Hello all.
I've been going down the list of built-in handles in Houdini, trying to understand how they all work, connect to parameters, etc. However I'm finding they're not incredibly well documented, and am constantly running into walls trying to use them and not finding answers in the documentation. And so humbly turn to you, the Houdini community, to help me navigate these murky waters.
First up - I'm looking at the angle handle, and I notice one of the bindable parameters is p - which I have decided stands for "pivot" since there's nothing else to tell me otherwise. If I update the "p" parameter on a node with said handle, I can see that the gadget in the viewport becomes offset from the value of the t parameter. My question is - is there a gadget connected to p that I can manipulate in the viewport?
On other handles, such as the xform, you can use the " hotkey in the viewport to enter pivot mode, but that doesn't seem to work for the angle handle.
For the above question and all future ones, I'll be attaching an example hda file. In this case I'm experimenting with the HandleDemo_Angle LOP.
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Technical Discussion » Getting a Handle on...Handles
- chendryx
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Technical Discussion » Get RAW Pixel color in COP?
- chendryx
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tamteah that's a good point!
it may be a signed 32bit integer, so half precision for negative and half for positive, in which case divide by 2 would make sense
Solaris and Karma » Create Points prim with zero sop points?
- chendryx
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jarenas
Did you get some more info from support?
Yes I did get feedback from the support team, it should have been fixed as of 18.0.802. I just tested now in 18.5.783 and it does indeed seem to be fixed.
PDG/TOPs » Nuke Server issues
- chendryx
- 86 posts
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Technical Discussion » Reference Context Option in SOP/ROP?
- chendryx
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I'm trying to figure out how to use context options in a geometry ROP, but it's not quite working the way I expect.
I'm setting the option in LOPs, and the geometry ROP is upstream in a sopcreate node, and I'm using python nodes to check that the context option has been set, however it doesn't seem to get picked up by the export nodes.
Scene attached. Pretty sure I'm doing this wrong, any pointers on the correct approach would be appreciated!
I'm setting the option in LOPs, and the geometry ROP is upstream in a sopcreate node, and I'm using python nodes to check that the context option has been set, however it doesn't seem to get picked up by the export nodes.
Scene attached. Pretty sure I'm doing this wrong, any pointers on the correct approach would be appreciated!
Edited by chendryx - July 13, 2021 16:45:25
Solaris and Karma » Create Points prim with zero sop points?
- chendryx
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Ok narrowed it down, submitted an issue to support to identify if it's truly a bug. Example file attached - it's possible to create a Mesh prim with zero points, but you can't create a Points prim from sop data with zero points.
Solaris and Karma » Create Points prim with zero sop points?
- chendryx
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Ok exploring this some more, testing with a more generic setup, it does seem like if you create an empty placeholder prim in sops, you will get a corresponding usd prim with zero points in lops.
My issue is that in my hda i am not seeing the same behavior. I'm gonna have to dig some more, see what specifically it is about my hda setup that is preventing the prim show up on the zero-point frames...
My issue is that in my hda i am not seeing the same behavior. I'm gonna have to dig some more, see what specifically it is about my hda setup that is preventing the prim show up on the zero-point frames...
Solaris and Karma » Create Points prim with zero sop points?
- chendryx
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@jsmack the solution you describe is what we ended up doing to solve the original problem where we ran into this, however that was in a specific use case where we could anticipate what prims would be created by the sop data.
I can imagine other situations where we would not be able to preempt what will be coming out of sops, and am trying to get ahead of the curve.
I can imagine other situations where we would not be able to preempt what will be coming out of sops, and am trying to get ahead of the curve.
Solaris and Karma » Create Points prim with zero sop points?
- chendryx
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I'm running into a situation where I have points in sops that i'm converting to a Points prim in lops, which should have zero points on particular frames. However, with how the lopimport works, the sopimport node doesn't create the Usd prim when there are no points.
The issue here is, now when I go to export that Points prim to a usd file, instead of having time samples on those frames where there's supposed to be zero points, it just grabs whatever points are present on the nearest frame (because of usd's interpolation).
How do I set up my sop data such that I can get a Points prim in lops with zero points? I tried using an add sop to create a ParticleSystem prim that would encapsulate the points, but that also seems to be ignored.
