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Technical Discussion » Connecting adjacent points but of a different group
- aweaklingchild
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You can do this with two sets of vellum glue constraints. "Intra cluster" constraints to hold the grains within the clusters together and "inter cluster" constraints hold the different clusters together near their borders. The trick is to use the cluster attribute in the "Cluster Attrib" parameter on the intra node and in the "Piece Attrib" parameter on the inter node.
Solaris and Karma » Unable to get Camera motion blur in LOPS/karma
- aweaklingchild
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Solaris and Karma » Light Linker Rules
- aweaklingchild
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Setting the exclusion rule on the bark light, in addition to whatever other rules you've already set, stops it from shining light on the box object on my machine. If you're getting a different result, perhaps it's a bug. To stop casting shadows, you have to create a separate shadow rule.
Solaris and Karma » Light Linker Rules
- aweaklingchild
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Try setting the rules on the light itself. Adding the box to the bark light's exclusion list should do what you want.
Solaris and Karma » Ghosting Solaris scene from inside SOP Modify / Instancer
- aweaklingchild
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For some reason if you're in the default /stage it doesn't work. But if you create a lopnet on the /obj level it'll work.
Houdini Indie and Apprentice » Shatter piece names
- aweaklingchild
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This should do the trick: http://www.sidefx.com/docs/houdini12.5/basics/attributevisualization [sidefx.com]
Houdini Indie and Apprentice » Creating flag
- aweaklingchild
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Try adding some animation to the noise in your wind force. Something like $FF * .5 in offset-y. Also play around with low frequency values to get a nice wavy motion.
Technical Discussion » Particles and a perfect follow of curve
- aweaklingchild
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If you want your particles to stick to the path you should be modifying P instead of v, since v is added to P at the end of each step.
Here's one way of doing it with VOPs and a Solver SOP where the rate of travel is scaled against an arbitrary attribute (Cd). Note that there is interpolation happening, so cranking up the speed will result in deviations from the path. If it's a problem, just kill the interpolation and crank up the point count on the path.
Here's one way of doing it with VOPs and a Solver SOP where the rate of travel is scaled against an arbitrary attribute (Cd). Note that there is interpolation happening, so cranking up the speed will result in deviations from the path. If it's a problem, just kill the interpolation and crank up the point count on the path.
Technical Discussion » fitting arbitrary shapes in a box
- aweaklingchild
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Some interesting stuff here: http://forums.odforce.net/index.php?/topic/15903-filling-grid-with-circle-shapes/ [forums.odforce.net]
Technical Discussion » Bullet: Simulation explodes at frame 1 - convex hull problem
- aweaklingchild
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Circusmonkey has it. Use a foreach SOP to run over all your pieces and polyreduce them, then upres after simming with a Copy SOP.
One trick I've discovered is to actually create your convex hulls before handing things off to Bullet. Do this after polyreducing in the foreach. I've been using this technique on high-res, concave-heavy meshes with very good results/stability.
Also check out the original Bullet documentation if you haven't already..lots of helpful info on how collision padding, split impulse, etc.
One trick I've discovered is to actually create your convex hulls before handing things off to Bullet. Do this after polyreducing in the foreach. I've been using this technique on high-res, concave-heavy meshes with very good results/stability.
Also check out the original Bullet documentation if you haven't already..lots of helpful info on how collision padding, split impulse, etc.
Houdini Indie and Apprentice » roughing up?
- aweaklingchild
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Something like this is best done during shading. Use can use your Copy SOP to stamp each brick with a unique ID. In a material you can then use that ID to drive per-brick displacement/bump with some anti-aliased noise. You won't see this in the viewport but it keeps things lightweight.
Though, if you'd rather do it at the geometry level, you can use the same stamping techniques with a Mountain SOP or a VOP SOP that changes P. You'll need to have lots of points to move around though, so you'll want to up the divisions on your original geometry and/or subdivide. This will get heavy pretty quickly, so I suggest going the shading route.
Though, if you'd rather do it at the geometry level, you can use the same stamping techniques with a Mountain SOP or a VOP SOP that changes P. You'll need to have lots of points to move around though, so you'll want to up the divisions on your original geometry and/or subdivide. This will get heavy pretty quickly, so I suggest going the shading route.
Technical Discussion » Hi advance, have any body know about particle interpolation?
- aweaklingchild
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SYmek drops some knowledge on the subject here: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=27302 [sidefx.com]
Technical Discussion » how to get velocity field of particles in dops
- aweaklingchild
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No problem. By upping the resolution of the low-res field (Vector Field with data name “vel” attached to the POP object), I mean decreasing its division size. Since we're trying to transfer points (which don't take up space) to a field (a 3D grid of voxels), how close we can get to estimating the actual position of a point depends on the density/resolution of voxels in the field/volume.
