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Technical Discussion » How to expand VDB volume A’s bounding box to match volume B,
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- tamte
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Technical Discussion » logic based edge split + group prim number shifting ?
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- tamte
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you may want to attach a hip file with your test geo to see it in broken state, since testing on grid it seems to work fine and groups seem correct apart from it messing up the incoming "corner_to_be" which the code doesn't attempt to correct
also it seems to be written for Detail wrangle but processes each prim independently so you can simplify it for prim wrangle and remove your prim loop as well as split_prims checks as each prim is processed just once regardless
also it seems to be written for Detail wrangle but processes each prim independently so you can simplify it for prim wrangle and remove your prim loop as well as split_prims checks as each prim is processed just once regardless
Houdini Indie and Apprentice » Hotkey 'Select interactively in the viewport' GroupParamter?
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- tamte
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not necessarily for a specific button, but there is a shortcut to do the same thing in the viewport if you press ` (left of 1)
it's in the Select menu called Reselect For Current Tool
it's in the Select menu called Reselect For Current Tool
Technical Discussion » Import dict attributes from SOPs to LOPs
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- tamte
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elovikovI don't think there is on LOP side since usd primvars don't have equivalent type of dict attribs and even when expanding to primvar per key there would probably be ambiguities in terms of nested dicts or name collisions with existing attribs etc.
- Is there a builtin way to do that? Just map to primvars would work great
however in SOPs you can add Attribute Adjust Dictionary set name to your dict attrib and enable Export Attributes: *
that will extract the keys as attributes
you can make a wrapper around SOP Import for this or set it up inside of SOP Create where you bring your data as Object Merge and then extract dict attribs
Edited by tamte - June 13, 2025 09:49:47
Technical Discussion » make active does not working for partial assignment
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- tamte
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can't check out the file, but generally if any of the pieces within glue constrained structure is not active, then te whole glued structure is not active as it's held by that piece
Solaris and Karma » Subframe interpolation issue
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- tamte
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I'm not very caught up on the current capabilities of USD, but I recall in the past that it didn't interpolate transforms correctly and just did some per component lerp for matrices which is useless in many cases
for that reason there is a workaround built into Motion Blur LOP, called Interpolate Fast Transforms, which will build transform timesamples interpolated like transforms using slerp() for rotations
If you are worried about data you can do it just for the Xform prims of your balls
for that reason there is a workaround built into Motion Blur LOP, called Interpolate Fast Transforms, which will build transform timesamples interpolated like transforms using slerp() for rotations
If you are worried about data you can do it just for the Xform prims of your balls
Edited by tamte - June 10, 2025 11:04:05
Technical Discussion » Modify strength (constraint) attribute
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- tamte
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your RBDs went to sleep after the default of 2s of not moving
so either increase the Sleeping Time or set it to 0
so either increase the Sleeping Time or set it to 0
Houdini Indie and Apprentice » Need help with curve normals and extruding
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- tamte
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point normals after extrusion point in the correct direction based on the polygon winding
and forcing them to point in opposite direction without fixing the polygon winding would cause all sorts of issues down the line
so safest is to flip polygons after the fact
- Group Create SOP: use Keep By Normals to group only polygons facing downwards
- Reverse SOP: to reverse that group's polys therefore to fix their geometric normal
- optionally Normal SOP if you already had Point or Vertex normals on the geo that also need to be flipped use the same group to reverse or recompute them
and forcing them to point in opposite direction without fixing the polygon winding would cause all sorts of issues down the line
so safest is to flip polygons after the fact
- Group Create SOP: use Keep By Normals to group only polygons facing downwards
- Reverse SOP: to reverse that group's polys therefore to fix their geometric normal
- optionally Normal SOP if you already had Point or Vertex normals on the geo that also need to be flipped use the same group to reverse or recompute them
Technical Discussion » Update velocity on every frame for RBD solver?
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- tamte
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litoteThen you can either define v@force in SOPs and let the solver inherit that, which will also nicely combines with other forces inside
That overrides the velocity in the RBD Bullet Solver, I want to add to it.
Or if your force depends on the sim data then you can dive inside the solver and do it in a POP Wrangle or POP Force
Houdini Indie and Apprentice » point wrangle node problem(of procedural oil painting tut)
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- tamte
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the differences can be caused by many factors, filtering, color space, sampling positions etc
if you are looking for more specific answers post a hipfile instead of screenshots
if you are looking for more specific answers post a hipfile instead of screenshots
Technical Discussion » Is it possible to dump the original mesh from Sculpt SOP?
