Position pass for "relight" in post

[instinct]

Well technically you can store any vec3 value or any 3 floats per element.
If a Particles Birth position is available at a certain frame is over my head heh.

Regards,
Thorsten

[Mikokariadis]

Looked at the image you posted instinct and thought about an upcoming job where some heli shot footage will be tracked to insert fireworks being launched.

Think using track points for particle birth positions would be good and a world position for relight in post would be great... Great stuff.

[instinct]

Check out Nathan's reel for some awesome use of Worldpositions in nuke (for the movie 2012):

http://www.nfxplugins.com/downloads/...2009_hd720.mov

Regards,
Thorsten

[Mikokariadis]

Impressive stuff.

[sv]

MasterB; If it's a help, in Mental ray you can do this by assigning a texture to your scene using the XYZ Generator in a standard Mental Ray shader's Surface slot. Set the CoordinateSystem to 3, for World XYZ, and you can get the 'Position' pass...

[Mikokariadis]

I also read in Nathan Dunworth awesome reel that "openEXR header data contains an embedded 3d camera stored" from VRay, that along with the ZDepth pass, the Normals pass and a possible (if viable) Worldposition pass would be great together in post.

Did not know about the embedded camera info in the EXR. That would save a lot of post people going..."where is the camera export?" "are we there yet?" nag.

Did see a mental ray tutorial that states what sv just posted.

[instinct]

We add a lot of metadata to rendered EXRsequences in a postprocess to add a lot more then just camera matrix. The nice thing is that the camera will always match perfectly (different animation versions etc etc). That's a lot easier to handle then manually exporting chanfiles for nuke or whatever format your comptool needs.

Regards,
Thorsten

[Mikokariadis]

So the camera data is not embedded by default so to say? Straight out to the .exr, it is added afterwards?

[instinct]

SP3 writes camera info to the file. As we add a whole lot of more it is happening in an automatic post process that is at the same time converting the EXR to be scanline zip1.

Regards,
Thorsten

[sv]

SP3 writes camera info to the file.

how do you mean?
translation info?

[instinct]

yup as header metadata you get the following if i recall right:

Aperture
FNumber
FarClip
FarRange
FocalLength
Fov
NearClip and Range
Proection Type
Target distance

and last but not least the transformation matrix

you can view these via exrheader utility (included with OpenEXR distribution) or
in any package that allows reading of metadata (nuke will as soon as 5.2 is out) so cant really show anything but it's there and you can check it via exrheader hehe.

Regards,
Thorsten

[sv]

5.2.... right beta features!
I've been using the Nuke 'Em 2.8 script to get cameras into Nuke, works wonderfully well, but yes granted not as well as having the camera data in the rendered exr!
that's pretty sweet.

[instinct]

Well we read it with a custom camera so it's not a 5.2 feature exactly, tho that doesnt help others much i'm afraid :P It works similar as the EXRCamera Nathan shows in his real, just with a lot less features heh

Regards,
Thorsten

[Paul Oblomov]

Slight offtop - anyone of you nuke users can tell me - if there any online courses for nuke, starting from basic interface etc... ?

Just being curious about new nuke6, along with fusion6...

[instinct]

by "online course" i assume you mean free ?

If you wanna get into nuke i seriously recommend throb's "Introduction to nuke" and "Nuke in production" (both gnomon). They ive an invaluable introduction to the concepts and the "lingo". We got them both here and it's the first what we hand to both newbies and "sidegraders".

As for nuke6, that will still take a bit. 5.2 first (due out soon) and then 6 will take a while i'd assume.

Regards,
Thorsten