use RigPose SOP
- you can either take advantage of control points being in a hierarchy if you animate tail or somethin
- or turn on World Space and animate each point independently
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Houdini Indie and Apprentice » How to manually animate a curve?
- tamte
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Houdini Indie and Apprentice » FEM and Vellum as mutual affectors?
- tamte
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gordig
I found some time to try out Vellum Tet sims, and I'm having three problems with it:
- I can't figure out how to set the strength high enough that the figure holds its shape well enough for my liking
- Because of #1, I also can't scale the stiffness with attributes such that the only parts that deform are the ones I want to deform.
- Regardless of #1 and #2, I can't figure out how to run the animated figure through the simulation. I'm guessing I'll have to simulate the figure in base pose, then drive the simulated figure through a point deform, much like with a FEM sim.
1. your figure seems pretty stiff, probably more than you need so I don;t think it needs to be stiffer
2. you don't need to vary the tet stiffness to get what you are after, what you want is to add Soft Pin Constraint with Match Animation checked and let that define what parts follow the animation of target geometry with full stiffness ( areas aroud "skeleton") and which are completely free, or anything inbetween
so if you use your "targetstrength" parameter for that make is 0-1 mask as stiffness scaling parameters are applied logarithmically
3. Pin To Target Constraint with Match Animation on and control the stiffness like mentioned in 2.
to optimize the setup you can also use Hard Pin constraint for points that you want to fully follow animation (like areas around "bones") instead of having those also be very stiff soft pin constraints, however you may run into some issues and jitter if you force hard constrained points into some impossible situations
Rigging » Joint Biharmonic Capture : Max Number of Joint Influences?
- tamte
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erikmlvyou can still use Capture Correct SOP should work fine on capture attribute from Joint Capture Biharmonic
I found what it seems an old SOP called "CaptureCorrect" but that seems to be tailored to OBJ level bones.
Is there a "contemporary" way of setting max number of influences?
or if you want more control modifying weights overall you can use Capture Attribute Unpack -> Wrangle -> Capture Attribute Pack
Technical Discussion » Creating post surgery organs's Adhesions procedurally?
- tamte
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you can play with Attribute Blur SOP after your Connect Adjacent
- in Group set all points except for anchor points
- uncheck Fix Border Points as for Curves all points are border points
- additionally you can control it by weight attrib
- also play with creating your connections, essentialy you probably want the adjacent connections only between lines of the same clusters or something to not have cross webbing
- in Group set all points except for anchor points
- uncheck Fix Border Points as for Curves all points are border points
- additionally you can control it by weight attrib
- also play with creating your connections, essentialy you probably want the adjacent connections only between lines of the same clusters or something to not have cross webbing
Technical Discussion » How to set aerodynamic drag for Vellum fluid?
- tamte
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raincoletry higher values maybe? It defilinely should apply drag to Vellum Fluid particles
Set POP Drag's air resistance without wind seems to do nothing
on Vellum Solver SOP you can also use Forces/Built In Wind Drag, which is linked to internal POP Wind, but regardless ow what POP Wind or POP Drag you use you should see the effect
Solaris and Karma » Rendering emissive transparent shaders
- tamte
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if you render pure emissive volume it will have no Alpha, which is correct and it will also not block any other light
the comp should be simple, just Add over the plate, not sure how it's called in AE, in Nuke is called Plus
Assuming your soft assumes the image is already premultiplied (which it should) you can also use Over, since if Alpha is 0 then over is the same as Plus: A + B(1-alpha) = A + B(1-0) = A + B
the comp should be simple, just Add over the plate, not sure how it's called in AE, in Nuke is called Plus
Assuming your soft assumes the image is already premultiplied (which it should) you can also use Over, since if Alpha is 0 then over is the same as Plus: A + B(1-alpha) = A + B(1-0) = A + B
Technical Discussion » What's stamps()?
- tamte
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raincoleCorrect, the value you see is the 3rd argument of stamp*() function, which defines a default value shown when evaluated out of context
What confuses me is that I can middle click the parameter to show its value even it uses stamps(), just like other expressions. But if stamps() is evaluated during cook, does it mean the value we see by middle clicking it is not necessarily meaningful?
