How can i render OVER video footage

# 1 01-04-2004 , 03:28 PM

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OK, sounds easy to me... but i can't figure it out

this is what i want to do, I have created a car, i've animated it and got it to do exactly what i want, i have camera's set up in the correct places and i can render the scene BUT i want to render it over some video footage of a road, how do i do it, i have tried to render it and then overlay it but it doesn't like it and i end up with it looking very dodgey...

help?

thanks in advance

Andy

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# 2 01-04-2004 , 06:30 PM

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i think u should have shot the footage before setting up the camera's for the car shot u want to render.
then u should have imported the avi live fottage into maya.
and if u have maya live it can be very easy to do. if not, u can just match the footage with ur car render on an image plane

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# 3 01-04-2004 , 07:17 PM

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I thingk you are talking about rotoscoping, might want to do a search on that subject.

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# 4 01-04-2004 , 09:19 PM

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Maya Live should work. You might want to composit it using After Effects.

Speak to Izzy, he should be of some help user added image

Yeah, but no but yeah but no....

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# 5 02-04-2004 , 12:41 AM

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well, great stuff, i'm glad people actually take these threads seriously, I'll take a little time to explain that i've only been using maya for about a month and everything i have learned to do is basically trail and error so i know next to nothing of lingo, when you talk about maya live i am not really sure what you mean, I think i will talk to izzy... thanks for all your help and hopefully i'll bee ableto contribute somday too... peace out

Andy D

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# 6 02-04-2004 , 08:18 AM

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The steps (regardless from the fact that you use Maya live or AE) should be:

1 Shot the live video (this should really be the first step)
2 Create the model (you have already done)
3 Using the live video adjust in maya scene: scale, lighting and animation of the model (Maya live is useful, but you can do without it)
4 Render the animation.

If you wish, you could create the model before shooting the video, but you must do point 3 before rendering.

You can render using the live video as background, so the final result is already composed, or (better) render only the car and compose it later. In the last case you have really much more control over your composition and you can adjust many parameters without rendering again.

Bye!!

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# 7 02-04-2004 , 08:42 AM

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ok:

If you have a locked off shot (the camera doesnt move) then bring the first frame of your movie as an image plane. Then make a plane in maya (which represents your ground) and align it so that it matches the road in your movie. It's important that you check your focal lengths etc so that you can match the perspective of the shot.

Then you need to think about lighting your shot, I'm not even going to try and explain this here but it's not a case of simply lighting it any old way. You have to match the lighting of the background plate.

Then you need to render the car out with an alpha channel so that you dont need to rotoscope it. So render as a tiff file format. Use render layers so that you can pull a shadow pass from the ground plane.

Then bring it in to after effects or shake etc and overlay the cg stuff with the real stuff. This is a whole other topic in itself. Then tweak your cg stuff, match the grain on the plate etc etc and THEN render the plate and the cg stuff as one.

This is a really complicated subject with lots to do so take it one piece at a time.
Alan

Technical Director - Framestore

Currently working on: Your Highness

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# 8 07-04-2004 , 01:38 AM

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People,

Thank you all for your time, I have now grasped the idea, basically, and i think for the time being i will be sticking with locked off shots where i choose to use CG as i suspect then once i start moving the camera things will get pretty complicated all of a suddon, but the tips are all relevant and i will put thgem to good use.

as a point, because this really winds me up... exactly how much memory does your average animator use in his/her computer to get a nice consistant computer speed while createing your models etc?

my computer tends to slow up when my models become intricate, can be a bit annoying

thanks again everyone!!!

Andy

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# 9 07-04-2004 , 08:26 AM

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so use proxy models. You dont need to be animating with a full res model. You can get away with using sylinder for arms etc just make sure that the animation is applied to your high res model when you render.

Ps. 1gig RAM at home and 2 gig at work.

Technical Director - Framestore

Currently working on: Your Highness

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# 10 08-04-2004 , 11:20 AM

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ah ha..... why didn't i think of that? ok, another problem i have just encountered, bearing in mind i have had no formal training (so please dont be too hard on me) I have just UV mapped a texture and for the first time ever its done something completely unpredictable, what happens is that instead of my lovely image file appearing in the UV editing window so i can adjust my mapping, it seems to try and use a really low res (and crap) version of it on every face in the mapping screen, I'm pretty sure that just before this occured i pressed interactrive placement to see if it would be of any use to me, and now i can not for the life of me find a way to get it to stop doing it... very annoying, can you shed any light on this? sorry to be such an info scavinger!

as a note ( i have just read that post and it does little to illustrate whats happening) imagine you wanted to map your texture to a box, so you open it out (in the old fashioned 6 squares forming a box way) and place it over your image file.... well when i try to load my miage file instead of the whole image appearing behind my UV's, it puts a really dire pixelated version that differs slightly in each case some way, on to each seperate face.... i hope you know what i'm on about

ok!!! no need to worry... i'm a pratt and i had somehow selected 'projection' instead of 'normal' on the 2d texture selection window... all sorted!

Last edited by Andyd_79; 08-04-2004 at 11:40 AM.

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How can i render OVER video footage

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