Sean Lewkiw

mrCatfish

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CG Supervisor
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Canada
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Recent Forum Posts

Updating environment variables Oct. 19, 2018, 10:20 a.m.

Use “varchange”. This will update the nodes. I don't see a Python equivalent, so you'll have to use hscript.

http://www.sidefx.com/docs/houdini/commands/varchange.html [www.sidefx.com]

How to propagate a hou.NodeError to the enclosing hda Oct. 18, 2018, 3:08 p.m.

Once an HDA, go to the “Node” tab, and select the python SOP as a “Message Node”. All errors will be propogated to the top level.

Volume Light Sept. 13, 2018, 3:54 p.m.

Having some trouble with the volume light. Basically, sometimes it works, sometimes it does not work. This thing seems to be strangely black-boxed.

New Houdini, sphere, then shelf tool “explosion.” Then shelf tool “volume light”. Do a render, see some grainy lighting. Play with all parms, zero change to the look.

So I thought I'd just make sure to cache the pc sequence to disc. So I put “/tmp/cache.$F.pc” in the point cloud file parm. Render, then I look in /tmp, there is nothing there. Even closing the hip file and opening it and re-rendering, still nada.

Okay, so I turn “enable point cloud” off and on… zero visible change in renders, (not doing interactive renders).

I turn the intensity and exposure way up and way down… again, zero change.

I am also seeing lots of this in the shell:

[15:26:22] mantra: Point cloud handle referenced before it was opened.  Was pcopen() called?
[15:26:48] mantra: Point cloud handle referenced before it was opened.  Was pcopen() called?
[15:26:57] mantra: Point cloud handle referenced before it was opened.  Was pcopen() called?

So I scatter some points into the volume, (density field), save them to disc with .pc suffix, and then use those in the volume light. Repeat all of the above, no change.

The only time I can affect the look of the scene with this light is by toggling it on and off, (where I see no lights at all of course, and a really bad, grainy volume render). All other changes result in no changes to any render.

Anyone have any tips or trick on working with this thing?

Sean