Doesn't have to be meaningless, it's certainly a placeholder
Edited by tamte - 2024年4月18日 22:40:52
Technical Discussion » What's stamps()?
- tamte
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In SOPs there used to be Copy SOP, lafer renamed to Copy Stamp SOP and deprecated, which allowed you to define "stamping variables" which could vary values per each copy
stamp() function for floats and stamps() for string were a way to evaluate such variables of a specific node per each copy and therefore modify left side nodes for each copy
This was replaced by for loops due to several technical reasons
However stamp() and stamps() were and still are also used in DOPs in a similar fashion, to evaluate certain variable values during cook and therefore being able to change behavior of nodes like SOP Solver based on which object is currently running over etc.
More info here https://www.sidefx.com/docs/houdini/nodes/dop/sopsolver.html [www.sidefx.com]
stamp() function for floats and stamps() for string were a way to evaluate such variables of a specific node per each copy and therefore modify left side nodes for each copy
This was replaced by for loops due to several technical reasons
However stamp() and stamps() were and still are also used in DOPs in a similar fashion, to evaluate certain variable values during cook and therefore being able to change behavior of nodes like SOP Solver based on which object is currently running over etc.
More info here https://www.sidefx.com/docs/houdini/nodes/dop/sopsolver.html [www.sidefx.com]
Edited by tamte - 2024年4月18日 21:10:10
Technical Discussion » How to read Geometry Spreadsheet in DOP
- tamte
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raincoleroughly, FORCE is evaluated Pre-Solve, SOURCE is Post-Solve
I'm still quite confused about when I should connect to FORCE and when to SOURCE tho.
for more specific details you can look inside of the solver if you are interested when exactly each of them evaluates
Technical Discussion » How to read Geometry Spreadsheet in DOP
- tamte
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it's unlikely to be a bug, at least in my experience the spreadsheet is reliable
are you on the first simulation frame by any chance? in Vellum sourcing happens after forces are applied so any freshy sourced constraints will not receive your new restlength on that timestep
so maybe try plugging your node to SOURCE Output node, since that one is evaluated after internal source
are you on the first simulation frame by any chance? in Vellum sourcing happens after forces are applied so any freshy sourced constraints will not receive your new restlength on that timestep
so maybe try plugging your node to SOURCE Output node, since that one is evaluated after internal source
Edited by tamte - 2024年4月18日 19:31:09
Houdini Indie and Apprentice » FEM and Vellum as mutual affectors?
- tamte
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definitely try vellum tetrahedral softbody since Muscle tools are also using those and 19.5 got a few updates that were getting the behavior closer to FEM
you can watch this https://vimeo.com/739693945 [vimeo.com] ideally from beginning, but at ~ 9:20 John compares it to FEM
you can watch this https://vimeo.com/739693945 [vimeo.com] ideally from beginning, but at ~ 9:20 John compares it to FEM
Houdini Indie and Apprentice » FEM and Vellum as mutual affectors?
- tamte
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gordigeach solver must be used only with compatible objects so you can use
So merge the Vellum object and the FEM solid object, then feed that merge into one of the solvers?
Cloth Object + Solid object and FEM Solver
or
Vellum Cloth + Vellum Tetrahedral Softbody and Vellum Solver
I'd personally go with Vellum
Edited by tamte - 2024年4月18日 17:47:52
Technical Discussion » How to read Geometry Spreadsheet in DOP
- tamte
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you are setting for "stretch" group, do the primitives shown in your spreadsheet belong to that group?
DOP spreadsheet will show you data at the end of current timestep so if you are looking at the correct geometry data and modified prims, you should see the updated values
DOP spreadsheet will show you data at the end of current timestep so if you are looking at the correct geometry data and modified prims, you should see the updated values
Technical Discussion » Ray Sop doesn't recognize Cache Data from DOP Import ?
