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]
Found 5515 posts.
Search results Show results as topic list.
Technical Discussion » What's stamps()?
- tamte
- 8588 posts
- Offline
Technical Discussion » How to read Geometry Spreadsheet in DOP
- tamte
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
- 8588 posts
- Offline
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
Houdini Indie and Apprentice » Creating geometry in python module of a digital asset?
- tamte
- 8588 posts
- Offline
you need something to hold your created geo, for that you can use Data parm
since you want to output the geo you can use Stash SOP inside and promote it's data parm (stash) to your HDA so that it's editable and you can hide it
then in your HDA Python Module you can have a function that creates and stores geo in this data parm and incoke it through button callback
since you want to output the geo you can use Stash SOP inside and promote it's data parm (stash) to your HDA so that it's editable and you can hide it
then in your HDA Python Module you can have a function that creates and stores geo in this data parm and incoke it through button callback
Technical Discussion » Should Voxel Size match in nodes?
- tamte
- 8588 posts
- Offline
source volume will be sampled at the solver's resolution during sourcing so your source can be the same or lower resolution, (since matching pyro may not always be necessary if such resolution is not needed for the source detail)
I'd avoid higher than solver's resolution
I'd avoid higher than solver's resolution
Edited by tamte - 2024年4月11日 03:35:31
Technical Discussion » Polygon curve to Bezier curve convert issue..!
- tamte
- 8588 posts
- Offline
you can append Convert SOP, set to Bezier Curve and check Interpolate Through Hulls, then if you want you can append another Curve SOP and continue editing as bezier
Edited by tamte - 2024年4月7日 17:17:16
Technical Discussion » If we can program in this editor, does that mean we can solv
- tamte
- 8588 posts
- Offline
Staglaitorno
If we can program in this editor, does that mean we can solve any problem? A cure-all?
Houdini Indie and Apprentice » Animated Solaris camera to OBJ network?
- tamte
- 8588 posts
- Offline
Houdini Indie and Apprentice » Deflate mesh to its original position
- tamte
- 8588 posts
- Offline
you need to be more specific if you want us to understand your exact workflow, there is many ways to even do inflate and how to deflate may depend on the specific way you are using
assuming you are doing your inflation in Vellum Constraint Properties DOP by animating rest length scale of your Pressure constraints
so to deflate decrease the Rest Length Scale of Pressure constraints back to 1
and if you really want the position to align with the original make sure to create Soft Pin constraints beforehand with 0 or very low stiffness and increase it gradually during deflating to force your geo points to return to their initial pos
assuming you are doing your inflation in Vellum Constraint Properties DOP by animating rest length scale of your Pressure constraints
so to deflate decrease the Rest Length Scale of Pressure constraints back to 1
and if you really want the position to align with the original make sure to create Soft Pin constraints beforehand with 0 or very low stiffness and increase it gradually during deflating to force your geo points to return to their initial pos
Technical Discussion » Copy 1st value of vertex array attribute to a point float
- tamte
- 8588 posts
- Offline
this should also work, since even float signature can read vector attribute, in which case it will return only the first component
f@u = vertex(0, "uv", @vtxnum);
-
- Quick Links