ifd generation and camera archives

[Johannes Saam]

Hey houdinis, and houdettes,

I want to start a topic about ifd generation and its optimisation inside a pipeline.

My basic problem is the following,

i generate ifd`s that have taken a while doe to amazing renders... in a pipeline with not a lot of hbatch lics,.. so that time was well spent....

then you realize you messed up a parameter in your shader... got the wrong camera, etc currently for me that means re - exporting.

So my question i guess is, is there a way to link in cameras as a archive so you can swap them easily, is there something like an RiFilter? Can i change settings in a binary ifd with a tool? Would i need to change SOHO export shizzle?

I am trying to start a discussion here how small-ish studios generate ifd`s efficently and how they manage this, and how i get around being sloppy when hitting render

Looking forward to all your ideas!

Jo

[Hazoc]

I am trying to start a discussion here how small-ish studios generate ifd`s efficently and how they manage this, and how i get around being sloppy when hitting render

I'm also interested about hearing ideas. Good topic.

[Johannes Saam]

I'm also interested about hearing ideas. Good topic.

hey i am just wondering something even cooler... is it possible to open an ifd in python?! like you open a houdini hip file?! That would be amazing open the file and then get the camera ... change it and save again? Or change settings... or grow geo from points in the file or change a shader or,.... basically i wanna know if there is hou.openFile( $AWESOME/shizzle.ifd )

thanks

jo

[Hazoc]

hey i am just wondering something even cooler... is it possible to open an ifd in python?!

I suppose it would be possible to create some sort of a wrapper to neatly manipulate ifds.

It could be somethin like the Hou-module.

ifd.Camera.camera[1].setResolution(x,y)

or something like that:)

I could see this handy when trying to find optimal settings for some part of rendering. One could easily build small loops to test various parameter values within a given range ( like Wedge ROP does).

[Johannes Saam]

hey i tried the python filtering... creating of functions and run mantra.property( camera:whatever )

i can not see where to change the cameras transformation... can someboty post a more alaborate filter that does this? or that is changing complex parameters?

thanks!

[rdg]

To me this sounds like you should skip the python filter approach.

Instead of rendering the ifd with 'mantra -j 0 -f theawesome.ifd' you could pipe it through an arbitrary tool to modify it:

cameraSwitcher theawesome.ifd > mantra -j 0

[Johannes Saam]

souds good but when i ahve a binary ifd that makes that all more complex i was hoping the filtering could be used for that

thanks for your answer!

jo

[Macha]

ray_start light# {ray_transform... almost looks like a transformation matrix of the origin of the rays. It's got 16 entries with the last column being 0,0,0,1.

Could that be what you're after?

Edited March 15, 2011 by Macha

[rdg]

souds good but when i ahve a binary ifd that makes that all more complex i was hoping the filtering could be used for that

thanks for your answer!

jo

I had the impression IFD's are always ascii. Sometimes you inline bgeo, but in most cases you probably use DLAs.

But then, yeah ... might not the trick you're looking for

[Johannes Saam]

@Macha: Yes i wrote out an ascii ifd and i say this value just could not change it with a filter... any ideas!

i check again of the ifds even in binary mode have this stuff exposed ... thanks guys!

[rdg]

i check again of the ifds even in binary mode have this stuff exposed ... thanks guys!

The binary mode just causes inline geometry to be written as b(inary)geo.