View Full Version : Refracted surface replacement

05 May 2010, 09:32 AM
Hey all--

First off, really hope I'm posting this question in the right section of the forum!

Anyways, I'll hopefully be working on my first CG/live-action film very soon and I have a general compositing technique question...

We'll be doing a bunch of work with an astronaut character who will be whizzing through space with all kinds of fun CG objects for him to interact with. Obviously one really important visual element to keep in mind is the reflective glass surface of his helmet.

Elsewhere on the web, I stumbled on this production still from a film that (I'm assuming) needed to solve the same kind of problem:

So what I'm thinking here is that they did a bunch of tracking with all those markers and then composited in a CG reflective/transparent surface in place of the actual helmet glass. Am I right about this? If so, how do you think something like this could be done? I'm pretty new to CG and compositing in general -- but not at all new to the technology -- so you can be pretty technical with me if you need to be in your answer.

I'm thinking to build a very simple model of just the glass surface in Maya and work out a good shader with all the appropriate refractive/transparent properties of the glass -- and then bring that into NukeX for compositing.

Do you think it would be possible for me to work out some method for doing the glass refraction/replacement *directly* in Nuke (without even building an object in another 3D package)? I'm just very confused about how the process would go because ostensibly if I build the surface in Maya, it would need to refract *something* when it's rendering, right? Or would I be able to render out like a "refraction pass" or something like that, that I could then bring into Nuke to do the refraction for me based on the roto'ed astronaut's face?

Any and all help is greatly appreciated guys -- Thanks so much!


06 June 2010, 01:07 PM
I think I would should the guy without the object that has to reflect, then model that object in your 3D app and add your environment 360 possibly HDRi as a reflection map, and then integrate it in your live action with the help of matchmoving, that's the first thing that comes to my mind.

CGTalk Moderation
06 June 2010, 01:07 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.