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Technical Discussion » How to attach points to an alembic animation?
- localstarlight
- 45 posts
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Technical Discussion » How to attach points to an alembic animation?
- localstarlight
- 45 posts
- Online
How can I scatter points onto an imported alembic animation in such a way that they keep the same position on the geometry throughout the animation?
Technical Discussion » Any way to render a 360/latlong flipbook?
- localstarlight
- 45 posts
- Online
I am making an animatic for a dome show which is a 360/latlong format. It's extremely high resolution, so I'd love to take advantage of the flipbook function in Houdini for the animatic, but since it uses the viewer, even when using a camera setup to be 360, the output is still a standard perspective view. So I guess there's two questions:
1. Is there any way to get the scene viewer to show the camera view in the correct perspective (spherical/latlong) instead of perspective when using that kind of camera?
2. Is there any way to use a ROP node to render the spherical/latlong frame in a low-res OpenGL-style way that is as quick as using a flipbook?
1. Is there any way to get the scene viewer to show the camera view in the correct perspective (spherical/latlong) instead of perspective when using that kind of camera?
2. Is there any way to use a ROP node to render the spherical/latlong frame in a low-res OpenGL-style way that is as quick as using a flipbook?
Houdini Lounge » How to work with freelancers with Indie licenses?
- localstarlight
- 45 posts
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We have a Houdini FX license. We need to use various freelance Houdini artists for this project, but most of whom we encounter are using the Indie license. From what I've read, there is a 'one time only offer' where you can get a bunch of .hiplc and .hdalc files converted at once when you first purchase your license, but after that there's no easy way to interchange files between the versions.
How do other studios deal with this?
We can't buy full FX licenses for every freelancer we need to use, that would be both impractical and really expensive.
How do other studios deal with this?
We can't buy full FX licenses for every freelancer we need to use, that would be both impractical and really expensive.
Houdini Lounge » HSITE variable not being picked up
- localstarlight
- 45 posts
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Are people not really using the HSITE variable?
How are other people setting up shared a shared library of HDAs between multiple computers?
How are other people setting up shared a shared library of HDAs between multiple computers?
Houdini Lounge » HSITE variable not being picked up
- localstarlight
- 45 posts
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I have the following line in my houdini.env:
In that folder I have the following structure:
Houdini_Site
-houdini19.5
--otls
--- (various HDAs in here)
However, when I load up Houdini, none of the HDAs are accessible. The HSITE variable also doesn't appear in the variables panel (Edit->Aliases and Variables...->Variables).
What am I doing wrong?
HSITE = "D:/Dropbox/Houdini_Site"
In that folder I have the following structure:
Houdini_Site
-houdini19.5
--otls
--- (various HDAs in here)
However, when I load up Houdini, none of the HDAs are accessible. The HSITE variable also doesn't appear in the variables panel (Edit->Aliases and Variables...->Variables).
What am I doing wrong?
Technical Discussion » Matrix transformations in the VEX function 'fromNDC'
- localstarlight
- 45 posts
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I was trying to use the VEX function 'fromNDC' inside a snippet wrangle in COPS, but it doesn't seem to provide the same results as when used in a point wrangle in SOPS. The documentation for 'fromNDC' warns that NDC space may not be 'well defined' in every context, so I guess I'm up against that.
I would like to perform the calculation manually in that case, but I'm not exactly sure what transformations are involved. I am trying to convert points from NDC space to camera space. I can see that one part of it is to use the camera matrix like this:
That brings the points in the correct position/rotation in the scene, but there is something missing - I'm not sure if it is a screenspace or clip space or view space or something else transformation which also needs to occur to get the same result as the 'fromNDC' function.
I have attached a project showing the two methods (1) fromNDC, and (2) the incomplete method doing it by hand.
Can anyone help me?
