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Houdini Learning Materials » Convert Shop Material attribute to CD (color) attribute?
- blackpixel
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That's because Cd is a point attribute. Promote it to Primitives with Attribute Promote or switch the Group Expression to Points.
Edited by blackpixel - May 8, 2020 03:18:24
Houdini Learning Materials » Convert Shop Material attribute to CD (color) attribute?
- blackpixel
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Aaah, ok! If it's just a texture you need, then it's super easy and fast with VEX: Point VOP, (simple) Wrangle or Attribute from Map.
( see attached hip )
If writing code is not your thing, then you can comfortably stay node based in VOPs.
( see attached hip )
If writing code is not your thing, then you can comfortably stay node based in VOPs.
Houdini Learning Materials » Convert Shop Material attribute to CD (color) attribute?
- blackpixel
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If I understand you correctly, then you want to pre-process your geometry before it goes into rendering, based on something that the shader outputs?
I'm not sure there is a direct (or easy) way to evaluate the material in SOP context.
Some workaround ideas:
1. Pre-render the whole thing in low resolution, and low settings so it outputs the attribute you want to use as a mask.
Then project UVs from the camera back onto the geometry and use the rendering as a texture in a PointSOP / Wrangle.
2. If it's one of the basic projection methods you're using (ortho, polar, cylindrical) you could also bake the shader to a low resolution texture sequence on simple geometry, depending on the type. Orthographic -> Grid; Polar -> Sphere etc. If you then apply that texture to your geometry it should more or less look similar aside from anything related to light and shading, then mask your prims and points with the color or any AOVs.
This is also a pre-render, but if you have heavy geometry it might be faster.
3. Replicate the important parts of the shader, (noises etc) that you want to use for masking in a Point VOP and reference the animated parameters from the material. You'd need to keep it up to date though. Or wrap it in an HDA that works in the material and sop context with all the important logic inside, then reference animated parms.
There are some caveats if you're using P or N directly in the shader, because they are not in object space.
I'm not sure there is a direct (or easy) way to evaluate the material in SOP context.
Some workaround ideas:
1. Pre-render the whole thing in low resolution, and low settings so it outputs the attribute you want to use as a mask.
Then project UVs from the camera back onto the geometry and use the rendering as a texture in a PointSOP / Wrangle.
2. If it's one of the basic projection methods you're using (ortho, polar, cylindrical) you could also bake the shader to a low resolution texture sequence on simple geometry, depending on the type. Orthographic -> Grid; Polar -> Sphere etc. If you then apply that texture to your geometry it should more or less look similar aside from anything related to light and shading, then mask your prims and points with the color or any AOVs.
This is also a pre-render, but if you have heavy geometry it might be faster.
3. Replicate the important parts of the shader, (noises etc) that you want to use for masking in a Point VOP and reference the animated parameters from the material. You'd need to keep it up to date though. Or wrap it in an HDA that works in the material and sop context with all the important logic inside, then reference animated parms.
There are some caveats if you're using P or N directly in the shader, because they are not in object space.
Houdini Learning Materials » Can not find my houdini.env folder
- blackpixel
- 182 posts
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houdini.env is a config file inside your Documents/houdini18.0 folder.
( If it's not there, then just start Houdini and it will create everything )
But you won't be able to use RedShift with Houdini Apprentice though, since 3rd Party Rendering is not supported:
https://www.sidefx.com/products/compare/ [www.sidefx.com]
( If it's not there, then just start Houdini and it will create everything )
But you won't be able to use RedShift with Houdini Apprentice though, since 3rd Party Rendering is not supported:
https://www.sidefx.com/products/compare/ [www.sidefx.com]
Edited by blackpixel - May 6, 2020 18:23:07
Houdini Indie and Apprentice » Houdini crashed, where are the auto-saved files located?
- blackpixel
- 182 posts
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Peter Thomas
without Code how do you find the the crash file location ?
There is a $TEMP shortcut in the File Browser:
You can also install SideFX Labs, which adds a convenient “Open Crashfile” menu script:
Houdini Indie and Apprentice » how do I extrude along axis instead of normal?
- blackpixel
- 182 posts
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There are several ways:
1. make custom point normals and set the polyextrude SOP to “Point Normal” and “Existing”.
2. make a custom vector point attribute and set the polyextrude SOP to “Point Normal” and “Attribute” and enter your attribute name.
3. set distance to 0, turn on “Transform Extruded Front” and set the Transform Space to “Global”, then transform it any way you want.
Edit: tamte was faster; should have refreshed the page ^^
1. make custom point normals and set the polyextrude SOP to “Point Normal” and “Existing”.