The issue here is, now when I go to export that Points prim to a usd file, instead of having time samples on those frames where there's supposed to be zero points, it just grabs whatever points are present on the nearest frame (because of usd's interpolation).
How do I set up my sop data such that I can get a Points prim in lops with zero points? I tried using an add sop to create a ParticleSystem prim that would encapsulate the points, but that also seems to be ignored.
Solaris and Karma » Update sopimport for custom schemas?
- chendryx
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That's what we're doing currently (custom logic), just wanted to check that there wasn't already something built-in, thanks!
Solaris and Karma » Update sopimport for custom schemas?
- chendryx
- 86 posts
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Is it possible to modify/extend the sopimport and lopimport nodes for custom in-house schemas?
Solaris and Karma » displayColor with PointInstancer in HoudiniGL?
- chendryx
- 86 posts
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Solaris and Karma » displayColor with PointInstancer in HoudiniGL?
- chendryx
- 86 posts
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I'm creating a PointInstancer with random color per instance (by copying the Cd attribute on the pointinstancer lop), and I'm able to see that color with Karma but not with Houdini GL.
Is it possible to see the displayColor with the Houdini GL renderer?
Is it possible to see the displayColor with the Houdini GL renderer?
Solaris and Karma » LopSelectionRule - I'm doing it wrong
- chendryx
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I tried scanning through the docs, but I couldn't find any explanation as to what "Read lock failed because of existing lock" either - @mtucker is there an explanation anywhere as to what that means, and/or how Houdini is handling the UsdStage such that such a warning is necessary?
Technical Discussion » config/Dialogs - how is it used?
- chendryx
- 86 posts
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I'm looking into refactoring some of our studio code, and I founds some .ds files in the config/Dialogs location, but I can't for the life of me figure out how they're used. I also saw a bunch of untyped files in the $HFS/houdini/configDialogs folder, but I couldn't open them to see what they contain.
I searched in the help docs and online, and couldn't find any references to that directory and how it's used by Houdini?
I searched in the help docs and online, and couldn't find any references to that directory and how it's used by Houdini?
Solaris and Karma » Manage Usd Prim Selection with HOM?
- chendryx
- 86 posts
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Aaaaah on the LopNetwork, I kept thinking maybe it was on the LopNode, thanks @mtucker!
Solaris and Karma » Manage Usd Prim Selection with HOM?
- chendryx
- 86 posts
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I've been scanning the docs but I can't seem to find it, how does one manage the selection stage of prims in LOPs with Python? ie how do I figure out what prims are selected, or update/manage the selections?
Technical Discussion » hou.GeometryDrawable not displaying in /obj
- chendryx
- 86 posts
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I need to update the drawable in response to a couple of different events, in particular when the user changes frames when the user clicks with the mouse. For tracking frame changes, I have to store the current frame in onEnter(), and then check in onDraw() if the frame has changed. For mouse events I can just use onMouseEvent(), but for either case, I have to keep a pointer to my SOP node and invoke cook(force=True) in order to get the drawable to update.
With GeometryDrawable I can just invoke draw(), and it handles all that neatly. I don't have to track if the frame has changed, nor do i have to keep a pointer to my sop node in order to force cook it.
With GeometryDrawable I can just invoke draw(), and it handles all that neatly. I don't have to track if the frame has changed, nor do i have to keep a pointer to my sop node in order to force cook it.
Technical Discussion » hou.GeometryDrawable not displaying in /obj
- chendryx
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hm, SimpleDrawable is a reasonable workaround for the time being (thanks for the suggestion), but there are some issues that would still require using GeometryDrawable ultimately, specifically the ability to set the drawMode to Face (ie Simple's options of Wireframe or Current do not suffice), and having the ability to control when the object re-draws.
Technical Discussion » hou.GeometryDrawable not displaying in /obj
- chendryx
- 86 posts
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The geometry is defined within the sopnet of the /obj node. I sent this directly to support and it was filed as a bug - #105955
If you want to see for yourself, I've attached two example hda's to this post - one is in SOPs and the other in OBJ - they both define their own view state that do exactly the same thing, but the /obj one is clearly incorrect in terms of what's being drawn in the viewport.
If you want to see for yourself, I've attached two example hda's to this post - one is in SOPs and the other in OBJ - they both define their own view state that do exactly the same thing, but the /obj one is clearly incorrect in terms of what's being drawn in the viewport.
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