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- tamte
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raincolethis would be just guessing, but to me it looks like something developed directly for purposes of the Sculpt SOP's needs
As a side note, what's a "clustered mesh"? There is an (undocumented?) Cluster Mesh SOP inside Sculpt and I'm utterly confused by what it does. Is it related to Cluster SOP?
it seems to be clustering the mesh into chunks and storing as packed prims with some attribs
likely for the performance reasons so that when you paint it doesnt need to modify the whole mesh, just affected clusters
you can potentially use it for tools with similar needs, but as you see managing clusters can get involved and maybe it still needs some supporting tools to make it easier and hence I'm not surprised the node is hidden
Houdini Indie and Apprentice » corrugated metal sheet in vellum
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- tamte
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I'd first try just a simple cloth preset with high bend stiffness before adding other constraint types into the mix, your bend stiffness is extremely low
however Vellum requires enough constraint iterations and or substeps to resolve stiff constraints so you will for sure need to increase those to see the effect
also reducing resolution of your geo in the direction it doesnt need to bend as much will help
here is a simplified scene
however Vellum requires enough constraint iterations and or substeps to resolve stiff constraints so you will for sure need to increase those to see the effect
also reducing resolution of your geo in the direction it doesnt need to bend as much will help
here is a simplified scene
Edited by tamte - June 6, 2025 00:46:52
Technical Discussion » Is it possible to dump the original mesh from Sculpt SOP?
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- tamte
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ah, you want to extract the original shape, I thought you want to dump the stash so that it updates from input
the Sculpt doesn't store the original mesh in original state, it stores clustered mesh with some attribtues that allow you to restore the original shape, however not all attributes mostly just P
the Sculpt itself doesn't seem to preserve the point order even when you use the Erase method if the input topo changed, so it wouldn't just blendhape with other sculpts, but that's probably just a bug
but regardless here is a node that assembles back the un-clustered mesh and restores the original position and point order so you should get back the original shape, most of the insides are stolen from Sculpt itself with small mods
it has to be connected directly after Sculpt SOP
the Sculpt doesn't store the original mesh in original state, it stores clustered mesh with some attribtues that allow you to restore the original shape, however not all attributes mostly just P
the Sculpt itself doesn't seem to preserve the point order even when you use the Erase method if the input topo changed, so it wouldn't just blendhape with other sculpts, but that's probably just a bug
but regardless here is a node that assembles back the un-clustered mesh and restores the original position and point order so you should get back the original shape, most of the insides are stolen from Sculpt itself with small mods
it has to be connected directly after Sculpt SOP
Edited by tamte - June 6, 2025 00:31:49
Technical Discussion » Is it possible to dump the original mesh from Sculpt SOP?
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- tamte
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Technical Discussion » How to deal with non-manifold prims created by Mirror SOP?
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- tamte
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Houdini Indie and Apprentice » point wrangle node problem(of procedural oil painting tut)
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- tamte
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it's difficult to see from screenshot, but it's very likely that your outline curves are closed polygons
and therefore xyzdist() will return 0 everywhere as it will measure distance to that surface and not just to it's outline curve
try inserting Ends SOP before your outline1 node
- set Close U to Unroll With Shared Points
and therefore xyzdist() will return 0 everywhere as it will measure distance to that surface and not just to it's outline curve
try inserting Ends SOP before your outline1 node
- set Close U to Unroll With Shared Points
Edited by tamte - June 5, 2025 10:53:16
Houdini Learning Materials » Instances doesn't get expected color
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- tamte
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you may need to be more specific since in the viewport you should see the color on top of packed prim multiplied with the color inside
Houdini Indie and Apprentice » @nage attribute not in geometry spreadsheet.
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- tamte
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jaminationit doesn't, the @life is set during emission and it's the particle's lifespan
If you have a particle die on impact does Houdini only know the life of the particle after caching?
thanks
if the particle gets killed earlier for whatever reason, the @life is not updated and therefore @nage will still be normalized age across the original lifespan
if you want to update @life to that @nage is normalized age until the particle gets killed you will have to do it yourself post sim
Technical Discussion » modifying constraint
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- tamte
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metaclay2your setup seems working and @strength is 0 for those constraints
It should break on the right part but it's not working . What is wrong ?
however, even 0 strength Glue constraints need impact to break, since Glue objects are treated as a compound RBD with singular COM therefore there is no strain between pieces of the same glued RBD
if you want them to break immediately you can assign them to broken group
@group_broken = 1;
Technical Discussion » hair jittering
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- tamte
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Right, it's also important to make sure your geometry is moving smoothly between frames
So you may need to use TimeBlend SOP to interpolate your geo between frames
You can doublecheck that by turning on fractional frames on timeline and see if your geo moves between frames
So you may need to use TimeBlend SOP to interpolate your geo between frames
You can doublecheck that by turning on fractional frames on timeline and see if your geo moves between frames
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