Backdate Post: Colored Smoke from Texture in Houdini

A while back I responded to a odforce post about creating smoke from a color texture:

forums.odforce.net/index.php?/topic/17565-emit-smoke-color-from-a-texture/

Here is the video with explanation.

H12.5 Colored Smoke Sim from David Lin on Vimeo.

The color is sourced from the emitter geometry into the smoke simulation via 2 custom fields add via the Container Tools > Add Field tool. The hip file is available on the forum thread.

First TD Job in Production

Hello everyone. I started at Toneplus Animation Studios a month ago. Toneplus is a growing international production team in Tokyo.
Toneplus Animation Studios

This is my first production job--my proverbial "foot-in-the-door". Needless to say, I am very excited. It's hard work, but I don't hate it. That should be a good sign.

My primary assignments are researching and developing solutions for technical issues that come up in the CG/VFX projects we do--not very descriptive, I know. I also use the Japanese skills I picked up at my last job to help this multi-national team communicate with our Japanese colleagues and clients.

I will be posting notes about my R&D activities, mostly for my own memory. It can be a little dry as I won't be able to put down any concrete details of ongoing productions or anything covered by NDA. However I hope someone else besides me will find these trivial posts useful.

-David

Naiad Test: Crashing landing

Another interesting test made with Naiad. There have been various user projects on the Naiad Forums (http://exoticmatter.zendesk.com/forums) that pipe velocity data, amongst other things created in Houdini into Naiad to affect the simulation's behavior.

I had been asked at one point to do something similar i.e. created a sculpted, deformation-based ocean wave surface, and then re-create the waves in Naiad to add water effects like Kelvin wakes and splash/foam. This is a recent test where I finally figured out how to keep pumping velocity into the ocean sim to maintain the wave forms.

The ocean surface was created with the open-source Houdini Ocean Toolkit (HOT) in Houdini 11.0.
Since this is a geometry-based solution, the velocity vectors are approximated with Houdini's Trail SOP.

The ocean surface mesh, along with the velocity vectors at each mesh point, are then converted to Naiad's EMP format then applied to the Naiad sim. I also threw in a crashing airplane for some visual interest.

This video shows the preparation and the post-process stage of the sim. The actual sim is shown in the next video.

Also, the particle colors in the viewport after the sim data is brought back to Houdini are added with a simple VOP SOP that grabbed the speed of each particle and mapped that value to a blue-to-white ramp.


Naiad Tests - Crashing landing: Houdini Flipbooks from David Lin on Vimeo.

The actual sim in Naiad:


Naiad Tests - Crashing landing: Naiad Playblasts from David Lin on Vimeo.

Naiad Test: Bunny Example

I started using Naiad since the end of 2010 in a production support capacity.

Naiad is a highly optimized fluid simulation package that can pump out massive amount of particles/volume datasets in a relatively short amount of time. It's also worthy to mentioned that Side Effect's Houdini is the best companion to wrangle the sheer quantity of data created with Naiad.

Here is one of the test run I did with it.

This is the primary/base simulation that defines the overall shape and movement of the fluid.


Naiad Tests - Bunny in Trouble: Primary Sim from David Lin on Vimeo.

This is a secondary "splash" pass that resulted in literally millions of particles in just a few hours total.


Naiad Tests - Bunny in Trouble: Splash Sim from David Lin on Vimeo.

Houdini POP to Krakatoa PRT

I wrote a python-based Houdini Particles translator for Krakatoa's PRT format.
This was done as a weekend exercise to learn Python as well as the Houdini Object Model.

2012.12.9 Update:
The link to the OTL file appears to be broken. You can find it at this public Google Drive link:
KrakatoaPRTexport.zip

---------------------
みんなさんこんばんは。Davidです。

いきなりですが、HoudiniのPython SOPのお話です。

Houdiniはパーティクルからはじめ、いろんなデータを自由に扱えるCGソフトです。
Krakatoaはバカでかい数のパーティクルをレンダリングできる3ds Maxのプラグインです。
ExportPRT SOPは、Houdiniで作ったパーティクルをKrakatoaのパーティクル形式.PRTに書き出すHoudiniノードです。
結果は上の画面のとおりです。

= インストール方法 =
このHoudini SOP (Surface OPerator)は .OTL 形式のファイルに入っています。
Windowsの場合マイ ドキュメントの下のhoudini10.0、
MacとLinuxはホームの下のhoudini10.0。
houdini10.0の中にotlというフォルダがなければ作って、krakatoaPRTv0.1.3.otlをそこにコピーします。これでHoudiniを起動するとSOP空間にExportPRTというノードが増えます。(TAB > Digital Asset > Export PRT)

= その他 =
このSOPはPythonで書かれているので、
このノードをSOP空間に出して、右クリックで Type Properties（なが〜いメニューの一番下）メニューをクリックするとソースコードが見れます。どうぞお好きに参考、改造を。もしこれで良い絵が作れたらひと言ご連絡頂ければうれしいです。（丸投げ ^_^;

= 2012.12.9 アップデート =
 OTLデータが落ちたようです。今後はGoogle Driveで公開させて頂きます：
KrakatoaPRTexport.zip
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というわけで、ブログ始めました || And so I began blogging

みんなさんこんばんは、東京でCG系サポートの仕事をしているDavidです。
自分のCGソフトの学習ログとCG関連情報を配信するためにブログを立ち上げました。
カバーしていきたい内容はHoudini、RenderManとCGソフト全般、そしてmy life。
知人の方もこれから出会う方もどうぞよろしくお願いします。

||

Good evening, everybody. David here. I work in CG software tech support in Tokyo.
I'm starting this blog to write down my CG software learning experience and to get information out to the Japanese CG community. This blog will cover Houdini, RenderMan, CG software in general, and my life in general.
I'll try to keep this bilingual, but I make no promises. ^_^