I would like to perform the calculation manually in that case, but I'm not exactly sure what transformations are involved. I am trying to convert points from NDC space to camera space. I can see that one part of it is to use the camera matrix like this:
matrix cam_matrix = maketransform(0, 0, cam_position, cam_rotation); @P *= cam_matrix;
That brings the points in the correct position/rotation in the scene, but there is something missing - I'm not sure if it is a screenspace or clip space or view space or something else transformation which also needs to occur to get the same result as the 'fromNDC' function.
I have attached a project showing the two methods (1) fromNDC, and (2) the incomplete method doing it by hand.
Can anyone help me?
Technical Discussion » How to pass a texture to an OpenCL kernel?
- localstarlight
- 45 posts
- Online
I would like to pass a texture into an OpenCL kernel so I can use them as lookup tables for some operations, but I can’t figure out how to do it.
Theoretically, I could turn the texture into a volume/vdb I guess, but I just want to know if there is a proper way to do it.
Anyone have any experience in this? OpenCL in Houdini seems to be one of the lesser-documented things at the moment…
Theoretically, I could turn the texture into a volume/vdb I guess, but I just want to know if there is a proper way to do it.
Anyone have any experience in this? OpenCL in Houdini seems to be one of the lesser-documented things at the moment…
Technical Discussion » Advice with Houdini Workstation build
- localstarlight
- 45 posts
- Online
I'm trying to scope out a really meaty workstation build, and would love a sense check/some advice.
We are going to be using the workstation for three main things:
1. Houdini sims (flip/pyro mainly)
2. Redshift rendering
3. Unreal Engine development
Here are the current specs of the proposed build:
My main questions concern the CPU:
- Is the clock speed of this Xeon going to be ok for this kind of work? Not sure how well it will play with Unreal Engine?
- Would a Threadripper be a better fit?
But also wondering if there are any other considerations here that I might be missing. All help massively appreciated!
We are going to be using the workstation for three main things:
1. Houdini sims (flip/pyro mainly)
2. Redshift rendering
3. Unreal Engine development
Here are the current specs of the proposed build:
- Mobo: ASUS PRO WS W790-ACE
- GPUs: ASUS 4090 x 2
- RAM: Samsung 32GB 4800 MHz ECC DDR5 Server/Workstation RAM x 8 (256Gb RAM total)
- CPU: Intel 24 Core Xeon W7-2495X
- Drive 1: Corsair MP600 PRO XT 1TB
- Drive 2: Corsair MP600 PRO XT 2TB
- Cooler: Noctua NH-U14S DX-4677
My main questions concern the CPU:
- Is the clock speed of this Xeon going to be ok for this kind of work? Not sure how well it will play with Unreal Engine?
- Would a Threadripper be a better fit?
But also wondering if there are any other considerations here that I might be missing. All help massively appreciated!
Technical Discussion » Ray intersection with VDB?
- localstarlight
- 45 posts
- Online
Given a point, a direction vector, and a fog VDB, what is the best way to find voxels intersecting along the vector? I would ideally like to be able to find the first and last intersections if possible.
I hacked together an imprecise method by turning the VDB into a mesh and then using the intersect VEX function on the geometry, but its lack of precision is not ideal.
Is there a way to do this easily?
I hacked together an imprecise method by turning the VDB into a mesh and then using the intersect VEX function on the geometry, but its lack of precision is not ideal.
Is there a way to do this easily?
Technical Discussion » Problem constructing filepath in COPS node
- localstarlight
- 45 posts
- Online
I have a set of attributes on a mesh which is different on each frame. I am trying to use COPS to write out the attributes to a texture. The points are along the X axis, and the frames are meant to be along the Y axis. I have 508 points, and 120 frames, so my texture is 508x120px.
I couldn't figure out how to read in attributes from other frames, so I cached out the geometry to a mesh sequence.
In COPS I am then using the IX parameter to determine the point number, which works fine. But I cannot seem to get a file path constructed so that it can use IY to choose which geo to read from.
