photography of reflection environment (moving car) - urgent

[Sorath]

hey people.

I'm going to shoot hdr photos for an moving reflection environment tomorrow.
a street will be filmed and a cg car will be integrated into that footage, as I've never did R&D/ set supervision for car shots I need some tips& tricks from guys who did this before.

our idea was to took an hdr photo of the street and left and right side each 100 meters and stitch this together to an panorama hdr and box reflection map this in cg.
for the sky we can take one hdr ball.

any other ways/ suggestions you would do this?

[zistambus]

Hio,
I have a few more options which could be tried out,
i.e : Like you said stitch a number of pictures depending on the shot length and the speed at which youi want yr car to moove.
The more faster your car moves, the more reflections cast, and the more pictures you need. So get that clarified, and then you take a series of photographs from a tripod with accurate angle differences, and stitch them and merge ur sky too in CS3 or so and map them on a sphere. later you cld rotate teh spehere to make the moving reflects.
You could also shoot a sequence of a moving street with sky or later comp the street and sky desired together and put this reflection on ur car.

Hope this helped,
Keep us updated.

Amritaa

[zistambus]

Hi,
You could take a series of photos of ur street from a tripod at diff angles, and stitch them together.
The no. of pics to be taken would depend on the speed of ur CG car . The faster its movement, the more pics needed. You must also make sure you don't change the position of the camera.
Next is, choose a nice sky and paint it on ur stitched image.
Map your image on a sphere, this would be ur reflection and perhaps you could rotate it fr the moving reflections. Make sure that the shape of the spehere is quite huge to prevent the reflects. from looking spherical.

You could also try out shooting a sequence of the street and comp in ur desired sky footage tooo. and do the same... this will look a bit better as the reflections wont look static...and u wld have moving vehicles/cars, blinking lights etc...

Hope this helped,
Keep us Updated.
-Amritaa

[Hugh]

I was actually discussing this with a colleague a while ago....

If you can, get a reflection ball on the back of a truck and get a high dynamic range camera pointing at it. Then drive the truck down the street - you'll have your animated HDR map... Then map this motion into the motion of the car.

I've just realised that you asked this a few weeks ago - I'd love to hear how you got on and how you did it. My idea would probably give the best result, but with the most effort - I'm sure you could get a pretty good result with a lot less work.

[im.thatoneguy]

You might also consider taking 30 or 40 photos of the area and loading up something like imag emodeler (or even photoshop now) and creating a really really basic model of the area surrounding the shot.

You wouldn't need it to be terribly accurate. since the car is so curvy and anything that's not parallaxing or rushing past the car can just be your environment sphere.

[pressfurther]

hi guys I've a similar question about reflection.
The HDRI is a still image, but is there any way to shoot as a video sequence???
when you shoot with camcorder on light probe you get animated
reflection of trees.
Can you export the footage as a image sequences and map those to reflection map? or make a big ball and mapp on it so the whole scene get reflekted in that ball? which is the best way?
I found a link how to do it in studio max the guy made a special plugin,
http://www.lysator.liu.se/~zap/chrome/example.html
how about maya? please anyhelp or any idea.

Best Regards

[zistambus]

HI,
I hope u read my prev. thread.
I had mentioned abt mapping a seq. on an object...its v well possible... just check the necessary buttons, while selecting the seq.

[Hugh]

pressfurther: The problem with this is that, if you're shooting it with a DV camera, it's really not high-dynamic range to start with. If you wanted to shoot it as a movie (which I think would be a good thing, if there are lots of reflections that will need to go into the CG), then you'd have to shoot it on something high-dynamic like film or digital film.

[pressfurther]

Dear Hugh thanks for the reply.
I was thinging to shoot with dv just for reflection, just like zap made it
http://www.lysator.liu.se/~zap/chrome/example.html

here is the example on the robot head
http://www.lysator.liu.se/~zap/kidwars/intermezzo/
his reflection on the robot head are moving he shooted with mini dv.

Before I saw that i thought there will not be possible.

I'm just confuse with this techinque.

I need some help how to do it in maya?

[RobPhoboS]

Hey guys,

I tried to start a topic yesterday but it seems to have vanished but I just saw this post and it's similar to my problem.
I have a CG object/character, that is to be matchmoved into some shots, however the environment that it's in has moving objects in the background (people/cars etc).

I've made an HDR for the lighting, which is fine as the light isn't moving.
And obviously I'll need the reflections to be live, rather than a static. Someone on CGTalk suggested using a second video camera, that is locked onto the chrome ball, and I'll just have to make sure that nobody crosses the 2nd locked off camera as I film the 'backplate'. This SHOULD ensure that I get the reflections I require.

Well, thats the theory, does it sound about right ?
Is that how it's usually done 'on-set' ?

Extra info:
Software usage is = Softimage + Mental Ray
So I can use things like their mip_rayswitch_environment, mip_cameramap, mip_mirrorball, mip_matteshadow as suggested in the last pages of the 'production' pdf document = http://www.mentalimages.com/fileadm.../production.pdf
I'm not using FG or GI, just typical lightdome from the HDR and other lights.

[RobPhoboS]

I'm going to do the test today, if my results aren't too laughable, I'll upload the test to Vimeo.

[RobPhoboS]

Crikey, is actually quite tricky if your subject is moving from room to room in one take.
So mental note guys...try not to do one take !

Since I did do one take, I thought I'd test out using the mirrorball in a few different key locations but I'll find out in the next couple of hours if that worked or not !

[kinematics]

Did it work? I am curious =)