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Houdini Lounge » Volume I/O Houdini <=> 3DS Max
- goldleaf
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If it doesn't work with vdbs, the Field3d tools are in the hdk files, and are pretty simple to compile (on Linux, OS X at least).
Houdini Lounge » Questions about Houdini Bullet
- goldleaf
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Thanks for that info cwhite! Didn't realize that about either of those!
I can't seem to get compound shapes using Convex Hull per Connected Primitive. Do you have an example of how this works? I tried it with spheres, but they just behave as individual spheres. I even added a name attribute for each group of primitives, but it seems I'm missing something…
BTW, the doc page for RBD Packed Object is excellent! As are the examples; very informative! My rbd knowledge is definitely out of date!
I can't seem to get compound shapes using Convex Hull per Connected Primitive. Do you have an example of how this works? I tried it with spheres, but they just behave as individual spheres. I even added a name attribute for each group of primitives, but it seems I'm missing something…
BTW, the doc page for RBD Packed Object is excellent! As are the examples; very informative! My rbd knowledge is definitely out of date!
SI Users » Translating ICE Roll Object Scene to Houdini
- goldleaf
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SI Users » Flip Solver Collision Inside Closed Volume
- goldleaf
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Ah, sorry about that. What I did with the transform, and inverting the sign should still help.
Is this more of what you're looking for?
Is this more of what you're looking for?
Houdini Lounge » Questions about Houdini Bullet
- goldleaf
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1) I've never heard of auto-constraints for intersecting objects. Sounds like a different bullet-based solver, as far as I know. derek or cwhite would know for sure I think. The split impulse setting makes resolving intersections move the objects without adding velocity, to avoid explosions. Not that it eliminates them, but its useful (on by default I think).
2) Choosing ‘Set Always’ on the Time node, for some reason, cooks every frame, rather than just the initial frame. Even though the initial value is an expression, I don't think it's updating the Geometry data. But Set Always does. That Set Initial on the SOP Path was an accident, and doesn't do anything since the default is also Set Initial.
I'll file a bug with SESI about the disappearing geometry. Something to do with Packed Prims for sure. Thanks for confirming it!
6) The BakeODE SOP just add attributes for the Bullet and ODE Solvers. It was created when ODE was the only alternate solver to the RBD Solver, for Houdini 10; it was modified to work with Bullet, but has kept the same name. That is confusing though, and I wonder if/when they'll rename it. But yeah, Bullet solver only in the hip file; I did a test a few years ago, when Bullet wasn't part of Houdini, v10, and lots of stacking would cause ODE to explode after a while, while Bullet just kept chugging along. I'd be curious if anyone outside of proprietary studio tools is really using it.
Glad to help!
2) Choosing ‘Set Always’ on the Time node, for some reason, cooks every frame, rather than just the initial frame. Even though the initial value is an expression, I don't think it's updating the Geometry data. But Set Always does. That Set Initial on the SOP Path was an accident, and doesn't do anything since the default is also Set Initial.
I'll file a bug with SESI about the disappearing geometry. Something to do with Packed Prims for sure. Thanks for confirming it!
6) The BakeODE SOP just add attributes for the Bullet and ODE Solvers. It was created when ODE was the only alternate solver to the RBD Solver, for Houdini 10; it was modified to work with Bullet, but has kept the same name. That is confusing though, and I wonder if/when they'll rename it. But yeah, Bullet solver only in the hip file; I did a test a few years ago, when Bullet wasn't part of Houdini, v10, and lots of stacking would cause ODE to explode after a while, while Bullet just kept chugging along. I'd be curious if anyone outside of proprietary studio tools is really using it.
Glad to help!
SI Users » project "Houdini, a great modeler"
- goldleaf
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Werner Ziemerink
Is there a way to set up a hot key for Edge Loop?
I get that it is just a poly split with Quad Strip enabled, but for some reason I can't find it in the hotkeys editor.
You can right-click on the tool in the shelf, go to the hotkeys tab, and set it there. That is strange it doesn't show up when searching in the Edit > Hotkeys… dialog.
SI Users » Flip Solver Collision Inside Closed Volume
- goldleaf
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Hey Paulo,
I'm not sure why you were getting those problems; here are a few optimizations for getting some collisions inside of a transforming box (the hip file has notes for these too, in case I missed anything here).
- Fluids only use volume collisions, and to get the fluid to stay inside of a shape, you need to turn on Invert Sign
- Using Object transforms is MUCH faster. Deforming geometry means it recalculates the collision sdf every frame.
- There is an example for extracting obj-level transforms from your sop-level transforms, though in your case, you could just copy that animation to the OBJ level.
Not sure why you were having those problems, but hope this helps!
I'm not sure why you were getting those problems; here are a few optimizations for getting some collisions inside of a transforming box (the hip file has notes for these too, in case I missed anything here).
- Fluids only use volume collisions, and to get the fluid to stay inside of a shape, you need to turn on Invert Sign
- Using Object transforms is MUCH faster. Deforming geometry means it recalculates the collision sdf every frame.
- There is an example for extracting obj-level transforms from your sop-level transforms, though in your case, you could just copy that animation to the OBJ level.
Not sure why you were having those problems, but hope this helps!
Houdini Lounge » Questions about Houdini Bullet
- goldleaf
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Hey Ben!
1) Not directly, but you might be able to write a Python DOP to do something for this. The penetration threshold is how much to let object penetrate before resolving the collision, that might be helpful for mid-sim penetrations; but probably not for objects which start out intersecting.
2) I put an example in the hip file
3) These two links should help, the first has an example for keyframe rbd: http://www.sidefx.com/docs/houdini13.0/nodes/dop/rbdkeyactive [sidefx.com] http://www.sidefx.com/docs/houdini13.0/dyno/keyframe [sidefx.com].
4) It's possible, but I can't remember/figure out how to count impacts, since the impacts data is just for the current frame.
5) No idea, sorry
6) There is an example in the hip file for emitting objects of different shapes (it uses the RBD Point Object and the Compound collision type, with BakeODE SOPs on the different collision objects).
The hip file also contains a way to get animated packed pieces; however, I've noticed that once cached, the geometry disappears from my viewport. Just a scene view bug, the collisions are still there. You may not encounter it though
And as for setting which objects collide with which, you can see that in the Affector Matrix. Here is a page with info (missing for H13 for some reason? or it's just move/been renamed):http://www.sidefx.com/docs/houdini11.1/dynamics/relationships [sidefx.com]. You can set relationships different ways, though I haven't yet figured out how to disable specific objects from interacting. Maybe with the Apply Relationship DOP, somehow?
Hope that helps!
1) Not directly, but you might be able to write a Python DOP to do something for this. The penetration threshold is how much to let object penetrate before resolving the collision, that might be helpful for mid-sim penetrations; but probably not for objects which start out intersecting.
2) I put an example in the hip file
3) These two links should help, the first has an example for keyframe rbd: http://www.sidefx.com/docs/houdini13.0/nodes/dop/rbdkeyactive [sidefx.com] http://www.sidefx.com/docs/houdini13.0/dyno/keyframe [sidefx.com].
4) It's possible, but I can't remember/figure out how to count impacts, since the impacts data is just for the current frame.
5) No idea, sorry
6) There is an example in the hip file for emitting objects of different shapes (it uses the RBD Point Object and the Compound collision type, with BakeODE SOPs on the different collision objects).
The hip file also contains a way to get animated packed pieces; however, I've noticed that once cached, the geometry disappears from my viewport. Just a scene view bug, the collisions are still there. You may not encounter it though
And as for setting which objects collide with which, you can see that in the Affector Matrix. Here is a page with info (missing for H13 for some reason? or it's just move/been renamed):http://www.sidefx.com/docs/houdini11.1/dynamics/relationships [sidefx.com]. You can set relationships different ways, though I haven't yet figured out how to disable specific objects from interacting. Maybe with the Apply Relationship DOP, somehow?
Hope that helps!
Houdini Lounge » URL for the latest Houdini docs
- goldleaf
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Houdini Lounge » URL for the latest Houdini docs
- goldleaf
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I remember there used to be a URL that always pointed to the latest houdini docs, but for the life of me, I can't find it.
Am I just imagining it existed? Something like sidefx.com/docs/houdini.latest?
Thanks
Am I just imagining it existed? Something like sidefx.com/docs/houdini.latest?
Thanks
Houdini Lounge » exporting Fire and Smoke to another software
- goldleaf
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There are OpenVDB plugins for maya, though you'll need a renderer in maya if that's what you want. Unless there is a tool to convert vdb to maya volumes, but I haven't looked at that.
http://www.openvdb.org/download/ [openvdb.org]
http://www.openvdb.org/download/ [openvdb.org]
Houdini Learning Materials » Accuracy of Bullet Collisions
- goldleaf
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Houdini Learning Materials » Accuracy of Bullet Collisions
- goldleaf
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There is the Bake ODE SOP, lets you combine primitives into a compound collision shape. The name is old, from the days the ODE solver first became part of Houdini, but it works with both ODE and Bullet (not the RBD Solver though).
The documentation has a table for the Bullet Primitive - Houdini geometry conversion.
http://www.sidefx.com/docs/houdini13.0/nodes/sop/bakeode [sidefx.com]
See the attached example.
The documentation has a table for the Bullet Primitive - Houdini geometry conversion.
http://www.sidefx.com/docs/houdini13.0/nodes/sop/bakeode [sidefx.com]
See the attached example.
Houdini Indie and Apprentice » print question
- goldleaf
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If you run houdini in the foreground, you'll see it from the Terminal you ran it from.
Try this: houdini -foreground
Try this: houdini -foreground
SI Users » Greyed out parameters
- goldleaf
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Check to see if you have a Take set, perhaps? If you created a new take by accident, then parameters would be grey'd out.
SI Users » animation improvements in Houdini
- goldleaf
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In the Channel Editor, press ‘Y’. Now you'll get a bbox around the keys for scaling.
Not in the docs as far as I could tell; found out about it when sending in an RFE for such a feature
Not in the docs as far as I could tell; found out about it when sending in an RFE for such a feature
takita
BTW - does anyone miss the “Region Keys” tool in the XSI Animation Editor?
Like to quickly scale a collection of keys on different curves in value/time (with the box manipulator, possibly even with frame snapping on)?
Personally I'd stopped using the dopesheet and tended to use this more often since it also gave me key values (that I could manipulate if necessary using the same tool without reselecting).
-T
Technical Discussion » Finite Element attributes
- goldleaf
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Figured it out: I needed to set the attributes before the tetrahedralize sop (I had them after). And I'd also set them to be point attrs, when they should have been primitive attributes.
Thanks for the help Michiel!
Thanks for the help Michiel!
Technical Discussion » Finite Element attributes
- goldleaf
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Great, thanks for the explanations; that makes much more sense!
Is there something that needs to be toggled in order for per-point, sop-level attributes to be used by the solver? I can set v for all points, but not on just certain ones. And whenever I set attrs like solidstretchstiffness or solidshearstiffness, it doesn't change the behavior of the results (whether I'm setting all or just some).
There isn't some sort of toggle I have to set right? I've tried setting it on points before and after the tetrahedralize sop, but in both cases, I don't see any changes. I must be missing something simple, but I can't figure out what it could be.
In the attached file, I'm setting attributes to 1 all over, and to 0 on parts, since it's a multiplier, as I understand it.
Thanks so much for the help michiel!
Is there something that needs to be toggled in order for per-point, sop-level attributes to be used by the solver? I can set v for all points, but not on just certain ones. And whenever I set attrs like solidstretchstiffness or solidshearstiffness, it doesn't change the behavior of the results (whether I'm setting all or just some).
There isn't some sort of toggle I have to set right? I've tried setting it on points before and after the tetrahedralize sop, but in both cases, I don't see any changes. I must be missing something simple, but I can't figure out what it could be.
In the attached file, I'm setting attributes to 1 all over, and to 0 on parts, since it's a multiplier, as I understand it.
Thanks so much for the help michiel!
Technical Discussion » how to inherite the source velocity when emitting fluid
- goldleaf
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Also, you might have to uncheck Evaluate within Frame Range, depending on which scheme you choose for calculating velocity. Otherwise, no velocity on the first frame.
Technical Discussion » Finite Element attributes
- goldleaf
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I've been playing around with the finite element solver, and I can't figure out a couple of things:
- What do ‘shell’ and ‘solid’ prefixes refer to in the attributes? Is ‘shell’ for all of the tetrahedra exposed to air, and ‘solid’ are the interior ones?
- How do I get different properties in different parts of the object? In my hip file, I'm trying to vary materialuvw across a small block, but it doesn't seem to be picking up the differing values.
Thanks!
- What do ‘shell’ and ‘solid’ prefixes refer to in the attributes? Is ‘shell’ for all of the tetrahedra exposed to air, and ‘solid’ are the interior ones?
- How do I get different properties in different parts of the object? In my hip file, I'm trying to vary materialuvw across a small block, but it doesn't seem to be picking up the differing values.
Thanks!
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