anyone got any advice on doing stuff like whats been seen in big holywood studios (ex. jurassic park: a dinosaur walks behind a tree then eats from another tree)

A lot... But the question is too vague. I think you need to be more specific O_o

go at it on a shot by shot basis. so if you need a shot of a dinosaur eating from a tree, while partiall y obscured by another tree, you would break that down into elements and composite them in post.

my biggest concer is matching shot angles and lighting ( i was thinking making an HDRI would work)

personally, i would consider hdri over-the-top unless you knew for certain it was going to help sell the shot. meaning, if your animation is flawless and compositing was primo, hdri could really add to it. but if all those suck then hdri would simply be a bow tie on a turd, know what i mean?

jc, I reckon, aside from minor procedural details, if one is trying to duplicate "jurassic park" shots, it's not a one-man job. there is a really huge amount of software, equipment, experience and experimentation required to get a realistic shot of a dinosaur eating a tree, or whatever.

"if one is trying to duplicate "jurassic park" shots, it's not a one-man job" It could be done by one man, if that man has the time, knowledge, and tools to make it happen. Of course, don't expect one man to make an entire movie like this, but one or two shots can absolutely be possible. Highend apps like Maya, 3dsmax, XSI, etc. have what are known as compositing or matte materials. This allows you to "block" certain elements from being rendered, while still allowing them to receive/cast shadows, or to occlude other objects in the scene against a background plate. Combining this with good camera matching is key! For example, if you have a tree in your background plate, you can occlude the 3D dinosaur as he walks in front of it, making it APPEAR to the viewer that he's actually walking BEHIND it. Sounds strange, but it's cool and works well. As for lighting, IBL is the way to go for accurate results, but ONLY if you bake it as a lightmap or fake it with a lightdome. Forget about true GI/HDRI unless the shot is very brief, or you have access to a powerful renderfarm. Finally, the most useful thing you can do for matching reality with 3D is to render your 3D shot out as multiple passes. This way, when you composite them together in post, you can adjust the color, lighting, shadows, specular, etc. all seperately, and with greater ease.

Maxxx, if the tree was part of the background plate, occluding an object in motion behind it would be no easy task, and certainly isn't efficient. It works for simple composites, but you'd have to create a dummy object in the scene that matches the tree's movements exactly (imagine all the leaves and branches moving in the wind), then apply a matte material to that object in order to occlude the dino when he passes behind it. It would be easier to erase the foreground tree entirely from the background plate, and replace it with a CG tree. Another way might be to mask out the tree in a video fx editor, and place the dino layer behind it in post. Time consuming and painstaking, either way. As for lighting, I agree IBL is probably the best way to match up the overall ambience, combined with carefully placed manual lighting rig to enhance the effect. It doesn't have to be high dynamic range, but at the very least you'd need to be able to take a series of spherical photos on location to create your 360-degree light map from the scene lighting. Camera equipment for such a task is very expensive, but you can fake that part by using the "X-mas ornament" technique, which should give you around 250 degrees of environment. Then you can fill in what you need with manual lights. As Maxxx suggested, always render out in passes so you can tinker with the colors and get a more accurate composit in post.

well, thank you for the usefull advice, i dont have a dead line for what im working on, (if i did, ide never have attempted a task like this) so render times and time consumption on the modeling/ect. isnt in issuse, and if i aboslutely want quick rendering i just pay the few dollars to use a online render farm.

I think it would be much easier to composite the dinosaur and tree using a compositing software like After Effects. I don't know if Jconxtc has it though.

i have Sony Vegas, im sure that would do it.

" i have Sony Vegas, im sure that would do it"

Yikes. :- I use Vegas too, and while I'm sure compositing like this could be done with it, I'm not so sure I'd want to try! Something like AfterEffects or Combustion will definitely give you much more sophisticated control over things like masking, keying, and mattes, and result in a cleaner composite. Message edited on: 03/21/2006 21:41