CGTalk - Looping path animations

Gnome

05-31-2003, 10:37 PM

Unfortunately, that doesn't seem to work in this instace.
Using the curve constraint motion modifier doesn't give a graph editor curve for percentage displacement along the curve. It only allows you to designate the start and end frames for 0-100% inside the modifier panel itself.

I'm searching for an alternate means to get an object to follow a closed path, and have the capacity to set a percentage displacement along that curve exceeding 100%... so that it loops.

What other means does anyone know of for constraining an object's motion to a closed curve?

SplineGod

05-31-2003, 11:11 PM

Does your object need to deform along the path?
One thing I would try is making the spline closed before exporting it to layout.
You could also try the morph along a bone chain trick.
Another option would be to simply export the spline to layout as a motion path for your object. As a motion path you can do what digillusionist mentioned which is to set the motions to repeat.

webfox

05-31-2003, 11:32 PM

Create a spline path that you like.

Use the Path to Motion plugin in Modeler.

Load the motion under Layout: Load: Load Motion.

You may have to tell the File Requester to "view all files" if you forget to use the .mot file extension when you save out from Modeler.

Using this, you will be able to apply Repeat in the pre/post behavior.

Also, if you saved the spline you used to create your tracks for your toy train, you will automatically have the correct motion for your vehicle already to scale.

wgreenlee1

05-31-2003, 11:54 PM

"Move Path" used to work great for that but I guess it only moves the whole path and not the keyframes like the manual says.

I used to use it all the time to move keyframes.:shrug:

EDIT:...Looks like its the "Path Tool"....:shrug:

EDIT2:....well..looks like 7.5c doesnt include the stinking Path Tool.
I guess this is another Newtek flub.

Is anyone else able access the "Path TOol" in 7.5c????????????:banghead:

Gnome

06-01-2003, 12:07 AM

wa-BAM!!!! That totally did it!

The Path to Motion works good enough for me. Currently it doesn't orient the object to the path but I can fix that easily enough manually.

Thanks to everyone who offered your time and suggestions!

SplineGod

06-01-2003, 12:40 AM

Originally posted by Gnome
wa-BAM!!!! That totally did it!

The Path to Motion works good enough for me. Currently it doesn't orient the object to the path but I can fix that easily enough manually.

Thanks to everyone who offered your time and suggestions!
There should be an align to path command in there somewhere too.

webfox

06-01-2003, 01:08 AM

Currently it doesn't orient the object to the path but I can fix that easily enough manually.

Select your object.

Get your motion options for your object by pressing "m" on the keyboard.

Go to Controllers and Limits and choose "Align to Path" under Heading. (and/or pitch as need be)

Gnome

06-01-2003, 07:03 AM

This has been a tremendous help, everyone!

I'm new to Lightwave and haven't found all the bells and whistles yet - and still have lots of questions.

Here's another thought...

Let say I wanted to make a multisegmented object deform continuously around a curve similar to the train going around the track. I've discovered a few plugins with Japanese - and therefore indecypherable - manuals that promise spline based deformation, but have yet to get any promising results with them.

Does anyone have suggestions as to how you could animate an object deforming around a continuous, looping path? (like a snake chasing its tail)

Thanks in advance!

webfox

06-01-2003, 07:41 AM

The "rollercoaster" technique is a standard 3D animation problem.

There are plugins that will help you solve it, but you need to understand either the plugin or expressions to make objects obey the distance link or the frame link you need to establish.

It's a research problem and to give it would cheat you in your ability to handle problem solving. Problem solving is the number one valued trait among successful CG artists.

Check out Flay and yahoo/google for hints. Even the 3D forums for non Lightwave stuff will give you insight.

Good luck and post your product when you're done. :)

webfox

06-01-2003, 07:47 AM

Also...

http://babelfish.altavista.com is a big help in translating instructions.

Triple G

06-01-2003, 08:29 AM

Originally posted by wgreenlee1
well..looks like 7.5c doesnt include the stinking Path Tool.
I guess this is another Newtek flub.

Is anyone else able access the "Path TOol" in 7.5c????????????:banghead:

It's there...it's just not assigned a button or a keyboard shortcut by default. Why, I have no idea...:surprised

wgreenlee1

06-01-2003, 10:00 AM

Originally posted by Triple G
It's there...it's just not assigned a button or a keyboard shortcut by default. Why, I have no idea...:surprised

I dont know,its something I did probrably.....
There a few other things missing so I am going to do a repair install and see if that helps.......:cry:

webfox

06-01-2003, 05:25 PM

No, it's not your fault. It's really not assigned a button.

wgreenlee1

06-01-2003, 05:29 PM

There....
Reinstall got the Path Tool back,whew!

Gnome

06-01-2003, 08:48 PM

Back in the days when I was using Softimage, there was a great utility that allowed you to simply, and easily, create path animations and path deformations - loopable if you wished. This used one axis for translation values amounting to the percentage travel along the path you've set. Very easy to manipulate your timing using only one variable. No fiddling with world coordinates.

These other methods that I've been exploring - export path to motion for example - do not yield such finely tunable results.

I'm still searching for a simple way to:
1) animate an object around a path with only one translation curve - not just start and end frames - and have it be loopable
2) deform an object around a curve - and then animate to be loopable.

Oh man, unfortunately I'm running 7.0 and dont seem to have the Path Tool you're talking about.

webfox

06-01-2003, 10:10 PM

Is there a reason you haven't installed the update to 7.5 for free?

(not 7.5b or 7.5c... just 7.5)

(edit)
Oh and I found this... Rollercoaster/Train tutorial (http://www.newtek.com/products/lightwave/tutorials/animation/object-path/index.html)

Gnome

06-01-2003, 11:51 PM

Yeah I've poored over that tutorial as well.