2. make a custom vector point attribute and set the polyextrude SOP to “Point Normal” and “Attribute” and enter your attribute name.
3. set distance to 0, turn on “Transform Extruded Front” and set the Transform Space to “Global”, then transform it any way you want.
Edit: tamte was faster; should have refreshed the page ^^
Edited by blackpixel - May 2, 2020 21:09:34
Technical Discussion » making polybevel work with booleans
- blackpixel
- 182 posts
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You could also try to fake a fillet with another boolean made from its own intersection.
It's a bit hacky, but for your case it might cut it (bad pun intended).
A 4-sided polywire from the seam can work too, if you're fine with a straight bevel.
( see hip file )
It's a bit hacky, but for your case it might cut it (bad pun intended).
A 4-sided polywire from the seam can work too, if you're fine with a straight bevel.
( see hip file )
Edited by blackpixel - May 3, 2020 00:53:53
Technical Discussion » Proper use of the Peak Handle
- blackpixel
- 182 posts
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Thank you for the quick reply and the example!
Unfortunately the python state also does not attach to the geometry.
How do I modify the position and orientation of the peak handle so it's attached to point 0 like the Peak SOP does?
Unfortunately the python state also does not attach to the geometry.
How do I modify the position and orientation of the peak handle so it's attached to point 0 like the Peak SOP does?
Technical Discussion » Proper use of the Peak Handle
- blackpixel
- 182 posts
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Has anyone successfully used the peak handle in an HDA (without a peak SOP inside)?
I have set ownerop() to a wrangle inside the asset, but it looks like it only works with an actual peak sop as the owner.
Is there any more information about the ownerop() and owneropgroup() workflow or am I missing something?
It also changes position if I exit and re-enter the handle state.
There is no mention in the docs and I only found this little snippet in the HDK code:
So now I'm pretty much stuck.
I have some hacky workarounds in the back of my head, but I'd rather use it properly.
Would python viewer states be an option for this ?
I have set ownerop() to a wrangle inside the asset, but it looks like it only works with an actual peak sop as the owner.
Is there any more information about the ownerop() and owneropgroup() workflow or am I missing something?
It also changes position if I exit and re-enter the handle state.
There is no mention in the docs and I only found this little snippet in the HDK code:
// Some functions for getting and setting our owner operator information.
// The owner operator is the operator that defines what space our handles
// should appear in and what SOP/group field we should be interested in.
So now I'm pretty much stuck.
I have some hacky workarounds in the back of my head, but I'd rather use it properly.
Would python viewer states be an option for this ?
Houdini Indie and Apprentice » Grouping 1 attribute for an effect (or another proposal)
- blackpixel
- 182 posts
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Another caveat is that Mountain SOP displaces along the normal, which you most likely don't want for this type of effect.
You could generate a custom N attribute that points up to work with mountain, or…
it might be a good idea to take a deep dive into Point VOPs next, if you want more control ( see attached hip ).
You could generate a custom N attribute that points up to work with mountain, or…
it might be a good idea to take a deep dive into Point VOPs next, if you want more control ( see attached hip ).
Technical Discussion » Create Wireframe / Outline Shader (See Image)
- blackpixel
- 182 posts
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Here's another one:
A GDC talk about some neat cell shading tricks
https://www.youtube.com/watch?v=yhGjCzxJV3E [www.youtube.com]
A GDC talk about some neat cell shading tricks
https://www.youtube.com/watch?v=yhGjCzxJV3E [www.youtube.com]
Houdini Indie and Apprentice » smallest packing sphere - POINT GRID
- blackpixel
- 182 posts
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Something like this?
Set the Point Configuration to Tetrahedral and get rid of the group.
Set the Point Configuration to Tetrahedral and get rid of the group.
Technical Discussion » Nested folder in multiparm block
- blackpixel
- 182 posts
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Technical Discussion » Does Houdini need to be more performant?
- blackpixel
- 182 posts
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Btw: here's a recent example of how a too slow stroke sop led to an amazing, creative workaround:
https://ihoudini.blogspot.com/2020/01/drawing-with-wacom-in-houdini.html [ihoudini.blogspot.com]
https://ihoudini.blogspot.com/2020/01/drawing-with-wacom-in-houdini.html [ihoudini.blogspot.com]
Edited by blackpixel - April 11, 2020 11:36:12
Technical Discussion » Does Houdini need to be more performant?
- blackpixel
- 182 posts
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It's slow in your example because you are iterating over each of the 500k points instead of per variant ( check out attached hip )
The reason people stay away from these kind of threads is that they usually stem from someone's frustration, rather than the search for help. It also tends to end in heated, almost religious debates and a thread lockdown.
