you don't have to learn every node, there is usually more than 1 solution
you can also animate Global Scale on your attribute randomize, from 0 to your current value instead
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Technical Discussion » cant seem to figure out how to animate a attribute randomize
- tamte
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Technical Discussion » MaterialX in Houdini vs everywhere else?
- tamte
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At this point Id assume every implementation has limits, for example last time I checked Karma XPU supported only up to 2 standard surfaces being mixed and did not support building shaders from Bsdf nodes
So its always good to find out the extends of MtlX support in any particular DCC rather than automatically assuming full support
So its always good to find out the extends of MtlX support in any particular DCC rather than automatically assuming full support
Solaris and Karma » Import detail attribute create indices?
- tamte
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should not be detail specific are you not getting it for point, prim, vertex attribute?
every custom attribute should give you separate :indices array, which is populated by indices if you import attribute as indexed primvar otherwise is empty, but it's important it is there in case you are layering nonindexed primvar over indexed one, as then it needs to zero out the indices array
every custom attribute should give you separate :indices array, which is populated by indices if you import attribute as indexed primvar otherwise is empty, but it's important it is there in case you are layering nonindexed primvar over indexed one, as then it needs to zero out the indices array
Edited by tamte - May 8, 2024 03:45:56
Technical Discussion » Question : for each primitive in vex
- tamte
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if your primitives are all separate you can do this in Point Wrangle
if any of the points is shared among multiple primitives it will get the vertex index value from first connected primitive
i@get = vertexprimindex(0, @vtxnum);
if any of the points is shared among multiple primitives it will get the vertex index value from first connected primitive
Edited by tamte - May 5, 2024 20:21:26
Houdini Indie and Apprentice » RFC
- tamte
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it's unclear what you are asking and especially with just posting a screenshot without any description what you are trying to do
however seeing just the screenshot it looks like you can achieve it with a Ray SOP instead of doing any sims
not really clear what you are doing in the popnet and why you are using vellum grains instead of hair or springs, so you may need to explain more if you want relevant answer
however seeing just the screenshot it looks like you can achieve it with a Ray SOP instead of doing any sims
not really clear what you are doing in the popnet and why you are using vellum grains instead of hair or springs, so you may need to explain more if you want relevant answer
Technical Discussion » Deleting faces of typography
- tamte
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Technical Discussion » cant seem to figure out how to animate a attribute randomize
- tamte
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use Blendshape SOP or Sequence Blend SOP
connect original scatter points to first and randomized to second input, then animate the blend slider
connect original scatter points to first and randomized to second input, then animate the blend slider
Houdini Indie and Apprentice » Writing channel values?
- tamte
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Yes, wrangle is only VEX, you can't use chopcf() as that's a HScript function, VEX closest equivalent is chop() or mentioned chinput() if sampling direct inputs
Those however take sample index not frame so you need to convert that if you want to use frames
Those however take sample index not frame so you need to convert that if you want to use frames
Houdini Indie and Apprentice » Writing channel values?
- tamte
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gordigit will process all samples of the input channels, that's how chops work
This is only when the Wrangle is set to Channels and Samples, or Samples and Channels. If I set it to Channels, it outputs a single 0, and if Samples, a 0 for every frame. Is the current output of the value at every frame workable, or is there a way to output only the value at the current frame?
if you want it to process just current time slice you ether feed it channels that are generated only for current time sample or if the channels are generated for certain time range like from Phoneme CHOP you can insert Trim CHOP inbetween, set to Current Time Slice
or you can also connect phoneme to second input of Channel Wrangle, keep first empty, set channel range to Use Current Frame and sample the phoneme value from 2nd input
float phoneme_value = chinput(1, "phoneme", I); // process phoneme value V = phoneme_value;
however I'd keep it processing all samples rather than introducing time dependency by slicing the channel
Edited by tamte - May 2, 2024 16:20:56
Houdini Indie and Apprentice » Writing channel values?