- tamte
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easiest is to post a file, so that you can get exact answer rather than leave us guessing
but here are other possibilities of getting 0 hits or 0 distance, most likely nothing was hit which
- in Project Rays mode can happen if all rays miss, or if the vector is {0,0,0} (so for example if based on Normals, you may have v@N attribute {0,0,0} etc)
- in either mode if you are using Max Distance and all collision geo is further than that
but here are other possibilities of getting 0 hits or 0 distance, most likely nothing was hit which
- in Project Rays mode can happen if all rays miss, or if the vector is {0,0,0} (so for example if based on Normals, you may have v@N attribute {0,0,0} etc)
- in either mode if you are using Max Distance and all collision geo is further than that
Technical Discussion » Ray Sop doesn't recognize Cache Data from DOP Import ?
- tamte
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what is your cached data? Depending on what it is maybe try unpacking it to polygons?
Ray SOP projects points to a surface, there is no reason why it wouldn't work as long as you are feeding it data it expects no matter where that geo came from
Ray SOP projects points to a surface, there is no reason why it wouldn't work as long as you are feeding it data it expects no matter where that geo came from
Solaris and Karma » Can't find Secondary Fire in Karma Pyro Shader!
- tamte
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Atilla explains the new Pyro Shader here https://youtu.be/lXzkxlnQErQ?t=2906 [youtu.be]
starts at 48:26 and at 49:13 he explains the decision why Secondary Fire was removed and what to use instead (49:51)
essentially use the new Karma Fire Emission node to do your secondary, tertiary, etc fire emission
starts at 48:26 and at 49:13 he explains the decision why Secondary Fire was removed and what to use instead (49:51)
essentially use the new Karma Fire Emission node to do your secondary, tertiary, etc fire emission
Animation » Re-simulating a timeline without having to scrub it by hand?
- tamte
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you can Shift+LMB on the brain icon and that will resimulate out of date dopnets in the cook path
Edited by tamte - 2024年4月16日 13:02:26
Houdini Indie and Apprentice » Creating geometry in python module of a digital asset?
- tamte
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has the file that I attached not worked for you?
let me know since it is the fully working example of what you are after and every time you press button it generates diferently positioned point, so fixing your new file would be just repeating myself
the only confusing part in my file may have been that I have hidden the promoted stash parameter as described
promoting is just dragging the stash data parm to the HDA parameters, or adding it there from From Nodes Section
let me know since it is the fully working example of what you are after and every time you press button it generates diferently positioned point, so fixing your new file would be just repeating myself
the only confusing part in my file may have been that I have hidden the promoted stash parameter as described
promoting is just dragging the stash data parm to the HDA parameters, or adding it there from From Nodes Section
Edited by tamte - 2024年4月15日 02:12:23
Solaris and Karma » usd transform affecting pscale/width in render view?
- tamte
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I don't know if HoudiniGL is displaying the actual width, but to me the scaling looks correct
when importing to LOPs:
- your large hair geo has length 1 and pscale about .0075 so width about 0.015
- your small hair geo has length 0.01 but the same width, about 0.015
scaling 100x will not change proportion of length/width so your scaled small hair will render as 1 long (100x0.01) and 1.5 wide (100x0.015)
you can also just zoom in to your small hair before Transform and you will see the proportions are the same
when importing to LOPs:
- your large hair geo has length 1 and pscale about .0075 so width about 0.015
- your small hair geo has length 0.01 but the same width, about 0.015
scaling 100x will not change proportion of length/width so your scaled small hair will render as 1 long (100x0.01) and 1.5 wide (100x0.015)
you can also just zoom in to your small hair before Transform and you will see the proportions are the same
Solaris and Karma » Create AOV from Attribute
- tamte
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assuming you are importing attributes as primvars
then set Source Type on Render Var LOP to Primvar, Source Name to its name (without "primvar:" prefix) and correct Format
just remeber that some attributes are automatically reamed on import like Cd->displayColor, ... so doublecheck what primvars your mesh contains on stage
then set Source Type on Render Var LOP to Primvar, Source Name to its name (without "primvar:" prefix) and correct Format
just remeber that some attributes are automatically reamed on import like Cd->displayColor, ... so doublecheck what primvars your mesh contains on stage
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