CGTalk - 2 Propeller-related problems

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valoukh

01-23-2006, 04:44 PM

Hi, I'm trying to get my aircrafts propellor working and have two problems with which I would much appreciate help! :)

1) I have animated the propellor starting up. It's an "old-fasioned" starter; i.e, it takes a few attempts to get going, then eventually starts and continues to spin for the duration of the animation. I wanted to form a loop in the Track View. However, when I use "Parameter Curve Out-Of-Range Types" to form a loop, it loops the propeller's whole animation sequence. I just want to loop the last 4 or 5 frames, so that it keeps spinning. Is there are way to create such a loop? I'm not sure I'm doing this the correct way.

2) I want to get the propeller spinning independently of the craft, while still remaining with it in both position and orientation. To do this, I tried applying Position and Orientation constraints. The problem is, while the Position constraint works greatly, the Orientation constraint locks also the Propeller's Y-axis, and thus stops it spinning. So, I suppose I would like to know if there's a way to constrain its orientation only on the X and Z axes, or if there's simply a better way of achieving this!

Thanks in advance,
valoukh.

P.S. I understand that one option may be to use an animated texture, but for other reasons this is not an option! :(

Craiger

01-24-2006, 06:31 PM

Well, I never use the traxx, but you could just copy and paste the keyframes in the graph editor for as many cycles as you need.

As far as keeping the propeller in the right position, simply group all of the propeller parts together, and parent constrain that group to the body of your plane.

werd up.

valoukh

01-24-2006, 07:19 PM

Thanks for your reply

When I link the Propeller to the craft, I get this weird stretching. Please see the attached images for "before" and "after" shots.

Any idea what might cause this? Just for the record, the propeller is in fact now shaped like a pencil; it's not a camera trick!

Thanks very much,
valoukh.

desmondying

01-25-2006, 05:56 AM

would linking both the propeller and the body to a helper work? So you could animate the helper to move the aircraft.

valoukh

01-25-2006, 11:31 AM

Thanks for the suggestion. Unfortunately I already tried that and the same warping happened! In the end, I exported the propeller mesh as 3DS, imported it, textured it, and linked it, and it worked fine. The problem is, while it's retained its "starting up" animation, there's a keyframe at every frame, and no curve in the editor. So it's a bitch to get a loop going. Right now, I have something which I would be happy to use, so thanks for all of your suggestions!

As for the warping, I'm assuming that somewhere during the development of this project the propeller's self has been injured. Maybe I rotated it too many times. Anyway, resetting XForm just screwed up the mesh (I've never actually used this before). Also, I did try exporting it without any animation, and would have animated from scratch just to get that curve in the editor, but there was no curve. I don't know why! I tested it by creating a cube and keyframing it moving, it worked fine, and a curve was created for it. The propeller is a sick animal...

Anyway, thanks for your help! :)

valoukh.

yenvalmar

01-31-2006, 02:42 AM

if so things may animate without having any keyframes appear in the graph editor, and you mentioned you had been using trax.

to get the rotation you want, using a trax cilp, you need to create a clip containing only a 360 degree spin of the propeller, and then loop that clip. so when you create your clip set the options to only be those frames. that way it wont cycle your entire animation.

the warping is really bizaree.. have you tried deleting history?

also, why not just parent the propeller? thats pretty much what you want.. it will follow it but any additional animation you do will happen relative to the parent.

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