#include Statement In Ifd

[kodiak]

Hi,

Anyone knows if there is a way to include a custom IFD snippet into a main render IFD file?

I tried to add it to an object as pre/post include, but unfortunately that gets folded in the main file.

Also, variations of include, ray_include..etc didn't really lead anywhere.

Explanation: there is a heavy point cloud that holds instances of objectA, B..etc. Now when I generate the IFD, the instancing gets folded out into ray_object -i -M calls (and couple of lines of transform/shader..etc data). As the instancing is not changing during the sequence (and I didn't find a way to stop Houdini to cook this per frame), what I'm trying to do is reuse the unfolded instance code in the main IFD sequence.

Just to avoid confusion: it's not the object/attribute generation that takes a long time, but actually executing (unfolding) the point instancing. Alternative ways are also welcome.

Thanks,

Andras

[Wolfwood]

Anyone knows if there is a way to include a custom IFD snippet into a main render IFD file?

I tried to add it to an object as pre/post include, but unfortunately that gets folded in the main file.

Also, variations of include, ray_include..etc didn't really lead anywhere.

Explanation: there is a heavy point cloud that holds instances of objectA, B..etc. Now when I generate the IFD, the instancing gets folded out into ray_object -i -M calls (and couple of lines of transform/shader..etc data). As the instancing is not changing during the sequence (and I didn't find a way to stop Houdini to cook this per frame), what I'm trying to do is reuse the unfolded instance code in the main IFD sequence.

Just to avoid confusion: it's not the object/attribute generation that takes a long time, but actually executing (unfolding) the point instancing. Alternative ways are also welcome.

We've fought with this in the past and there were three solutions.

- Wait for Houdini 9.

- If your data is static and your camera transforms are seperate you can 'include' all the ray_object -i calls using the "source" command. (Remember that IFD is just a subset of hscript.)

- Write a Mantra Procedural which handles all the Instancing. (Basically a Mantra Copy SOP). It makes the instancing IFD generation near instantaneous and mantra renders at same speed or a little faster. I wrote one of these a few months ago and its a huge time saver.

[kodiak]

Thanks Wolfwood, really handy to know these.

Unfortunately option 1 and option 3 are not available this time (need this in about 2 days, preferably today ).

As this case is quite optimal from this point of view, I will give option 2 a shot this weekend.

Gonna be curious to see how the next version of mantra deals with this.

Thanks again,

Andras

[Jason]

If you're desperate, you could work out a way of using another preprocessor like "cpp" or "m4" perhaps? You could put a tiny wrapper around mantra (an executable shell script ahead of the distributed mantra in the $PATH) which calls your own preprocessor first.

#!/bin/tcsh
echo "calling mantra how i want to"
$HFS/bin/mantra $*

[kodiak]

Thanks Jason.

I think Wolfwoods second method is the one I would prefer to use. (as it could be operated a bit more easily by non-technical users) Now the problem became a bit theoretical as it looks like it's going be ok speedwise..gonna give it a try, but I'm afraid Houdini9 public beta is going to be out by then

cheers,

Andras