Found 4508 posts.
Search results Show results as topic list.
Technical Discussion » worldspace vs objectspace
- jsmack
- 7803 posts
- Offline
Houdini Indie and Apprentice » Merging two BSDFs brings Noise
- jsmack
- 7803 posts
- Offline
Using compute lighting invokes the pbr engine, even in raytracing mode. The pbr shader gathers ‘f’ from hit surfaces for secondary bounces to compute indirect lighting. Without exporting ‘f’, there is nothing to be gathered, and secondary hits will render black. The first hit renders okay as the compute lighting is evaluating the ‘f’ connected to it, and only sampling lights.
It is possible to make a shader that doesn't use pbr, such as with the ‘trace’ vop or writing your own gather loop. In this case you can gather ‘Cf’ or any other export and perform light transport using your own method.
It is possible to make a shader that doesn't use pbr, such as with the ‘trace’ vop or writing your own gather loop. In this case you can gather ‘Cf’ or any other export and perform light transport using your own method.
Technical Discussion » How to get a unique ID / UUIDish thing for each object (for use as a random seed)?
- jsmack
- 7803 posts
- Offline
howiem
Houdini must use some kinda UUID-ish thing internally to refer to objects, so you can rename stuff and all the references across the scene are updated (right? Or does Houdini just do a global “search and replace” whenever you rename something?)
Nodes have an op id, but it is only unique within a given session. Reloading your scene in a new session will assign new ids. The node name is the unique identifier stored with the scene file.
One solution to your workflow that would allow renaming the nodes as you please, would be to create a shelf tool script that creates a geo node with your setup inside, and adds a spare parameter to the geo node. The script would then set the value to a random number such as with the python random module. You can drag a selection to your toolbar to create an initial tool starting point, and modify the script to add the spare parm/random number.
Edited by jsmack - April 2, 2019 13:44:46
Houdini Indie and Apprentice » Merging two BSDFs brings Noise
- jsmack
- 7803 posts
- Offline
tamteYou still refract lights, just not for the first bounce. This only works for closed (solid) figures where you can never see any direct refractions. Normal solids always require a minimum of two transmission bounces to a light source. (unless the light is inside the geometry).
how do you reflect/refract lights then?
Houdini Indie and Apprentice » Merging two BSDFs brings Noise
- jsmack
- 7803 posts
- Offline
A workaround I've used in the past that helps with the direct reflection is to disable ‘refract lights’ for the first bounce.
It doesn't help with the noise is coming from deeper bounces, however.
It doesn't help with the noise is coming from deeper bounces, however.
Houdini Indie and Apprentice » POP Mass is inverted or something?
- jsmack
- 7803 posts
- Offline
Sounds correct to me.
Remember, Force = Mass * Acceleration
A force will result in 1/2 as much acceleration for a body with 2 times the mass.
A gravity force applies an acceleration directly, the force is proportional to mass, resulting in all bodies gaining the same acceleration.
Remember, Force = Mass * Acceleration
A force will result in 1/2 as much acceleration for a body with 2 times the mass.
A gravity force applies an acceleration directly, the force is proportional to mass, resulting in all bodies gaining the same acceleration.
PDG/TOPs » No input/output on TOPs nodes
- jsmack
- 7803 posts
- Offline
I'm guessing the rather vaguely named ‘utils’ module in the pdg python repo is going to cause some widespread conflicts with other lazily named modules.
$HH/pdg/types/ is a root level python path, and thus needs to be free of conflicting names.
$HH/pdg/types/ is a root level python path, and thus needs to be free of conflicting names.
Technical Discussion » trying to pass a detail into a string giving me trouble...
- jsmack
- 7803 posts
- Offline
Houdini Indie and Apprentice » animation editor: change tangent type to one keyframe only
- jsmack
- 7803 posts
- Offline
The function type is a property of the segment, not the keyframe.
Edit, after watching your video, you are looking for a way to automatically match the tangents to the slope. I'm not sure if there is a way to do that.
Edit, after watching your video, you are looking for a way to automatically match the tangents to the slope. I'm not sure if there is a way to do that.
Edited by jsmack - March 25, 2019 14:43:57
Technical Discussion » How to create a subnet with one input and one output but multiple geometries?
- jsmack
- 7803 posts
- Offline
Ah, I see now why you wanted to merge them. As of now there is not a way to instance entire hierarchies that way.
Something I have done in the past to allow instancing of hierarchies is to export the objects to alembic. Alembic files can be read into sops as packed primitives, which allow for instancing onto points. You may need to redo shader assignments, however.