What I'm trying is to construct the filepath as a string based on three parts:
Start: "F:/Path/To/The/File."
Frame: frame number
End: ".bgeo.sc"
If I set the frame number to a constant string, for example "100" then it works fine, but obviously fills the whole texture vertically with the value from frame 100. However, if I try to set the frame number from IY via a 'character to string' node (which seems like it should turn an integer into a string) then it doesn't work. See attached image for the set up.
I can't figure out what I'm doing wrong. Maybe there is a better way to do this in the first place?
I couldn't figure out how to read in attributes from other frames, so I cached out the geometry to a mesh sequence.
In COPS I am then using the IX parameter to determine the point number, which works fine. But I cannot seem to get a file path constructed so that it can use IY to choose which geo to read from.
What I'm trying is to construct the filepath as a string based on three parts:
Start: "F:/Path/To/The/File."
Frame: frame number
End: ".bgeo.sc"
If I set the frame number to a constant string, for example "100" then it works fine, but obviously fills the whole texture vertically with the value from frame 100. However, if I try to set the frame number from IY via a 'character to string' node (which seems like it should turn an integer into a string) then it doesn't work. See attached image for the set up.
I can't figure out what I'm doing wrong. Maybe there is a better way to do this in the first place?
Technical Discussion » Question about VAT and 'Split Positions into Two Textures'
- localstarlight
- 45 posts
- Online
I'm trying to bring some Vertex Animation Textures over into Playcanvas, but I can only use 8-bit textures, so I'm using the option 'Split Positions into Two Textures'. But I can't find anywhere online or in the documentation an explanation of how to take the two resultant 8-bit textures and reconstitute them into float3 positions in my shader.
Does anyone know how this works?
Does anyone know how this works?
Solaris and Karma » Solaris to Unreal Engine - Material Assignment
- localstarlight
- 45 posts
- Online
I’m also looking for an answer to this question, did anyone ever figure out how to setup proper material assignments when going from Houdini to Unreal?
Technical Discussion » Houdini Console errors
- localstarlight
- 45 posts
- Online
This has just started happening to me too, within the last couple of hours (wasn't happening this morning or yesterday).
If I update to the latest daily build, does that mean I will no longer be able to use third-party renderers (Arnold and Redshift) since they are tied to specific versions?
If I update to the latest daily build, does that mean I will no longer be able to use third-party renderers (Arnold and Redshift) since they are tied to specific versions?
Technical Discussion » How to return a license without access to the machine?
- localstarlight
- 45 posts
- Online
Technical Discussion » How to return a license without access to the machine?
- localstarlight
- 45 posts
- Online
My desktop computer has died, and I need to get the Houdini license on it released so I can put it on another machine. The documentation says that you need to return a license from the machine it's on, but I can't currently do that.
What can I do?
What can I do?
Houdini Engine for Unreal » How to bake an asset at runtime?
- localstarlight
- 45 posts
- Online
I'm trying to do the most basic thing with an HDA and I can't figure it out.
During runtime in UE5, I want to pass some values into the HDA as parameters, then cook it. I don't know the parameters until runtime, so it can't be done in the editor.
There's hardly any BP nodes you can use with a Houdini Asset BP Component, which I don't understand. There's a 'Set Float Parameter' node, which doesn't seem to do anything. If I set a value in the constructor for example, it does nothing - it still just cooks the HDA using the values in the details panel. What about other types of parameters - int/string etc.? How are you supposed to set those?
There also doesn't seem to be any way to trigger the asset to cook, at least that I can find in the editor, nor any mention of how to do that in the docs (again, that I can find).
Does Houdini Engine really require that all values for an HDA are set in the editor? It seems rather mad that you can't do stuff at runtime... but presumably I'm just missing something obvious here?
During runtime in UE5, I want to pass some values into the HDA as parameters, then cook it. I don't know the parameters until runtime, so it can't be done in the editor.
