Thanks! I can't believe i missed that right at the bottom!
I see that there are PhysicsCollisionAPI and PhysicsMeshCollisionAPI listed in the drop-down.
When i try to add PhysxCollisionAPI and PhysxTriangleMeshCollisionAPI in the string manually, only PhysicsCollisionAPI and PhysicsMeshCollisionAPI are listed in the schemas with PhysxCollisionAPI and PhysxTriangleMeshCollisionAPI being left out. Are we unable to specify schemas that aren't on the list?
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Solaris and Karma » Adding schemas
- wjm
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Solaris and Karma » Adding schemas
- wjm
- 39 posts
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Hi
I can see within the documentation in the Solaris glossary relating to Schema and API Schema. But is there a node within Houdini which provides the ability to add schemas to meshes?
Snippet from a usda file which only contains a box.
The apiSchemas was added by Nvidia Isaac Sim. I assume we can add this using Python but wanted to know if there were tools already for this so we're not reinventing the wheel.
edited: Sorry i didn't realise the forums didn't like lists and hide the text.
Thanks
I can see within the documentation in the Solaris glossary relating to Schema and API Schema. But is there a node within Houdini which provides the ability to add schemas to meshes?
Snippet from a usda file which only contains a box.
def Mesh "Cube" ( prepend apiSchemas = ["PhysicsCollisionAPI", "PhysxCollisionAPI", "PhysxTriangleMeshCollisionAPI", "PhysicsMeshCollisionAPI"] )
The apiSchemas was added by Nvidia Isaac Sim. I assume we can add this using Python but wanted to know if there were tools already for this so we're not reinventing the wheel.
edited: Sorry i didn't realise the forums didn't like lists and hide the text.
Thanks
Edited by wjm - Nov. 24, 2023 10:46:02
Technical Discussion » python - script to edit python module within HDA
- wjm
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took a day and a half to find this but here's the answer for others looking
import hou node = hou.selectedNodes()[0] #get node nodeTypeData= node.type().definition().sections()#dict of available info from the hda sections. pycode = node.type().definition().sections()["PythonModule"].contents() #this gets the contents on the python module node.type().definition().addSection("PythonModule","Test string goes here")#overwrite the python module here. you can use a file read in place of the string.
Edited by wjm - July 21, 2022 08:47:09
Technical Discussion » python - script to edit python module within HDA
- wjm
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Hiya
I'm looking to have a python script go into my HDA and insert lines of code within the Scripts -> PythonModule section. Is it possible to access this via python? To answer the "why would you even want to do this?" questions, i'm trying to automate a larger more complicated process which requires code within the HDA to be present.
I've been looking at hou.HDADefinition as well as hou.hda which came close as you're able to set callbacks but that's been the closest i've seen thus far.
Thanks
I'm looking to have a python script go into my HDA and insert lines of code within the Scripts -> PythonModule section. Is it possible to access this via python? To answer the "why would you even want to do this?" questions, i'm trying to automate a larger more complicated process which requires code within the HDA to be present.
I've been looking at hou.HDADefinition as well as hou.hda which came close as you're able to set callbacks but that's been the closest i've seen thus far.
Thanks
Technical Discussion » specify min max size for UV
- wjm
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Sorry my language when it comes to UVs is pretty poor. I'm still approaching UV as I do in 3D and I'm getting the idea this shouldn't be done.
So i'd like to try and simply move the UV the middle of the UDIM procedurally. my current approach was to get the center of the UV and subtract that from 0.5,0.5. like I would I if i wanted to move a point in 3D space to another point.
Before:
After:
So i'd like to try and simply move the UV the middle of the UDIM procedurally. my current approach was to get the center of the UV and subtract that from 0.5,0.5. like I would I if i wanted to move a point in 3D space to another point.
Before:
After:
Edited by wjm - Feb. 11, 2021 20:15:16
Technical Discussion » specify min max size for UV
- wjm
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OMG you are my hero i've literally been up all day working on this problem, I thought I attempted something like this earlier in the day but must have gone wrong somewhere. You are my hero!
I don't suppose you have any idea on my other problem when it comes to translating a UV into the center? I can't seem to find much info when it comes to UVing procedurally in Houdini.
I don't suppose you have any idea on my other problem when it comes to translating a UV into the center? I can't seem to find much info when it comes to UVing procedurally in Houdini.