Something I have done in the past to allow instancing of hierarchies is to export the objects to alembic. Alembic files can be read into sops as packed primitives, which allow for instancing onto points. You may need to redo shader assignments, however.
Technical Discussion » Supporting multiple renderers
- jsmack
- 7803 posts
- Offline
The collect VOP is supposed to facilitate this, although it's up to the renderers to support this functionality.
Houdini Indie and Apprentice » How to create a surface around a hole
- jsmack
- 7803 posts
- Offline
Although avoiding the problem to begin with is the best solution, sometimes you just need to bridge a gap. For that there is polybridge:
Houdini Indie and Apprentice » transfer animation fromp point (position + normal) to camera?
- jsmack
- 7803 posts
- Offline
You can't control a camera from a wrangle in sops directly, but you can use a constraint to make the camera follow animation on geometry.
http://www.sidefx.com/docs/houdini/shelf/constraintpoints.html [www.sidefx.com]
http://www.sidefx.com/docs/houdini/shelf/constraintpoints.html [www.sidefx.com]
Edited by jsmack - March 25, 2019 01:44:18
Houdini Indie and Apprentice » imported .abc camera: how to access position/orientation with a wrangle? SOLVED
- jsmack
- 7803 posts
- Offline
In a separate object's pointwrangle:
(You can also object merge the point from inside the camera object into your source object. If you need the z axis, add N to the point inside the camera with a value of {0,0,-1})
string camera = "/obj/alembicarchive1/Camera2/CameraShape2"; // path to your camera @P = ptransform(camera, "space:current", {0,0,0}); @N = ntransform(camera, "space:current", {0,0,-1});
(You can also object merge the point from inside the camera object into your source object. If you need the z axis, add N to the point inside the camera with a value of {0,0,-1})
Technical Discussion » How to create a subnet with one input and one output but multiple geometries?
- jsmack
- 7803 posts
- Offline
Objects don't need to be merged, and cannot be merged. When you render your Subnet HDA object, It can be specified in either the force objects list or candidate objects list. Under candidate, all displayed objects inside the subnet will be rendered. If the subnet is listed under force, then all objects within will be rendered regardless of their display flags.
Subnet/HDA objects always only have one output, which is a transform. The source of the transform can be specified from one of the contained objects or any input object's transform.
Subnet/HDA objects always only have one output, which is a transform. The source of the transform can be specified from one of the contained objects or any input object's transform.
Edited by jsmack - March 25, 2019 01:26:20
Technical Discussion » Camera movement
- jsmack
- 7803 posts
- Offline
You could use a rivet object or point constraint on a Null to constrain the Null to the character's head. Then use that Null object as the look at object for the camera.
Houdini Indie and Apprentice » File SOP: use detail value in file's naming?
- jsmack
- 7803 posts
- Offline
The backtick is also called the ‘grave accent’ key.
I don't know what keyboard layout you use but it is in the upper left corner on a US keyboard layout.
I don't know what keyboard layout you use but it is in the upper left corner on a US keyboard layout.
Technical Discussion » Mantra black refract issue...
- jsmack
- 7803 posts
- Offline
This is an example of total internal reflection, any shader using fresnel blending will exhibit total internal reflection where no transmission is possible due to the geometry. Although the GGX bsdf has the option to disable fresnel blending, it doesn't allow transmission through total internal reflections, possible due to the microfacet model which assumes fresnel blending is taking place.
The solutions you have found to use a specular model other than GGX are the only ones available.
The solutions you have found to use a specular model other than GGX are the only ones available.
Technical Discussion » Few simple and fast questions for Houdini 17.5.
- jsmack
- 7803 posts
- Offline
Viewport volume lighting is accelerated in 17.5, you don't need to do anything to benefit. (It is the same in all editions of Houdini)
Volume simulation/computation remains unchanged from before, (OpenCL in DOPs, VEX in SOPs, etc)
Volume simulation/computation remains unchanged from before, (OpenCL in DOPs, VEX in SOPs, etc)
Technical Discussion » maximum texture size?
- jsmack
- 7803 posts
- Offline
The default resolution cap in cops is 10k. You can bump it in the prefs:
http://www.sidefx.com/docs/houdini/ref/windows/mainprefs.html#cooking [www.sidefx.com]
http://www.sidefx.com/docs/houdini/ref/windows/mainprefs.html#cooking [www.sidefx.com]
-
- Quick Links