shadows in a room
by joe jukes
on
Sep 23, 2009 at 1:18:58 pm
Hi.
I am teaching myself some animation in AE and I am stuck at what seems to be the first hurdle!
I have created a 3D room with a ceiling, floor, two side walls and a back wall.
You are looking into the room from where the front wall would be, but instead i have placed a PS file of a window cutout. I made it cast shadows only, and placed a point light behind it to cast a window shadow into the room.
Works fine! Looks cool!
Now i want to have the shadow of a character walk past the window (ie reflected into the room).
Eventually, he will come into the room, but for now, I just tried a simple keyframed position change, sort of across the light source.
Unfortunately, all this did, when i pressed play was make all the rooms walls rotate and come apart and randomly change colours.
Do i need to copy the first frame of all the room elements how i want them, then paste that onto each following keyframe?
Re: shadows in a room by joe jukes on Sep 23, 2009 at 3:04:47 pm
hi bogiesan
when you say precompose the window object with the walking person in the same comp, what do you mean.
At the moment the whole thing is in just one comp. Are you suggesting it may be better to have the room as one comp, and the window, light, and animation on a separate comp? then put them together?
could you be a little more specific please cos like i say i'm very new to this!
Re: shadows in a room by david bogie on Sep 23, 2009 at 9:34:23 pm
[joe jukes]"when you say precompose the window object with the walking person in the same comp, what do you mean. "
Ah, sorry.
Your gobo, the object in front of the light that is casting the shadows, can just as easily be a composition as it can be an object or a layer. Select the window thingy, got to layer>precompose. This will replace the window object in your timeline with a new comp. Now you're going to add your walking person to the window comp ad not to the main composition. See? the window comp will now have your window layer AND the walker in it.
Precomposing is not a no-brainer, there are some weird things that happen and it takes practice to enjoy precomposing without thinking about the operation. Precomposing, or sometimes it's called nesting, is the solution to almost every oddball layer stacking, render pipeline, and complicated effects situation.
Go slow, post often, use the AE BAsics forum, and try to be patient. I've been using AE since v1 and there are things I've never tried and tools I've never used.
