edges on import and export?
- Cradders
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I fully admit I'm a relative newbie to the Houdini giants on this forum, but I'd suggest you look at the Facet SOP. There are check boxes for computing normals, as well as an option to cusp polygons to ‘permanently’ set their hardness.
A copy of your file would be helpful!
A copy of your file would be helpful!
Houdini Indie and Apprentice » Help with Basic Point Instancing
- Cradders
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Houdini Indie and Apprentice » Help with Basic Point Instancing
- Cradders
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Hello,
I'm trying to figure out how to do point instancing, so I can render complex geometry at render time. I'm trying to follow the steps on this page:
http://www.sidefx.com/docs/houdini13.0/copy/instancing [sidefx.com]
As I understand it, you use an intance node at object level, which is basically a normal geo node with a few extra settings. In my mind I need the GEO to instance and the POINTS to instance on to, but I can't see how to link the two. Attached is a scene with this stuff in - I've got a geo node containg some points (cached from a particle sim) and an instance node with a box inside - the geo I want to instance. What am I doing wrong?! Any help would be greatly appreciated!
I'm trying to figure out how to do point instancing, so I can render complex geometry at render time. I'm trying to follow the steps on this page:
http://www.sidefx.com/docs/houdini13.0/copy/instancing [sidefx.com]
As I understand it, you use an intance node at object level, which is basically a normal geo node with a few extra settings. In my mind I need the GEO to instance and the POINTS to instance on to, but I can't see how to link the two. Attached is a scene with this stuff in - I've got a geo node containg some points (cached from a particle sim) and an instance node with a box inside - the geo I want to instance. What am I doing wrong?! Any help would be greatly appreciated!
Houdini Indie and Apprentice » Weird Whitewater Whooshes
- Cradders
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Forgive the alliterative subject, but I've been playing around with flip fluids and I've got an issue with the whitewater solver results that I can't figure out.
I've been working on a large scale scene where a giant whale ship launches out of the ocean (because why not) and as you can see in the attached video and screenshot I get these super-fast, super-straight streams of spray shooting outwards. I think the same thing is happening at a smaller scale right at the beginning of the ship emerging from the water, but I can live with that. What could be causing this? This doesn't happen at higher particle separation.
A second question - as I understand it, to render the ocean, the ocean particles must be converted to a mesh. I'd actually prefer that some of my FLIP ocean looked like spray instead - could I just isolate these particles and render as spray instead of using them in the mesh creation?
Any help would be greatly appreciated! If you need any more information let me know. Cheers!
I've been working on a large scale scene where a giant whale ship launches out of the ocean (because why not) and as you can see in the attached video and screenshot I get these super-fast, super-straight streams of spray shooting outwards. I think the same thing is happening at a smaller scale right at the beginning of the ship emerging from the water, but I can live with that. What could be causing this? This doesn't happen at higher particle separation.
A second question - as I understand it, to render the ocean, the ocean particles must be converted to a mesh. I'd actually prefer that some of my FLIP ocean looked like spray instead - could I just isolate these particles and render as spray instead of using them in the mesh creation?
Any help would be greatly appreciated! If you need any more information let me know. Cheers!
Houdini Indie and Apprentice » Metaball force on particles
- Cradders
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Hey guys,
I'm just trying to get a metaball force to work on a particle sim I've got going. It's a very straightforward sim (attached) but I just can't get the metaball force to seemingly interact with the particles.
What am I missing?
Any help much appreciated!
I'm just trying to get a metaball force to work on a particle sim I've got going. It's a very straightforward sim (attached) but I just can't get the metaball force to seemingly interact with the particles.
What am I missing?
Any help much appreciated!
Houdini Indie and Apprentice » Material only rendering on first frame
- Cradders
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Houdini Indie and Apprentice » Material only rendering on first frame
- Cradders
- 28 posts
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Hi guys,
So I'd imagine this is a silly problem, but I have a rendering problem. I've got a bee - an OBJ imported from Maya. I've assigned a simple material with color map. The material appears fine on frame 1, but disappears on every other frame. The bee just renders pink instead. File attached. I've attached the original OBJs and texture as well.
Any help would be greatly appreciated!
Cheers
Cradders
So I'd imagine this is a silly problem, but I have a rendering problem. I've got a bee - an OBJ imported from Maya. I've assigned a simple material with color map. The material appears fine on frame 1, but disappears on every other frame. The bee just renders pink instead. File attached. I've attached the original OBJs and texture as well.
Any help would be greatly appreciated!
Cheers
Cradders
Houdini Indie and Apprentice » Pyro sim not inheriting velocity from packed primitives?
- Cradders
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Hi guys,
I can't seem to get a pyro sim to inherit the velocity of packed primitives used in an RBD simulation. Any help would be greatly appreciated. Attached are two files - PYROsetup.hip contains a pyro sim which currently does not seem to inherit the velocity of the cached RBD packed primitive sim that was originally setup in RBDsetup.hip
Cheers,
Cradders
I can't seem to get a pyro sim to inherit the velocity of packed primitives used in an RBD simulation. Any help would be greatly appreciated. Attached are two files - PYROsetup.hip contains a pyro sim which currently does not seem to inherit the velocity of the cached RBD packed primitive sim that was originally setup in RBDsetup.hip
Cheers,
Cradders
Houdini Indie and Apprentice » Age for point attribute
- Cradders
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Hi guys,
I have a setup where geometry is deleted depending on its velocity. So primitives come and go depending on how fast they're going. I'd like to create an attribute that defines the age of any particular point in the geometry. Attached is an example file. You'll see in the example that one sphere starts moving half way through the timeline, so their age would need to start at this point. It seems $AGE only works for particles.
Thanks!
I have a setup where geometry is deleted depending on its velocity. So primitives come and go depending on how fast they're going. I'd like to create an attribute that defines the age of any particular point in the geometry. Attached is an example file. You'll see in the example that one sphere starts moving half way through the timeline, so their age would need to start at this point. It seems $AGE only works for particles.
Thanks!
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