Well, I think I've settled on a method that will work.

The trick here is, that anyone can come up with a complex solution to a problem, but the real juice is in simplicity. In this case, with my current knowledge of lightwave, I have to choose complexity.

I think that I'll use the Path to Motion export to drive the motion of a single unit along that path - then I can use the Cyclist plugin and a key null to modulate the percentage the unit has travelled along that path.

Does anyone know if the above solution is replicated in an easier method?

ThreeDBFX

06-02-2003, 01:20 AM

Originally posted by webfox
The "rollercoaster" technique is a standard 3D animation problem.

There are plugins that will help you solve it, but you need to understand either the plugin or expressions to make objects obey the distance link or the frame link you need to establish.

It's a research problem and to give it would cheat you in your ability to handle problem solving. Problem solving is the number one valued trait among successful CG artists.

Check out Flay and yahoo/google for hints. Even the 3D forums for non Lightwave stuff will give you insight.

Good luck and post your product when you're done. :)

Webfox, do you know the answer to his question? It seems a little f???ed up to tell some one new to this program that what they want to do is a standard, and go figure it out on their own. I thought these forums were setup so the community can share ideas and help each other, not to show others how good you are and if they struggle hard enough, they might be as good as you one day.

I just thought your reply could've been a little more helpful to the guy, that's all. We all have questions from time to time, and it would suck to have someone tell you, if I tell you that would cheat you in your ability to solve problems. Just my opinion...no hard feelings. :beer:

Gnome

06-02-2003, 01:51 AM

Not to slam webfox, but I think he misunderstood the focus of my questioning.

What I was most interested in finding at the start was a spline deformation utility that would allow looping animations, with minimal effort from the user, and not just a basic path constraint button.

Thanks everyone for all of your help.

webfox

06-02-2003, 07:12 PM

Hammish, I posted the link to the tutorial for how to do it after I said that.

To be honest, I get kinda spooked after a while in giving support in these threads. I see simple questions turn into hand holding sessions and I'm against that. We all have to learn to find resources for the standards on our own at times. The biggest part of being employable in this field is to be a problem solver.

Besides, the tutorial is online. I didn't need to type it back out again.

No hurt feelings. I like to help out... but up to a point.

And, lastly, I did feel kinda bad for holding back after Gnome pointed out that he used Softimage in the past. I didn't want to seem like the ugly 'waver. heh

Oh.. and yes, I guess I did misunderstand the question. Because spline deformation is much different that a looping path motion. Trains don't deform to match the curve of the track, they follow the path, and since you'd mentioned a train, I didn't think you were talking about a spline deformation. Sorry for the confusion.

SplineGod

06-02-2003, 07:58 PM

I was a little confused by what Gnome wanted since he was mentioning both trains and deforning along a path which are both very different things. I didnt feel like Webfox was being unhelpful either. I also agree with Webfox about being a bit leary about how much help to provide because on occassion it doesnt only turn into hand holding but people actually getting pissed off because I dont post a scene file or a tutorial (not saying anyone here did that). :)

Gnome

06-03-2003, 03:13 AM

And the ugliness of internet communication rears its head once again. If we were chatting about this over a beer there would have been no misunderstanding.

Again, thanks for all of your help!

In case you were wondering what all this fuss was about, I was searching for a simple and versatile method of animating tank treads, that would allieviate some of the difficulties inherant with the online morph-rewind-morph again methods. This is what for:

http://www.cgtalk.com/showthread.php?s=&threadid=63263

I've tried several means of accomplishing this, and being new to lightwave, I am having to plow through and make all my mistakes up front.

webfox

06-03-2003, 03:40 AM

ah.. that tutorial is here (http://www.cgfocus.com/ArticleDetails.cfm?ArticleID=118)

Gnome

06-03-2003, 03:25 PM

Yeah that's the morph-rewind-morph method, which disables your ability to do in-3d motion-blur. On the frames where the morph target rewinds you'll get a big backwards blur. Accepting that method, I have to do my track motion-blur in post.

I was trying to find a simple solution (via path deformation) to get an entire track to bend round and round the guides in a loop.

The only way I've figured to rig your treads in lightwave that would allow you to properly use motion blur is the individual track segment path-to-motion means, controlled via cyclist.

webfox

06-03-2003, 05:32 PM

It shouldn't.

Use the pre and post behavior set to "repeat". Don't do it manually.

Lightwave determines motion blur based on the last half of the movement in a frame. Repeat will reset the motion at the very beginning of the frame. In effect, the renderer will never see it reset itself for the next move.

It's used all the time to make objects repeat, cyclically, and you never see it run in reverse.

Check this mpg out. (60k) (http://hammer.prohosting.com/~cfox3d/repeat.mpg)

This is a sphere parented to a null. The null is rotated once, set to repeat and let to run for 8 cycles in this animation. You can't see any backwards blur in the whole time it runs, because that's not happening.

Gnome

06-03-2003, 10:42 PM

That's because the ball doesn't actually rewind positions. It displaces the proper amount by rewinding.

In the case of "Adrian's Tank tutorial" the treads literally move backwards when they reach the end of the cycle. Never do they complete a loop around the tread perimiter. It is a rapid sucession of very small movements forward, then immediate rewind.

webfox

06-04-2003, 11:42 AM

So what's your point? It works.

So you're saying this effect isn't good enough? (http://hammer.prohosting.com/~cfox3d/treads.mpg)

Download the tutorial and try it. They even give you the scene files. You don't have to model anything, nor do you have to set up the scene. