Hi,
I am building a Boids [www.red3d.com] system in a POPnet using POP wranges. I am trying to work out what's the correct way to apply forces and get the same results in different Time Scales, by setting the parameter on the POPnet.
In the simpler example attached, I have a few points with a popDrag and using a popWrange I set an upwards force just for one frame. If the particles cover 1 unit in 240 frame, I'd expect them to get there in 120 if I set the ScaleTime param on the POPnet, but they go twice as far.
I noticed the f@TimeInc attribute accessible on the POPwrange changes when I adjust the ScaleTime, so I played with the parameters. I got it somewhat close by turning off 'Use Timestep' on the POPWrange and setting the TimeScale param with this expression:
1/ch("../timescale").
It's not really there, so I wonder if it could get more accurate, or a better way to go about it.
Is there maybe an particle attribute that can be
Thank you
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Technical Discussion » POP Wrangle Timestep
- ch3
- 8 posts
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Technical Discussion » viewport keeps changing the camera
- ch3
- 8 posts
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McNistor
Do you have lock camera toggle off? Although just going in and out of SOPs shouldn't deselect your cam even if the lock toggle is off.
I don't have this problem on my end.Image Not Found
Locking the camera prevents this from happening, but that's not a good solution as I may accidentally change the render camera position. I noticed when setting the triple option above the camera selection to view the rest of the scene, also prevents this issue.
I am in houdini Indie 17.0.459
Which version are using?
I will report it as a bug
thanks
Technical Discussion » viewport keeps changing the camera
- ch3
- 8 posts
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I don't think that was always the case, but since a recent update every time I go between SOP levels the active viewport changes to a “No cam”, rather than maintaining the previously selected render camera.
Is there a new setting to prevent this from happening? I find my self re-selecting the render camera in the viewport all the time as I navigate my network.
Is there a new setting to prevent this from happening? I find my self re-selecting the render camera in the viewport all the time as I navigate my network.
Technical Discussion » Vellum for wire simulation
- ch3
- 8 posts
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Hey Tomas,
thanks for sending over an example file. It definitely improves the stiffness, but if I turn the spring side ways it still bends under its own weight. I would need to crank the substeps to 20 and constraint iterations to 500 to get near what I am after, but that seems a bit excessive and slow for just over 100 points of geo.
Maybe the wire solver is faster for what I want.
thanks you and happy holidays
thanks for sending over an example file. It definitely improves the stiffness, but if I turn the spring side ways it still bends under its own weight. I would need to crank the substeps to 20 and constraint iterations to 500 to get near what I am after, but that seems a bit excessive and slow for just over 100 points of geo.
Maybe the wire solver is faster for what I want.
thanks you and happy holidays
Technical Discussion » Vellum for wire simulation
- ch3
- 8 posts
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Can vellum simulate simple wires similar to the wireSolver ?
I am trying to make a polygon line or curve stiff enough so it maintains its shape against any forces, but I am not having much luck making the bend constraint strong enough. Am I missing something or is it not possible at all?
thank you
I am trying to make a polygon line or curve stiff enough so it maintains its shape against any forces, but I am not having much luck making the bend constraint strong enough. Am I missing something or is it not possible at all?
thank you
Technical Discussion » Ground collision problem with wire solver
- ch3
- 8 posts
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If you put together the simplest wiresolver scene with just a line falling and colliding with a ground, there doesn't seem to be any friction what so ever. Changing the physical properties on either the wire object or the ground doesn't seem to make any difference. I tried with both a ‘groundPlane’ node and also with a staticObject referencing a flat and also an uneven surface. The wire just keeps sliding around.
A not so ideal solution is to add a geometry solver and scale down the velocity if @P.y is bellow a height, but that only works for flat surfaces. If I have to go down that road, is there a way to get hit attributes on the wire object, so I can implement something similar with any arbitrary object?
thanks
A not so ideal solution is to add a geometry solver and scale down the velocity if @P.y is bellow a height, but that only works for flat surfaces. If I have to go down that road, is there a way to get hit attributes on the wire object, so I can implement something similar with any arbitrary object?
thanks
Technical Discussion » Large scale destruction with solids and finite element solve
- ch3
- 8 posts
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Hi,
has anyone here in the forums used solids and the finite element solver to do large scale, production level destruction?
I am doing some tests to determine whether we will be using it in a series of shots, but so far my simulations have been rather slow and unstable.
My current test is a moving sphere moving through a section of a wall that has 4-5 different layers to describe the different materials (plaster, wooden beams, cement). I understand that sandwiching multiple objects together and forcing another object through is a very demanding task for the solver, so I am wondering it it is possible to simulate something like that within reasonable turn around times?
All the objects together have around 100k tets in total, I've set it to 25 substeps and 10 collision passes, in an attempt to make the simulation stable. Some frames took more than 45 minutes and even at these calculation times the simulation became unstable and ended up exploding a few frames after the impact.
Is there anything obvious I am missing out in terms of simulation efficiency/stability, or is it just a matter of keep increasing the substeps?
I am attaching my test file, in case you would like to take a look.
Everything is under the ‘diner’ geo node and all yellow nodes are what goes into the purple DOP network.
It takes about a minute to generate all the tet meshes. I could optimize it to just the small section I am simulating, but that's irrelevant to the performance of the simulation itself.
let me know if you have any ideas.
thanks a lot
Georgios
has anyone here in the forums used solids and the finite element solver to do large scale, production level destruction?
I am doing some tests to determine whether we will be using it in a series of shots, but so far my simulations have been rather slow and unstable.
My current test is a moving sphere moving through a section of a wall that has 4-5 different layers to describe the different materials (plaster, wooden beams, cement). I understand that sandwiching multiple objects together and forcing another object through is a very demanding task for the solver, so I am wondering it it is possible to simulate something like that within reasonable turn around times?
All the objects together have around 100k tets in total, I've set it to 25 substeps and 10 collision passes, in an attempt to make the simulation stable. Some frames took more than 45 minutes and even at these calculation times the simulation became unstable and ended up exploding a few frames after the impact.
Is there anything obvious I am missing out in terms of simulation efficiency/stability, or is it just a matter of keep increasing the substeps?
I am attaching my test file, in case you would like to take a look.
Everything is under the ‘diner’ geo node and all yellow nodes are what goes into the purple DOP network.
It takes about a minute to generate all the tet meshes. I could optimize it to just the small section I am simulating, but that's irrelevant to the performance of the simulation itself.
let me know if you have any ideas.
thanks a lot
Georgios
Technical Discussion » lSystems and wireSolver
- ch3
- 8 posts
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How can I simulate an lSystem using the wireSolver?
It's straight forward to set up just the wire, but what if I've spawned geometry on the lSystem using the JKM inputs/functions? Ideally the geometry should just follow the wire in a rigid way, without going through the solver node.
thank you
It's straight forward to set up just the wire, but what if I've spawned geometry on the lSystem using the JKM inputs/functions? Ideally the geometry should just follow the wire in a rigid way, without going through the solver node.
thank you
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