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Technical Discussion » math problem
- SvenS
- 11 posts
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Technical Discussion » math problem
- SvenS
- 11 posts
- Offline
Hello,
I've got problems with the understanding of whats going on in my network. I need to know the in and outputs of the nodes. I've attached an image of the network. Its a CVEX Shader for clouds. Is there any way to quickly check what number and what datatype is going into and gets out of a node?
I've got problems with the understanding of whats going on in my network. I need to know the in and outputs of the nodes. I've attached an image of the network. Its a CVEX Shader for clouds. Is there any way to quickly check what number and what datatype is going into and gets out of a node?
Edited by - May 25, 2011 16:10:35
Houdini Indie and Apprentice » Pyroshader and multiple scattering
- SvenS
- 11 posts
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Thank you both very much.
I was afraid of an answer like this. thx for the link to your thread tamte.
I guess multiple scattering would be render overkill anyway. I will continue to use the pyroshader because it allows me to use the forward scattering phase which is quite important for clouds.
Well I'm not too unhappy with the look of the cloud color and density at all.
The biggest problem is, in my opinion, the overall same distribution of the noise. I tried to solve that by randomize the noise amplitude for each instance. But what I need is to control a specified group of points. Lets say the bottom points of the cloud. I want to group them so that I can assign a higher amplitude of the noise.
Btw: I use a point cloud and for instancing a cloud sphere onto each point. The idea is based on a file from odforce: http://forums.odforce.net/index.php?/topic/12923-pyroclastic-noise-demystified [forums.odforce.net]
If someone wants to see, heres my file. And also two improved renderings.
Any suggestions are welcome.
sven
I was afraid of an answer like this. thx for the link to your thread tamte.
I guess multiple scattering would be render overkill anyway. I will continue to use the pyroshader because it allows me to use the forward scattering phase which is quite important for clouds.
Well I'm not too unhappy with the look of the cloud color and density at all.
The biggest problem is, in my opinion, the overall same distribution of the noise. I tried to solve that by randomize the noise amplitude for each instance. But what I need is to control a specified group of points. Lets say the bottom points of the cloud. I want to group them so that I can assign a higher amplitude of the noise.
Btw: I use a point cloud and for instancing a cloud sphere onto each point. The idea is based on a file from odforce: http://forums.odforce.net/index.php?/topic/12923-pyroclastic-noise-demystified [forums.odforce.net]
If someone wants to see, heres my file. And also two improved renderings.
Any suggestions are welcome.
sven
Houdini Indie and Apprentice » Pyroshader and multiple scattering
- SvenS
- 11 posts
- Offline
Houdini Indie and Apprentice » Pyroshader and multiple scattering
- SvenS
- 11 posts
- Offline
Hello,
I try to use the Pyroshader for cumulus clouds because it has multiple scattering integrated. But I think I must be doing something wrong because it looks the same with or without ‘multiple scattering’ checked in the shader.
What I am doing: create a pyro shader, assign the pyro1 to my geometry, set the smoke density to .6 and the scattering phase to forward (.3). It renders nicely - but much slower than the usual billowysmoke, but thats not the case here.
Then I activate ‘scattering’ in the scattering tab. I choose a stepsize 10 times the volume step size. In my case thats 3. The camera sees the whole volume.
Then I generate the points and check them with a file node to be sure they are generated.
But when rendering no subsurface scattering is visible at all. I tried to use the ‘color correction’ and choose to tint it pure red to see if theres any difference - but there isnt.
best,
sven
I try to use the Pyroshader for cumulus clouds because it has multiple scattering integrated. But I think I must be doing something wrong because it looks the same with or without ‘multiple scattering’ checked in the shader.
What I am doing: create a pyro shader, assign the pyro1 to my geometry, set the smoke density to .6 and the scattering phase to forward (.3). It renders nicely - but much slower than the usual billowysmoke, but thats not the case here.
Then I activate ‘scattering’ in the scattering tab. I choose a stepsize 10 times the volume step size. In my case thats 3. The camera sees the whole volume.
Then I generate the points and check them with a file node to be sure they are generated.
But when rendering no subsurface scattering is visible at all. I tried to use the ‘color correction’ and choose to tint it pure red to see if theres any difference - but there isnt.
best,
sven
Houdini Indie and Apprentice » Create a Shortcut to start a new render
- SvenS
- 11 posts
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Houdini Indie and Apprentice » Create a Shortcut to start a new render
- SvenS
- 11 posts
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Hello,
couldnt find anything in the forum, so heres my question.
I would like to create a shortcut to start a new render instead of going thorugh render -> start render -> mantra. How can I do that? I cant find “start render” anywhere in the Hotkey Manager.
Is it correct, that in the renderview only the raytracer is available and the micropolygon renderer is only available in MPlay?
couldnt find anything in the forum, so heres my question.
I would like to create a shortcut to start a new render instead of going thorugh render -> start render -> mantra. How can I do that? I cant find “start render” anywhere in the Hotkey Manager.
Is it correct, that in the renderview only the raytracer is available and the micropolygon renderer is only available in MPlay?