- tamte
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gordig
... I'm feeding a Phoneme CHOP , outputting the channel Phoneme, into a Channel Wrangle with the following code:
float ph = ch("Phoneme");
printf("%g", ph);
No matter what the value of Phoneme is at the time, the printf always outputs 0. I've tried changing multiple parameters on both CHOPs involved, tried changing the iteration on the Wrangle, even tried things like chattr, chop and chp, but nothing is doing the trick. What am I missing?
channel in Houdini refers to many things and it can get confusing, ch() is to sample channels of parameters, not CHOP channels
but since you are interested in a chop channel coming from input chop ( assuming you named your channel "phoneme" )you can use chinput():
float phoneme_value = chinput(0, "phoneme", I); // to read at the current sample or use custom sample number instead of I
float current_channel_value = V; // read current channel's value at current sample V = 5; //set current channel's value at current sample to 5
Edited by tamte - May 2, 2024 10:43:31
Technical Discussion » Quad Remesh Direction Field
- tamte
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Houdini Indie and Apprentice » Best practices for tweaking simulations?
- tamte
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Since solvers in Houdini are not 100% physical its difficult to rely on specific values unfortunately, even for solvers like Bullet
It definitely helps to understand what each solver is doing, whether it compensates for scale or mass or completely ignores those properties etc ..
Also with vellum things like substeps and iterations play role when tweaking stiffness for example since higher stiffness may need more iterations to converge and effective stiffness also scales with mass, etc ..
Then, after you understand what each solver does, I'd say it's mostly about building intuition about each solver's behavior, the more you use it the more you will understand how it behaves and be able to tweak the right settings quickly
It definitely helps to understand what each solver is doing, whether it compensates for scale or mass or completely ignores those properties etc ..
Also with vellum things like substeps and iterations play role when tweaking stiffness for example since higher stiffness may need more iterations to converge and effective stiffness also scales with mass, etc ..
Then, after you understand what each solver does, I'd say it's mostly about building intuition about each solver's behavior, the more you use it the more you will understand how it behaves and be able to tweak the right settings quickly
Edited by tamte - May 1, 2024 18:16:09
Houdini Indie and Apprentice » Animation Editor: force handles to stay the same length?
- tamte
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you can enable Keep Acceleration Ratio {R} button to adjust both handle lengths at the same time
to force them to be the same length first, you can maybe select them both and set the same accel value
to force them to be the same length first, you can maybe select them both and set the same accel value
Technical Discussion » RBD Material Combine
- tamte
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for them to mutually interact you need to feed both of them to the same RBD Solver node
you can objectmerge your Bricks and Plaster into the same object and plug into RBD Solver
if each of them has constraints you may want to use RBD Pack first, then merge them, then RBD Unpack, optionally define constraints between them, and plug into solver
then to further configure each of them either use RBD Configure on each before RBD Pack or use RBD Configure on merged geo after unpacking using groups to distinguish between them
you can objectmerge your Bricks and Plaster into the same object and plug into RBD Solver
if each of them has constraints you may want to use RBD Pack first, then merge them, then RBD Unpack, optionally define constraints between them, and plug into solver
then to further configure each of them either use RBD Configure on each before RBD Pack or use RBD Configure on merged geo after unpacking using groups to distinguish between them
Solaris and Karma » Treat as light source in Karma XPU
- tamte
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According to docs [www.sidefx.com] not yet for volumes or curves
For now you may need to render it as emissive volume with diffuse or volume limit at least 1 for each object you want to get illuminated or as global settings
For now you may need to render it as emissive volume with diffuse or volume limit at least 1 for each object you want to get illuminated or as global settings
Houdini Indie and Apprentice » How to preview animation while inside vellum solver
- tamte
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While technically it should work, since inside of Vellum Solver SOP is still a DOPnet, I also experienced these solvers to stop updating
I usually end up pinning the viewport while outside before diving in
I usually end up pinning the viewport while outside before diving in
Houdini Indie and Apprentice » How to manually animate a curve?
- tamte
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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
- 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
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
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