Thanks Hetzen. But, what do you mean by compositing? I obviously don't even understand that much.
LaFrance, there's something around here about doing something like this from XSI and it some pretty good detail. Here is what someone (JimB) gave to us for XSI. Maybe it can translate with PM somehow -
XSI to Terragen AND Terragen to XSI by JimB
Can I pipe up a bit as well?
A VFX shot breaks down into multiple elements composited together, as a rule, and what Terragen does is allow for a realistic, mostly procedural element to create a complete environment background, or part of, that does away with the need for an expensive live action or miniature shoot. It can usually be done to the Director's specification, and very importantly, it allows the Director and VFX Supervisor (and sometimes Director of Photography even) to 'tweak' the environment. That's where the procedural aspect comes in useful - you don't need to repaint a whole area, or find or shoot photos you don't have, or remodel a 3D object or practical miniature.
The ideal scenario for a shot using Terragen is when there is no live action or man-made parts that need to intermingle with the landscape, like an establishing shot, all nature, shot in the form of a flyover as an example. But I've not had a single shot yet that does that. I think that's were the big difference lies between the beautiful stills that we see (and the occasional animation) created as their own self-contained piece of artwork, and the so-called "pro" film or broadcast work (I hate that "P" word - it's a pretension - nobody dies or goes to jail if it goes wrong) where it's simply an aid to tell a more complete story, and as such needs to be combined with other storytelling elements which have to integrate temporally with other shots and their elements.
Fuzzy bit over, the practical side to exporting a mesh, and very important one, is the guesswork goes out of that integration of elements, and speeds up the pipeline. The exported terrain mesh allows for accurate shadows to be made in the other 3D app of other 3D elements, as an example, or the limits of the action and animation can be set to make sure the relationship between camera, animated elements and environment are known and set. The exported terrain mesh can also be used in most decent compositing packages (the ones that can import 3D objects) as a cue for that type of software to hide and reveal 2D elements, amongst other things. The renderer in Terragen, unfortunately, can't shade modelled 3D objects the way other 3D renderers can, simply because that's not what it's supposed to do so far. If you look at Iron Man and get your hands on the latest Cinefex, you'll realise that the surface of his armour shading isn't just reflection, displacement, colour and specular (and the other usual bits), it's also a whole new set of shading methods that had to be developed because it was realised just the above didn't pass muster any more. TG2's strength lies elsewhere and does many things that the other renderers would find difficult to do, and take up a lot of human resources to make happen which would make a shot more expensive and prohibitive. I personally think it's gonna be three years at least before Terragen2 will be able to do everything the likes of Mental Ray can do, and I'm fine with that. Any work you might see in a film that apparently does everything TG2 can currently do probably took a huge effort and is proprietary.
If you're doing work in visual effects it's normal for mulitple apps to be used for any one shot; nobody has a problem with it and everyone realises (or they should realise) that no single app can cover everything. It's also possible for a single app to have different versions tailored to different markets with differing needs, and be no worse off for it.
The Lightwave meshes can be imported directly into XSI usually (although there seems to be a few glitches on XSI's side sometimes). If I have a known camera in XSI, which I then export into TG2 (via .chan import), I can render the terrain in TG2 (as well as an ouput mesh if I want a light mesh) from that camera's POV, and bring them all back into XSI using the XSI version of the same camera as a Texture Projection Camera to project the TG2 render onto the XSI mesh. You just have to be methodical and know what you want from the outset. Alternatively, use an Ortho camera in TG2 to create an XZ texture render and slap it onto a standard (high rez) mesh of the terrain in XSI.
The thing to bear in mind is that an imported terrain mesh 1000 units square in XSI is 1000 units square in TG2. You can actually do without a special importer/exporter for locked off cameras by simply typing the camera values (rotation and translation) from one to the other, bearing in mind TG2 uses a different co-ordinate system which I can't remember offhand (Z+ becomes Z- in one or the other, etc). This applies to pretty much all 3D apps - I've done the same between Maya and XSI and even the old Softimage3D in the past; it's a breeze. It's a pain to do for animation, though, although I have done it, spending hours and hours and hours typing values per frame when no converter was available between Softimage3D and Maya (not fun at all). A unit is a unit is a unit. If a model measures 25 units in XSI, when obj'd and put into Maya or TG2 it's 25 units in those as well, and if you move the camera 12 units above it in XSI you can do the same in Maya and get the same result. The confusion starts when we begin talking metres, centimetres, inches, etc.
At least, that's how I remember it.....