Technical Discussion » Signed Distance Field and Level-Set
- SvenS
- 11 posts
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Houdini Lounge » Creating BDSF for PBR
- SvenS
- 11 posts
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Does anybody know if the henyey-greenstein Volume BSDFs is able to do forward scattering and adding backward scattering? Because thats what the “double henyey-greenstein” does.
“The double Henyey-Greenstein phase function is the sum of two Henyey-Greenstein phase functions, one being forward scattering, and the other being backward scattering.” http://physics.nist.gov/Divisions/Div844/facilities/scatmech/html/phase.htm [physics.nist.gov]
“The double Henyey-Greenstein phase function is the sum of two Henyey-Greenstein phase functions, one being forward scattering, and the other being backward scattering.” http://physics.nist.gov/Divisions/Div844/facilities/scatmech/html/phase.htm [physics.nist.gov]
Houdini Indie and Apprentice » Creating clouds for film - workflow
- SvenS
- 11 posts
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Thank you both for your replies!
@Soothsayer: True, many workflows for clouds in feature films depend heavily on Houdini!
At the beginning of my research I thought that fluid simulations were the most common way to generate clouds. But at this stage it seems that a procedural approach is more often used. I guess fluid simulations take too much computing time and procedurals are more art-directable?
Maybe its not new to the professionals of you, but in this document http://magnuswrenninge.com/content/pubs/VolumetricMethodsInVisualEffects2010.pdf [magnuswrenninge.com] (60mb) from Siggraph 2010 some big vfx companies wrote about their workflow. Fluid simulations are rarely mentioned. The most important technique seems to be “pyroclastic displacement” or “pyroclastic noise”. Google doesnt know much about those topics
But I saw a tutorial from cmiVFX http://www.cmivfx.com/tutorials/view/280/Houdini+Fractals [cmivfx.com]. The technique is called “Custom Volumetric Displacement” but I guess its basically the same?
Levelsets seems to be the second most important thing if you deal with clouds. Are they implemented in Houdini?
Edit: found the solution for levelsets: Levelsets = IsoOffset (outputs a SDF Volume)
@Soothsayer: True, many workflows for clouds in feature films depend heavily on Houdini!
At the beginning of my research I thought that fluid simulations were the most common way to generate clouds. But at this stage it seems that a procedural approach is more often used. I guess fluid simulations take too much computing time and procedurals are more art-directable?
Maybe its not new to the professionals of you, but in this document http://magnuswrenninge.com/content/pubs/VolumetricMethodsInVisualEffects2010.pdf [magnuswrenninge.com] (60mb) from Siggraph 2010 some big vfx companies wrote about their workflow. Fluid simulations are rarely mentioned. The most important technique seems to be “pyroclastic displacement” or “pyroclastic noise”. Google doesnt know much about those topics
But I saw a tutorial from cmiVFX http://www.cmivfx.com/tutorials/view/280/Houdini+Fractals [cmivfx.com]. The technique is called “Custom Volumetric Displacement” but I guess its basically the same?
Levelsets seems to be the second most important thing if you deal with clouds. Are they implemented in Houdini?
Edit: found the solution for levelsets: Levelsets = IsoOffset (outputs a SDF Volume)
Houdini Indie and Apprentice » Creating clouds for film - workflow
- SvenS
- 11 posts
- Offline
Hello,
i'm new to this forum and new to Houdini. I'm familiar with Maya and the basics of Maya Fluid. I don't have any specific Houdini question right now. I'm looking into creating clouds and doing research how clouds are being generated for film. I'm interested in the actual workflow. In most papers or interviews people say that they used either a self written in-house tool or a combination of Houdini and Maya. For example:
“The VFX team’s first step was to bring the polygon clouds into Houdini and voxelize them,” http://www.mrxfx.com/press/31 [mrxfx.com]
I read “voxelized them in Houdini” quite often. It seems to be a commong workflow. To understand this correct: Voxelize means that the inside of the mesh will be filled with a specified amount of voxels, depending on your resolution.
Do you think its a common workflow to create clouds for feature films?
Did somebody of you created clouds which were used in a film?
What happens after voxelizing?
The animation is driven through fluid dynamics and force fields?
A voxelshader in combination with a noise is applied to render it?
Sven
i'm new to this forum and new to Houdini. I'm familiar with Maya and the basics of Maya Fluid. I don't have any specific Houdini question right now. I'm looking into creating clouds and doing research how clouds are being generated for film. I'm interested in the actual workflow. In most papers or interviews people say that they used either a self written in-house tool or a combination of Houdini and Maya. For example:
“The VFX team’s first step was to bring the polygon clouds into Houdini and voxelize them,” http://www.mrxfx.com/press/31 [mrxfx.com]
I read “voxelized them in Houdini” quite often. It seems to be a commong workflow. To understand this correct: Voxelize means that the inside of the mesh will be filled with a specified amount of voxels, depending on your resolution.
Do you think its a common workflow to create clouds for feature films?
Did somebody of you created clouds which were used in a film?
What happens after voxelizing?
The animation is driven through fluid dynamics and force fields?
A voxelshader in combination with a noise is applied to render it?
Sven
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