Render from file

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Greetings,
I've been playing around with Houdini for a while now and read or heard about is capabilities of generating a render file (I believe in .ifd) and that render is super fast when doing a render from file…

The question is: How do I do that?
How do I generate a IFD?
How do I render a IFD?

Please can somebody enlight me on the subject!
JR Gauthier
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jrgauthier
Greetings,
I've been playing around with Houdini for a while now and read or heard about is capabilities of generating a render file (I believe in .ifd) and that render is super fast when doing a render from file…

The question is: How do I do that?
How do I generate a IFD?
How do I render a IFD?

Please can somebody enlight me on the subject!

Hi there,

I don't know anything about including ifds in main IFD file (although from an analogy to RenderMan this should be possible :?: ), but generally speaking to render from a file, you need to setup a procedural shader called “Mantra Delayed Load” for an object you want to render like this. This shader should point to normal geometry file *.bgeo. The geo file you create from that object with all properties, shaders etc applied.

The speed of such an approach goes from two reasons:

- Houdini doesn't have to include in every IFD (thus for every frame) heavy geometry (in case of hundreds of megabytes this takes a lot of time). IFDs are small and so are easy to load by Mantra from disk.
- Such an archive geometry can have bounding box specified, thanks to which Mantra can precisely anticipate how big chunk of geometry will be seen on screen and thus has to be loaded to memory. This has significant impact on render time of course.

hope this helps,
sy.


EDIT:

I've read your post again, and I'm not really sure if you were asking about rendering geometry from a file or just rendering from a file…

Above deliberation concerns rendering geometry from file.

As to simply rendering from ifd file, all you need to do is turning on this option in Mantra ROP, Main Tab, Disk File toggle. Then render it from command line:

mantra -f my_funcy_ifd_file.ifd

(see mantra -h for full list of options)

Indeed this is noticeably faster then firing up render from GUI because of number of reasons… like problems with mplay that shouldn't exists anyway.

Note that saving your scene as a IFD file is disabled in Houdini Apprentice.

cheers,
sy.
Edited by - Jan. 30, 2008 09:07:05
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Not sure if you're using the Apprentice or not but I think IFD generation is disabled there.
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Thanks for the elaborate awnser Symek.
It really helps me to understand.

Unfortunatly, I'm using Apprentice…Apprentice HD actually, I don't know if IFD saving works in HD, do you?

That's too bad, I didn't see any clear notice about this limitation on the Apprentice page…

Thanks!
JR Gauthier
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jrgauthier
Thanks for the elaborate awnser Symek.
It really helps me to understand.

Unfortunatly, I'm using Apprentice…Apprentice HD actually, I don't know if IFD saving works in HD, do you?

That's too bad, I didn't see any clear notice about this limitation on the Apprentice page…

Thanks!

The problem is that ifd file is mostly ASCII . So SESI wouldn't have any chance to control renderings from Apprentice. This limitation is somehow implicitly included in thing like: “1 Mantra token” and “Resolution limit”.

I think you can get similar performance starting rendering from hscript or hython though - if you're really interested.

Also, I didn't try but I think that render geometry from a file (second issue covered here) can be performed in Apprentice since *.bgeo format has its non-commercial flavor.


cheers,
sy.
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Ok, so I'm totally confused now…It's alright, I'm a noobi I like to think…sadly…

The problem is that ifd file is mostly ASCII . So SESI wouldn't have any chance to control renderings from Apprentice. This limitation is somehow implicitly included in thing like: “1 Mantra token” and “Resolution limit”.

Hmmm…okaaay…. I thought it was actually possible to start a batch render on a single machine using Houdini batch and a ifd file…Or you can probably start a batch render just using a scene file?

I didn't dig into that one yet(batch render)…So I'm actually asking without knowing anything.
Also Sidefx says that if someone needs extra render token you should purchase extra HD copies…so that would make 2 rendertokens there… Anyway, I really don't want to start a debate, I'm just a bit confused.


I think you can get similar performance starting rendering from hscript or hython though - if you're really interested.
Okay so, again I have no clue what this implies. Would that be something complicated, would that be worth it?

Also, I didn't try but I think that render geometry from a file (second issue covered here) can be performed in Apprentice since *.bgeo format has its non-commercial flavor.

Ok, this I understand..yeah! This techniques seems to be really efficient when needed, I'm definetly digging into that!

Thanks for the infos Symek, It's amazing how fast people awnser on that forum, it's great!

ps: Just so you know, I'm stronger on the artistic side than technical…but I'm trying really hard here.
JR Gauthier
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jrgauthier
Or you can probably start a batch render just using a scene file?

You can do this by loading your .hip file using hbatch or hython and then issuing commands to do the render.
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Ok, thanks for your help guys!
JR Gauthier
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