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View Full Version : how to: slow down, speed up, slow down camera motion?



hiromiito
01-11-2005, 02:32 PM
Hi guys,
I can't figure out how to do this:
I want to animate a camera on a road, which has to slow down as it approaches a road sign then accelerate again and slow down at the next road sign.
Since I have the whole path and the signs, I thought that there might be a possibility to influence the speed with those.
Expressions? I'm always postponing the day I'll start with that!!
Any ideas? That would really help!

Thanks.

Rory_L
01-11-2005, 10:02 PM
Hello Hiromiito,

When you use Curve Constrain motion modifier, the placement and frequency of nodes on the curve influences the speed of the constrained object. This simple scene shows the effect. It`s not an exact science, but you can get your camera to slow down at the lights by adding more nodes (points) to that part of the curve.

I think I`d probably just use the curve constrain plugin to get the camera`s positions along that path, then bake the motion, reduce the keys (FI`s key reducer) and move the keys along the timeline in the graph editor to get the acceleration and deceleration needed. More precise control this way.

Cheers,

R

hiromiito
01-12-2005, 03:23 AM
Thanks Rory

I'm going to try that out. Thanks for posting a scene with that!
I'm going to try to do it with motionmixer and the timewrap function (?), as well. I've been reading about cyclist too.

I'll let you know what works best for me.

Cheers

Hiromi

hiromiito
01-14-2005, 11:18 AM
Hello Hiromiito,

When you use Curve Constrain motion modifier, the placement and frequency of nodes on the curve influences the speed of the constrained object. This simple scene shows the effect. It`s not an exact science, but you can get your camera to slow down at the lights by adding more nodes (points) to that part of the curve.

I think I`d probably just use the curve constrain plugin to get the camera`s positions along that path, then bake the motion, reduce the keys (FI`s key reducer) and move the keys along the timeline in the graph editor to get the acceleration and deceleration needed. More precise control this way.

Cheers,

R

Hi Rory,

I've been trying out different things. And I've got one question for you: what is then the difference between your method and a basic one, namely importing a motion file to the camera and tweaking the channels in the graph editor?
I tried your option. I'm disturbed by the fact that the motion baker bakes on Xchannels so you can't see them in the display (white dots for frames and purple line for path).

I don't know if you get my point. But if you have any other ideas or comments, they're welcome.

Thanks

I've been checking it as well with Motionmixer. Perfect, except I'm losing the align to path...I'm going to post about that.

Rory_L
01-15-2005, 05:31 PM
I`ll have a check on Monday. Didn`t bring my dongle home with me this weekend!

I think though that any object that already has a motion modifying plugin applied will get its keys baked to X channels by default, however can`t you just change that setting in Motionbaker`s options panel?

I`d imagine that the align to path effect only gets copied to keys if you bake HPB channels as well as the XYZ ones.

>what is then the difference between your method and a basic one, namely importing a motion file to the camera and tweaking the channels in the graph editor?

Well if there is an existing motion file that takes the camera around the course where you want, but just not when you want, then of course importing it and adjusting it in the graph editor is the way to go! (But this didn`t feature in your original question)

All the best,

R

hiromiito
01-16-2005, 04:29 AM
Hi Rory,

Thanks for your comments.
Here's the way I'll go with my animation (there's one week left, and still tons of things to do!):
I'll use motionmixer because I found out how to "align to path" > a null gets the motionmixer modifier, a camera with follower modifier , follows the null with a path delay (=replaces look-ahead option). Then I get only the timewrap channel in the modifier to tweak.

Thanks for your help.

Cheers,

H

Rory_L
01-16-2005, 07:40 PM
Great stuff!
Is it copyright, or can you post a movie file? Would be nice to see the results.

Cheers,

R

hiromiito
01-17-2005, 02:19 AM
Hi Rory,

For your information (and maybe other's), I've been getting to another solution: time remapping in After Effects: I'll render my constant speed sequences and will play around in AE, since the preview is much faster and I had already plan many things to do in it.
I'll keep you updated about the results and when things get more quite, I'll try to post a sample of the finished animation. This is for a video-clip/background film for a musician, friend of mine.

Cheers,

H