Technical Discussion » specify min max size for UV
- wjm
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It's close but if you scale the box in X you can see it sliding a bit.
ideally, I'm hoping to try and find a way to make something like the match size node but for UVs :/ Define a min max area ultimately forming a box and have the UV try and fit inside of it.
ideally, I'm hoping to try and find a way to make something like the match size node but for UVs :/ Define a min max area ultimately forming a box and have the UV try and fit inside of it.
Technical Discussion » specify min max size for UV
- wjm
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I'm trying to make my UVs have a fixed value and scale it so it's U and V value will be between 2 numbers. Think of it like a matchSize node but for UV.
Ideally, I would have hoped that after I got the min and max size of the UV by using an attribute promote to get the min and max. that simply putting it in a fit range would solve it?
Having messaged on Discord (thanks voxelheadD for your input) one suggestion was to use relbbox to set the UV in a vertex wrangle after the uvproject.
@uv = set(relbbox(0, "uvme", @P).x, relbbox(0, "uvme", @P).z, 0);
But this causes the UV to wrap around it's self.
Additionally is there a way to move my UV to UV world center? Thanks in advance
Ideally, I would have hoped that after I got the min and max size of the UV by using an attribute promote to get the min and max. that simply putting it in a fit range would solve it?
Having messaged on Discord (thanks voxelheadD for your input) one suggestion was to use relbbox to set the UV in a vertex wrangle after the uvproject.
@uv = set(relbbox(0, "uvme", @P).x, relbbox(0, "uvme", @P).z, 0);
But this causes the UV to wrap around it's self.
Additionally is there a way to move my UV to UV world center? Thanks in advance
Houdini Lounge » Licensing problem with Video Games
- wjm
- 39 posts
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yeah i've tried looking into this as well as Houdini would be insane if it was able to operate at runtime to generate random maps or even just scatter geometry.
Found some posts here about people asking similar questions
https://www.sidefx.com/forum/topic/57186/?page=1#post-266339 [www.sidefx.com]
From all my time looking and waiting, this is the closest i've seen, only works in the editor window though
https://www.youtube.com/watch?v=J_dUTntd8lA [www.youtube.com]
Found some posts here about people asking similar questions
https://www.sidefx.com/forum/topic/57186/?page=1#post-266339 [www.sidefx.com]
From all my time looking and waiting, this is the closest i've seen, only works in the editor window though
https://www.youtube.com/watch?v=J_dUTntd8lA [www.youtube.com]
Houdini Lounge » deactivating Pyro Source
- wjm
- 39 posts
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To add i have seen forum posts like this, but again they are using volumes to subtract. wouldn't really get rid of that smoke/flame coming off the source.
https://www.sidefx.com/forum/topic/28915/?page=1#post-132698 [www.sidefx.com]
https://www.sidefx.com/forum/topic/28915/?page=1#post-132698 [www.sidefx.com]
Houdini Lounge » deactivating Pyro Source
- wjm
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So this is a much asked question and i have searched on the forums but everyone seems to suggest similar things but im hoping i might be missing a setting in the solver or source input.
So i'm trying to hide the source volume, this is the basic shelf tool explosion and as you can see on the bottom, is there source.
I've seen people suggest taking the source volume into the pyro import and subtracting the volume. Also seen using the vel field to subtract the density as well.
But i'm trying to turn off the source all together. This is about frame 51 in the sim, if you look by the source you scan see some licks of flame/smoke coming off of the source, this isnt something i would be able to remove if i'm using the sphere as the volume to subtract with. Before anyone suggests, i dont really want to use a box to cut a chunk out of the bottom of the sim as it would defeat the purpose of what i'm trying to do which is to create a texture atlas to be used in a game engine.
On the volume source i've animated the activation turn be 0 after 24 frames, i've also put a switch at the OUT_Fuel null where after frame 24 it will switch to a null, i've also keyframed the scale for fuel and temp to be 0 after frame 24 as well. Am i going around this all wrong?
Thanks in advance!
So i'm trying to hide the source volume, this is the basic shelf tool explosion and as you can see on the bottom, is there source.
I've seen people suggest taking the source volume into the pyro import and subtracting the volume. Also seen using the vel field to subtract the density as well.
