Hi there,

I'm a new user to Houdini but have a long history with vfx.

I'm trying to do something whereby I bring in an image sequence into an Image Network (called “LightTexture”) I composite this a bit then use it as the texture source of an EnvLight.

When I render this it looks great; my sphere is getting light from the image network I setup.

What I want to do next, and stay within the same Houdini session is bring that render into a new Image Network (called “Composite”)

I use a Render node which seems to allow me to grab/spawn the render out I have setup (and previously have seen and liked)

My problem is that when I hit “redo Render” on that Render node (or just view the node) it renders the sphere without the “LightTexture” and seems to just be a default colour (error colour??) i.e the Render node doesn't bring in the same render as the /out/mantra_ipr viewer shows.

I hope that makes sense. I feel like there's a dependency issues in there somewhere, like, it's rendering the scene into that “Composite” network without evaluating the other image network “LightTexture”

I have read up on the Render node and it supports only .pic so my /out/mantra_ipr has .pic set as it's output format and only otherwise changed the renderer to Physically Based Rendering mode and set the output picture field to “$HIP/images/Render.`$F4`.pic” in case it needed it.

Other notes are that I haven't done a render first, I was hoping to do it all from the “Composite” network and spawn renders on demand rather than rendering the scene, then re-importing the sequence . . . as a pure exercise.

I'm using Houdini FX Apprentice 13.0.509 (is there some limitation as part of Apprentice ??)

Thanks and I hope I was clear with the problem,

Cheers,

Matt Hermans
CG Supervisor
Alt VFX

Hey Matt - just ran a quick test and looking at the console, you should see an error e.g. ‘mantra: Unable to load texture ’opimg/LightTexture/OUT1''

This is on a full license.

Hi Marty, thanks for the quick reply.

Sorry if I don't understand you completely -

I have an envLight setup with the image path set to : “opimg/VideoTexture/null1” which I got to work correctly in the render view - looks great.

I couldn't find a console window to see render stats, but maybe you meant that in trying to bring the Render back into an Image Network resulted in an error ? I still don't know why it's not working unless there's an order to the evaluation of the Image Networks ? i.e “VideoTexture” isn't being evaluated while the “Composite” is (as the Image Networks are evaluated in serial??)

I would really have liked to do this in-line : image in, composite, use at texture, render, composite, output.

I'm re-making a music video (over 7000 frames) which was done with Maya + Nuke. If I can save the incredible time in just I/O of so many frames it would be fun and I get to learn Houdini in the mean time . . .

Thanks again,

Matt

Without further testing it may be a bug - it's be worth logging it in the Support menu above - Submit Bugs.

If you need to get cracking on it, your test works in Atomkraft in Nuke.

Hi again Marty,

thanks for that. i'll explore the bug submission process.

I originally did the music video completely inside of Nuke with an envRelight node which does diffuse and specular look ups from an input normal pass. magic, but I wanted refractions/caustics etc from a Houdini render but it may not be possible.

Thanks again,

Cool as - you can also recreate the bug with an Environment Light set to ‘Enable Sky Environment Map’ in the tab Light/Sky Environment Map; this option uses a Cop network to create the environment - the same thing you are trying to do

The terminal/ console error is:
mantra: Unable to load texture ‘opobj/envlight1/sky_env_net/sky_env_map’

I've attached the .hip file for you to send in.


PS I'll have to check on caustic but AtomKraft is 3Delight inside and has reflections. The latest version can use a fantastic path tracer

NB Say g'day to Muzza in Comp at AltVfx

Thanks !

are you Marty Blumen ??

We worked together at Fuel VFX : )

Cheers, and thanks for the simple scene too !

Nice to see you here! Houdini is the rad-az. FuelVfx- good times, good times

rock on!

as an update :

unfortunately this workflow isn't supported. So i'll have to render out then import again. Somewhat misleading i guess since the Render node is there to do just that; but you can't rely on any other COP evaluations for your render.

Perhaps it's an old node that's waiting to be removed…

thanks again Marty,

ah bummer - there's a big push from users to have the Composite section of Houdini upgraded. Hopefully this can be included then.

Hey guys i just stumbled over your post on some research Good to read from yous!!!

Rock on
Jo ( Now at framestore LA )