animated object with still camera

[proces2]

in this scene i have to animate a couple cars moving through it (the cars are meant to trigger the animation of the fountain).



the camera does not move it all. so, i am wondering what the strategy is for the lighting when you have the cars moving through the scene. in this rendering, i am using irrad. map for first bounce and global photon (from file) for secondary bounce. do i have to calculate the irrad. map for each frame? - will that cause flickering?

thanks in advance,
sean

[Da_elf]

well. the cars could be done on a seperate pass and comped together. just use a matte shadow

[RErender]

Yep, comping them is best I think, they can be rendered with single frame and high imap settings or direct, since they are small they will render quickly even at high settings.

[proces2]

okay. i haven't used the matte shadow before though. any chance i can get a quick rundown of how it would work?

i've used the MAX matte shadow but not the vray one. does the matte shadow get assigned to the roadway material - then i just render out a scene with the car and the roadway?

one of the cars that is moving is the lexus in the foreground. it goes around the center fountain - how can i apply a mask to make sure that it gets clipped being the central fountain?

thanks a ton for your help!
sean

[RErender]

I think it is fastest to just put a VrayMtlWrapper over a grey vraymtl, set the wrapper to "matte Surface", "alpha contribution" to -1, and turn "shadows" and "affect alpha" on, apply it to the road and the parts of the fountain that occlude the car. The fountain parts should have "cast shadow turned off unless it's shadows hit the car. you may get some double shadows from the fountain when you comp it wich can be matted but it looks like your shadows are dark enough to hide it.

[proces2]

many thanks. that is working perfectly.

[RErender]

cool

[proces2]

i am having some trouble now getting this to work for a nighttime shot. here's a still image of the scene:


what needs to be animated is the tan lexus SUV. a couple problems that i am having:
-when using the matte surface for the road, the alpha channel does not seem to pick up all the shadows from the overhead lights (there are a series of overhead vray lights simulating light from large streetlamps)
-how can i get the alpha channel to include the light coming from the headlights?

thanks,
sean