New Release: Stable Noise

[Andy Nicholas]

Hi guys,

Just pinging the group to let you know that I've just commited the first release of siLib Turbulize Attribute SOP, siLib Turbulize VOP, and si_noise.h.

I've copied some of the help card here:

     https://github.com/fxnut/siLib/tree/master/build/stable_noise

What's so different about this? Why do we need another noise node? The key bit of information is at the top of that page:

Lets you add noise to an attribute using one of 5 types of FBM based noise. The range of the noise is kept consistent regardless of the values of octaves and roughness. It also avoids the issues that built-in noise nodes have for input positions located around {0, 0, 0}.

Keeping the range of noise consistent across different values octaves and roughness might not seem to be a big feature, but it's invaluable. If you try using existing Houdini Noise nodes as a force on your particles and then tweak octaves/roughness, you'll find that the particles shoot off along the x=y=z direction which gets really annoying. The nodes and Vex functions in this commit solve that problem.

The noise functions are easily accessible from Vex for easy use in your own code.

I've made available the scripts and scene that was used to generate the si_noise.h Vex file in case you want to check it out. There are no build instructions yet, so let me know if you want more information on the process. As a rough guide, just open the hip file in build/stable_noise, and click on the buttons on the final nodes to generate the noise profiles. Then you need to run the python script to generate the VEX. You'll probably need to run that external to Houdini as you need to use SciPy to do the curve fitting.

By all means try it out, but do be aware that this has not been production tested yet. Use at your own risk!

When I get a chance, I'll make a tutorial video that shows all the benefits.

Cheers,

Andy

[Jonathan Moore]

Thanks Andy, these look really useful.

I’ll dig in, test and feedback in the coming days.

jm

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[Andy Nicholas]

Cool, thanks Jonathan! Let me know how you get on.

On Monday, 15 May 2017 12:54:19 UTC+1, Jonathan Moore wrote:

Thanks Andy, these look really useful.

I’ll dig in, test and feedback in the coming days.

jm

On 15 May 2017, at 10:54, Andy Nicholas <fxnu...@gmail.com> wrote:

Hi guys,

Just pinging the group to let you know that I've just commited the first release of siLib Turbulize Attribute SOP, siLib Turbulize VOP, and si_noise.h.

I've copied some of the help card here:

     https://github.com/fxnut/siLib/tree/master/build/stable_noise

What's so different about this? Why do we need another noise node? The key bit of information is at the top of that page:

Lets you add noise to an attribute using one of 5 types of FBM based noise. The range of the noise is kept consistent regardless of the values of octaves and roughness. It also avoids the issues that built-in noise nodes have for input positions located around {0, 0, 0}.

Keeping the range of noise consistent across different values octaves and roughness might not seem to be a big feature, but it's invaluable. If you try using existing Houdini Noise nodes as a force on your particles and then tweak octaves/roughness, you'll find that the particles shoot off along the x=y=z direction which gets really annoying. The nodes and Vex functions in this commit solve that problem.

The noise functions are easily accessible from Vex for easy use in your own code.

I've made available the scripts and scene that was used to generate the si_noise.h Vex file in case you want to check it out. There are no build instructions yet, so let me know if you want more information on the process. As a rough guide, just open the hip file in build/stable_noise, and click on the buttons on the final nodes to generate the noise profiles. Then you need to run the python script to generate the VEX. You'll probably need to run that external to Houdini as you need to use SciPy to do the curve fitting.

By all means try it out, but do be aware that this has not been production tested yet. Use at your own risk!

When I get a chance, I'll make a tutorial video that shows all the benefits.

Cheers,

Andy

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[Andy Nicholas]

Hi guys,

I've got some updates on this for you. I'm hoping that these changes should bring back that warm fuzzy feeling that you used to have in ICE where you could easily apply noise to your geometry positions or attributes. With a bit of luck, this weekend I'll get a chance to record a video showing the features and how it boosts your workflow.

Anyway, here's a list of changes:

• POPs! Added a much-needed DOP node for you to add noise to particles with the new turbulence functions: siLib POP Turbulize Attribute.
  
• For the SOP and new POP nodes:
• Ability to apply noise in Add mode or Multiply mode
• Can mimic our favourite Softimage Turbulise By Range. You now have the option to remap the noise to a range or by amplitude.
• Both nodes will automatically create attributes if they don't exist already. This is really useful and will speed up your workflow a lot.
• All three turbulence nodes now have optional Bias and Gain noise shaping functions. If you don't enable them, they won't appear in the VEX code so you don't get a performance hit. (Not the case for the VOP node, but the performance hit is minimal anyway).
  
• I've created a Github pages site here: https://fxnut.github.io/siLib/ It's a work in progress and fairly minimal at the moment. For now, it's duplicating the help cards that are on the nodes. Houdini's help system really sucks at the moment for supporting HDAs as it's really buggy, so it's useful to have this information here too. I'm using https://gohugo.io to generate the static HTML. Hugo is a little clunky, but okay once you get it working. Once SideFX get these help issues sorted (like being able to link to images inside HDAs) then we can work on prettying them up.

I would regard these nodes now in Beta release and feature complete. I am open to suggestions though, so do post in this thread if you have any good ideas. I don't want to overload these nodes with features as I don't think anyone wants them to end up looking like this! But as long as it's in keeping with the basic functionality, that's cool.

Please download and test them out and give me your feedback.

Thanks guys!

Cheers,

Andy

[Andy Nicholas]

Hey folks,

I finally got round to posting the Stable Noise video on Vimeo. It's been in the works for some weeks but I had a few loose ends to tie up, plus I've been on holiday etc. You know, the usual things :)

Anyway, have a watch of this and let me know what you think. the first part shows the problems that Houdini's native noise has (if you haven't seen this for yourself already, I suspect you may be surprised at how funky some of the behaviour can be). Anyway, here's the link:

https://vimeo.com/silib/stablenoise

Assuming all is well, I'll be pushing this out on the email groups, Twitter, and the various Houdini forums.

Also, in case you haven't already seen on the lists, I've just released a Deadline submitter for Houdini. You can take a look at it here: http://www.andynicholas.com/?p=1877

Cheers,

Andy

[Tim Bolland]

Thank you Andy! For some reason I've just seen this. I'll check it out!

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[Andy Nicholas]

Hi all,

Just letting you know I've released a fix for a small bug that was preventing multiple siTurbulise VOPs being used in the same network. 

Download from GitHub for the update (https://github.com/fxnut/siLib).

Cheers,

Andy