Of course, if the point is to have an efficient workflow, it defeats the purpose if you have to work with super dense or very large fields. It totally depends on your scene, but if you're working with complex, overlapping motion or particles covering a lot of space you might try grouping similar particles and making separate fields for each group that you can then combine later on. Like always, it just depends on your scene and what you can get away with.
Of course, if the point is to have an efficient workflow, it defeats the purpose if you have to work with super dense or very large fields. It totally depends on your scene, but if you're working with complex, overlapping motion or particles covering a lot of space you might try grouping similar particles and making separate fields for each group that you can then combine later on. Like always, it just depends on your scene and what you can get away with.
Technical Discussion » how to get velocity field of particles in dops
- aweaklingchild
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As that post mentions, there are a lot of different ways that you can do this.
If you just have point data that you want to transfer you need to create a velocity volume from your particle's v attribute. This can be done at the SOP or DOP level a ton of different ways. The Volume Velocity SOP is probably the easiest way in SOPs. In DOPs you'll want to use a Gas Field to Particle DOP.
It makes a lot of sense to create the your vel field in your low-res DOP. This also makes it easy if you have other fields in your sim affecting velocity and you want to combine into your vel field with a Linear Combination DOP.
You can bring your vel field into another sim at either the POP or DOP level. The easiest way to do this in POPs is with a Advect by Volume POP but it's super slow. You could probably do it with a VOP POP and get better performance but this is more complicated. Really though, you should do this in DOPs. Attach a SOP Vector field to your POP Object and point it to either a DOP Import Field SOP (if you want to run both sims live) or to a file SOP (if you've cached out your velocity volume).
Here's a file with a couple simple setups. If you template the low-res sim and run one of the examples you'll see there are major discrepancies between the sims. Upping the resolution of the velocity volume will fix some of this but play with extrapolation distance and the different microsolvers too.
If you just have point data that you want to transfer you need to create a velocity volume from your particle's v attribute. This can be done at the SOP or DOP level a ton of different ways. The Volume Velocity SOP is probably the easiest way in SOPs. In DOPs you'll want to use a Gas Field to Particle DOP.
It makes a lot of sense to create the your vel field in your low-res DOP. This also makes it easy if you have other fields in your sim affecting velocity and you want to combine into your vel field with a Linear Combination DOP.
You can bring your vel field into another sim at either the POP or DOP level. The easiest way to do this in POPs is with a Advect by Volume POP but it's super slow. You could probably do it with a VOP POP and get better performance but this is more complicated. Really though, you should do this in DOPs. Attach a SOP Vector field to your POP Object and point it to either a DOP Import Field SOP (if you want to run both sims live) or to a file SOP (if you've cached out your velocity volume).
Here's a file with a couple simple setups. If you template the low-res sim and run one of the examples you'll see there are major discrepancies between the sims. Upping the resolution of the velocity volume will fix some of this but play with extrapolation distance and the different microsolvers too.
Technical Discussion » how to get velocity field of particles in dops
- aweaklingchild
- 23 posts
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Have a look at this thread: http://forums.odforce.net/index.php?/topic/16136-h12-1-flip-sim-changes-with-resolution/ [forums.odforce.net]
Technical Discussion » Sand explosion
- aweaklingchild
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Houdini Indie and Apprentice » Metaball Topology, Quads.
- aweaklingchild
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Houdini Indie and Apprentice » Wood simulation
- aweaklingchild
- 23 posts
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Coming from and going back to Maya with 2D textures is going to be a major hassle. You'll save a lot of time and your sanity if you use a procedural shader in Houdini for your wood, attach it using rest data (instead of UVs) and render with Mantra. Do a search for user lukeiamyourfather. He has some posts out there on the subject.
As for the rest of your DOPs related questions.. you'll get a lot more help from the forums if you post an example file.
As for the rest of your DOPs related questions.. you'll get a lot more help from the forums if you post an example file.
Technical Discussion » voronoi fracture twice
- aweaklingchild
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The “make breakable” shelf tool will setup dynamic fracturing/refracturing in DOPs. If I remember correctly it just lays down a Voronoi Fracture Configure Object dop.
Houdini Indie and Apprentice » Glue Constraint networks and outside rbd interaction
- aweaklingchild
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Take a look inside the sop solver in this example. The glue net is being held in place until its points/bonds start getting deleted out.
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