But i'm trying to turn off the source all together. This is about frame 51 in the sim, if you look by the source you scan see some licks of flame/smoke coming off of the source, this isnt something i would be able to remove if i'm using the sphere as the volume to subtract with. Before anyone suggests, i dont really want to use a box to cut a chunk out of the bottom of the sim as it would defeat the purpose of what i'm trying to do which is to create a texture atlas to be used in a game engine.
On the volume source i've animated the activation turn be 0 after 24 frames, i've also put a switch at the OUT_Fuel null where after frame 24 it will switch to a null, i've also keyframed the scale for fuel and temp to be 0 after frame 24 as well. Am i going around this all wrong?
Thanks in advance!
Houdini Indie and Apprentice » cymatic pattern generation
- wjm
- 39 posts
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Wow these are great! really need to push and learn VEX.
It looks like you both took a similar fundamental approach using the same equation.
I was trying to look online for the maths behind this and was wondering if you guys had managed to find it? as you're both using the same approach or was this already something you had known before hand?
It looks like you both took a similar fundamental approach using the same equation.
I was trying to look online for the maths behind this and was wondering if you guys had managed to find it? as you're both using the same approach or was this already something you had known before hand?
Houdini Indie and Apprentice » cymatic pattern generation
- wjm
- 39 posts
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Hi everyone
I'm trying to generate cymatic patterns to then become my source for a particle sim.
Main issue is I'm not entirely sure where to start or how to achieve the effect. Has anyone tried to achieve a similar effect? Te only thing stopping me from painting the pattern or getting an image is that I need the pattern to evolve.
Thanks
I'm trying to generate cymatic patterns to then become my source for a particle sim.
Main issue is I'm not entirely sure where to start or how to achieve the effect. Has anyone tried to achieve a similar effect? Te only thing stopping me from painting the pattern or getting an image is that I need the pattern to evolve.
Thanks
Technical Discussion » Slider controlling attribute not working
- wjm
- 39 posts
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Hi everyone
I've got a slight issue and unsure where i'm going wrong.
I'm right clicking a null and going into “edit parameter interface” to create a float.
(can be seen in the image) i'm setting the name to “trans” (an attribute i created, also in the image)
when looking at the geometry spreadsheet the value of “trans” does not change. Trans is a detail attribute.
I'm using trans to control an objects transform. I know i can link the slider to the transform node but for the purposes i need it for, it needs to be an attribute.
the null controlling the attribute is at the bottom of the network.
Thanks!
I've got a slight issue and unsure where i'm going wrong.
I'm right clicking a null and going into “edit parameter interface” to create a float.
(can be seen in the image) i'm setting the name to “trans” (an attribute i created, also in the image)
when looking at the geometry spreadsheet the value of “trans” does not change. Trans is a detail attribute.
I'm using trans to control an objects transform. I know i can link the slider to the transform node but for the purposes i need it for, it needs to be an attribute.
the null controlling the attribute is at the bottom of the network.
Thanks!
Edited by wjm - Oct. 22, 2016 09:09:45
Technical Discussion » How to create controlled stream of "energy" like e
- wjm
- 39 posts
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Hey guys
I'm trying to create an energy like effect but i'm unsure where to even to start to create this effect. Would someone be able to point me into the right direction please?
Thanks
I'm trying to create an energy like effect but i'm unsure where to even to start to create this effect. Would someone be able to point me into the right direction please?
Thanks
Work in Progress » rocket smoke
- wjm
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Hey guys
I'm trying to create a rocket launch scene but i'm having slight issue getting the “look” right. I've watched a couple of nasas launch videos and the side smoke seem to evolve and get a rather random looking appearence after a short period of time and i'm unsure how to achieve this. I've tried looking at the physics behind it to understand it a bit better but haven't had any luck.
looking at the images i can tell the smoke in the middle on the ground could use a bit more disturbance to give a bit more detail to it to correct the appearance of scale. suggestions?
edit: to achieve the side smoke i'm using a sphere in the middle and pointed the normals to the side and used the normal as the source of velocity so thats why its giving that streaky effect when looking at the side rocket view image?
I'm trying to create a rocket launch scene but i'm having slight issue getting the “look” right. I've watched a couple of nasas launch videos and the side smoke seem to evolve and get a rather random looking appearence after a short period of time and i'm unsure how to achieve this. I've tried looking at the physics behind it to understand it a bit better but haven't had any luck.
looking at the images i can tell the smoke in the middle on the ground could use a bit more disturbance to give a bit more detail to it to correct the appearance of scale. suggestions?
edit: to achieve the side smoke i'm using a sphere in the middle and pointed the normals to the side and used the normal as the source of velocity so thats why its giving that streaky effect when looking at the side rocket view image?
