Christian Sirois


About Me

Technical Director
United States of America


Recent Forum Posts

Free Heightfield Ambient Occlusion Asset using OpenCL Feb. 28, 2018, 5:26 p.m.

Hi everyone,

I've been reading this forum for a while now and even asked a few questions. The response from the community is always great so I figured it was time for me to give back a little. We have some very talented people at Seasun Games and part of our pipeline involves using Houdini 16+ heightfields quite a lot. Since moving our tools from being grid base to using volumes, there is one computed datasets that we wanted to improve and it is Ambient Occlusion on the Heightfield.

In short, this dataset allows us to modulate the distribution of plants or rocks on the terrain. It was very slow to compute using traditional VEX so I set out to create an OpenCL version and I'm sharing the result today.

I have 2 main reason for this release. First, to give back to the community that I consult often and second, to share the code and the knowledge of using OpenCL in Houdini. It's not an easy language but the benefits are sometimes extraordinary.

Also, maybe some OpenCL pro on this forum will find ways of optimizing it or it's up to anyone to add features and improve the asset. In any cases, its there for you to download. The SOP contains a branch that uses OpenCL and one that uses standard VEX for comparaison.

You can download the package below

A big thanks goes out to Robert Osborne for helping me figuring this stuff out: []

I hope you find it useful.

Christian Sirois
Technical Director
Seasun Games

2 things to improve? Feb. 12, 2018, 1:14 p.m.

Thank you. I will submit these as improvement requests.

2 things to improve? Feb. 12, 2018, 12:43 p.m.


For us, Houdini coders out there, I would like to see some improvement to the code editing window (Alt-E) and the Houdini Console.

First, add some useful features to the code editing windows. Like:
- Support docking it like any other Houdini pane.
- Support creating multiple tabs.
- Add the Ctrl-Enter shortcut so we dont have to press apply every time.
- Improve auto-complete so it can list the needed arguments when typing a function.
- The Houdini VEX Editor by Paul Winex is a very good example but it's not supported a lot these days. I miss it much.
- Add fonts support.

Second, the Houdini Console is “fine” but a Houdini Console Pane is needed.
- It could have more options like a search…
- Double click on an error would go to the code line that failed.
- Would not show up as a separeted window in MS Windows.

Big new features are great but sometimes it's the little things that makes such a big difference.