You really need to specify what your problem is in order to get advice.
“this thing (node/setup) is slow”
- am I doing it wrong? -> check out the docs, look in the forums, then if everything fails ask in the forums for advice
- this is the “official” way to do it, but can it be faster ? -> ask in the forums. Maybe someone has some tricks up their sleeves or there is a different way to tackle your problem.
- this thing is unexpectedly slow -> Maybe it's a bug ? check out forums, submit a bug to sidefx
- this thing is actually slow -> submit a RFE, maybe an example of a DCC that handles this in a better way
The reason people stay away from these kind of threads is that they usually stem from someone's frustration, rather than the search for help. It also tends to end in heated, almost religious debates and a thread lockdown.
You really need to specify what your problem is in order to get advice.
“this thing (node/setup) is slow”
- am I doing it wrong? -> check out the docs, look in the forums, then if everything fails ask in the forums for advice
- this is the “official” way to do it, but can it be faster ? -> ask in the forums. Maybe someone has some tricks up their sleeves or there is a different way to tackle your problem.
- this thing is unexpectedly slow -> Maybe it's a bug ? check out forums, submit a bug to sidefx
- this thing is actually slow -> submit a RFE, maybe an example of a DCC that handles this in a better way
Edited by blackpixel - April 11, 2020 12:52:44
Houdini Indie and Apprentice » Volume difference between Render view and MPlay / to Disk
- blackpixel
- 182 posts
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IPR is always using raytracing and raytrace shadows. To preview micropoly you'd have to render to MPlay.
There is a render property parameter, that you can add to your mantra to disable the forced raytraced shadows though:
vm_iprraytraceshadows -> “Always Use Raytraced Shadows in Preview Mode”
There is a render property parameter, that you can add to your mantra to disable the forced raytraced shadows though:
vm_iprraytraceshadows -> “Always Use Raytraced Shadows in Preview Mode”
Technical Discussion » Multiple HDAs sharing common base parameters interface
- blackpixel
- 182 posts
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Could the SyncNodeVersion Event Handler do the updating part for you ?
I guess you already have a version as a part of your asset name, so you'd have to bump the Version field in the type properties too to trigger it.
I guess you already have a version as a part of your asset name, so you'd have to bump the Version field in the type properties too to trigger it.
Technical Discussion » Efficient Iteration
- blackpixel
- 182 posts
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Some ideas:
- get as much static preprocessing done as possible. You'd want to avoid iterating over each leaf per frame.
- find the orientation of the leaves and replace them with points + orient attribute.
- only deform the points and copy leaves later.
- replace existing leaves with a smaller subset of variants and use packed primitives or other instancing methods.
This can free you from being too constrained to the original topology and you can optimize it even further with custom leaf geometry , packed disk primitives or point instance procedurals. Each leaf variant can also have animation etc.
- get as much static preprocessing done as possible. You'd want to avoid iterating over each leaf per frame.
- find the orientation of the leaves and replace them with points + orient attribute.
- only deform the points and copy leaves later.
- replace existing leaves with a smaller subset of variants and use packed primitives or other instancing methods.
This can free you from being too constrained to the original topology and you can optimize it even further with custom leaf geometry , packed disk primitives or point instance procedurals. Each leaf variant can also have animation etc.
Houdini Indie and Apprentice » Dot Product and VOP Noises
- blackpixel
- 182 posts
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If you want numerical control as a mask, then just feed the angle with some offsets into 2 Fit Range VOPs and multiply them. Wrap the whole thing into an HDA and you should be good. You can also modify it to use another angle instead of thickness if you need something like 30°- 60°.
The example by Konstantin Magnus gives you much nicer ramp controls though and I'd argue that you could recreate that snow image with mestela's solution:
The example by Konstantin Magnus gives you much nicer ramp controls though and I'd argue that you could recreate that snow image with mestela's solution:
Edited by blackpixel - March 28, 2020 09:05:04
Houdini Indie and Apprentice » Rigid Body Particles using UI ?
- blackpixel
- 182 posts
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This one:
But in general I'm afraid there is no Shelf Button Solution for what you want to do. The RBD Bullet Solver SOP might be the fastest way to get there without diving into DOPs. Either way you'd have to get your hands dirty one way or another
But in general I'm afraid there is no Shelf Button Solution for what you want to do. The RBD Bullet Solver SOP might be the fastest way to get there without diving into DOPs. Either way you'd have to get your hands dirty one way or another
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