Technical Discussion » Killing specific particles
- wjm
- 39 posts
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Hey
I'm trying to create an energy type effect and I'm having issues killing off unwanted particles. In the image you are able to make out an energy type effect with the particles already but the issue is that there are so many unwanted particles in the scene it obstructs the view of effect I'm trying to achieve.
An alternative way i have found was using the wispy smoke shelf tool and it is able to create the effect i want but the shader doesnt allow the smoke to gain “brightness” in areas of high concentration like particles do. (can be seen in the image, thats what is creating the energy type effect.) Any tips on both would be great as i might be able to get the effect i want either way.
This image is the kind of effect i'm going for
Thanks
I'm trying to create an energy type effect and I'm having issues killing off unwanted particles. In the image you are able to make out an energy type effect with the particles already but the issue is that there are so many unwanted particles in the scene it obstructs the view of effect I'm trying to achieve.
An alternative way i have found was using the wispy smoke shelf tool and it is able to create the effect i want but the shader doesnt allow the smoke to gain “brightness” in areas of high concentration like particles do. (can be seen in the image, thats what is creating the energy type effect.) Any tips on both would be great as i might be able to get the effect i want either way.
This image is the kind of effect i'm going for
Thanks
Technical Discussion » Pyro shocksave
- wjm
- 39 posts
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Hi
I'm trying to create a shock wave pyro effect where the pyro would get pushed away from the centre of the object. People have suggested a “centroid workflow” but as i'm self teaching my self houdini i can't find out how to achieve this. Some one suggested to subject the centroid from the positon and another suggestion to get the attr vop to calculate average of the boundingbox and subtract the position.
Would someone please help me out and point em in the right direction to do this? my knowledge of houdini is limited and creating this effect has stumped me for a while now.
Thanks
I'm trying to create a shock wave pyro effect where the pyro would get pushed away from the centre of the object. People have suggested a “centroid workflow” but as i'm self teaching my self houdini i can't find out how to achieve this. Some one suggested to subject the centroid from the positon and another suggestion to get the attr vop to calculate average of the boundingbox and subtract the position.
Would someone please help me out and point em in the right direction to do this? my knowledge of houdini is limited and creating this effect has stumped me for a while now.
Thanks
Houdini Learning Materials » Volume velocity pushing outwards
- wjm
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I'm attempting to create a rocket launch and using the feedback i received it was deemed best to use a velocity volume to push the smoke outwards from the source (sphere).
An example of the velocity volume method i'm using , i've turned the box into a volume setting it to vector and naming it vel. I got the option to change the direction of the velocity but i want it to push away from the centre of the object. How could i achieve this?
An example of the velocity volume method i'm using , i've turned the box into a volume setting it to vector and naming it vel. I got the option to change the direction of the velocity but i want it to push away from the centre of the object. How could i achieve this?
Technical Discussion » How to prevent pyro smoke from moving
- wjm
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Hey Guys
I'm attempting to make a rocket launch and i'm using particles (old pop net) to help birth the smoke emitted by the rocket. But as smoke does it likes to move and rise upwards but i would like the smoke to have very little movement. Currently i have an issue with the smoke wanting to expand but i would like to keep it in a column shape. I've tried using drag but the results it gives are questionable and leaves breaks in the smoke as the source moves upwards. Is there another method i could use that would prevent the smoke from breaking and reducing the amount the smoke expands?
To get to this stage i used the old pop net emit from an object moving upwards and used those particles with the bellowing smoke shelf tool.
Thanks
I'm attempting to make a rocket launch and i'm using particles (old pop net) to help birth the smoke emitted by the rocket. But as smoke does it likes to move and rise upwards but i would like the smoke to have very little movement. Currently i have an issue with the smoke wanting to expand but i would like to keep it in a column shape. I've tried using drag but the results it gives are questionable and leaves breaks in the smoke as the source moves upwards. Is there another method i could use that would prevent the smoke from breaking and reducing the amount the smoke expands?
To get to this stage i used the old pop net emit from an object moving upwards and used those particles with the bellowing smoke shelf tool.
Thanks
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