There's hardly any BP nodes you can use with a Houdini Asset BP Component, which I don't understand. There's a 'Set Float Parameter' node, which doesn't seem to do anything. If I set a value in the constructor for example, it does nothing - it still just cooks the HDA using the values in the details panel. What about other types of parameters - int/string etc.? How are you supposed to set those?
There also doesn't seem to be any way to trigger the asset to cook, at least that I can find in the editor, nor any mention of how to do that in the docs (again, that I can find).
Does Houdini Engine really require that all values for an HDA are set in the editor? It seems rather mad that you can't do stuff at runtime... but presumably I'm just missing something obvious here?
Houdini Engine for Unreal » Editor crashing when trying to add a Houdini Asset Component
- localstarlight
- 45 posts
- Online
I am trying to add a Houdini Asset Component to a BP in UE4.27 and the editor is crashing immediately when trying to do so. This is tested with a totally fresh project.
Here is the output log:
Anyone know what's going on here? Is anyone using Houdini Asset Components in 4.27 without it crashing?
Here is the output log:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x000000000000013a
UE4Editor_Engine!UWorld::IsPlayInEditor() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Engine\Private\World.cpp:6942]
UE4Editor_HoudiniEngine
UE4Editor_Core!FTicker::Tick() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Core\Private\Containers\Ticker.cpp:95]
UE4Editor!FEngineLoop::Tick() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5132]
UE4Editor!GuardedMain() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:178]
UE4Editor!GuardedMainWrapper() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:137]
UE4Editor!LaunchWindowsStartup() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:273]
UE4Editor!WinMain() [D:\Build\++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:320]
UE4Editor!__scrt_common_main_seh() [d:\agent\_work\5\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll
Anyone know what's going on here? Is anyone using Houdini Asset Components in 4.27 without it crashing?
Edited by localstarlight - March 14, 2022 12:12:21
Houdini for Realtime » Question about Project Titan
- localstarlight
- 45 posts
- Online
Project Titan is amazing, and as someone who is using both Houdini and Unreal and looking to understand more about how to use them together, it's super inspiring to see the kinds of tools which can now be made using Houdini Engine.
I'm working my way through the cable generator tutorial series, which is great, but I'm wondering whether there are plans to produce tutorial series about any of the other tools showcased in Project Titan?
Thanks for all the amazing work.
I'm working my way through the cable generator tutorial series, which is great, but I'm wondering whether there are plans to produce tutorial series about any of the other tools showcased in Project Titan?
Thanks for all the amazing work.
Technical Discussion » FBX export is adding curves to linear animation
- localstarlight
- 45 posts
- Online
I'm trying to export a simple camera animation as an FBX out of Houdini. The animation consists of keyframes for translate and rotation at the start and end of the sequence. The interpolation between them needs to be constant, so has been set to linear.
Inside the animation editor in Houdini it looks like this (only translate shown):
However, when I bring this into my game engine, I can see that easing in and out has been added to the animation data. So if I reimport the FBX back into Houdini and look again in the animation editor, it looks like this:
Why has the animation been eased during export? I can't see any settings on the FBX export menu which could explain this.
I can get around the problem by baking the animation before exporting. However, I am doing this for a web-based game engine (Playcanvas) so file size is important. Baking the animation basically triples the size of the resultant file.
I've attached a hip file.
Anyone know why this would be happening?
Inside the animation editor in Houdini it looks like this (only translate shown):
However, when I bring this into my game engine, I can see that easing in and out has been added to the animation data. So if I reimport the FBX back into Houdini and look again in the animation editor, it looks like this:
Why has the animation been eased during export? I can't see any settings on the FBX export menu which could explain this.
I can get around the problem by baking the animation before exporting. However, I am doing this for a web-based game engine (Playcanvas) so file size is important. Baking the animation basically triples the size of the resultant file.
I've attached a hip file.
Anyone know why this would be happening?
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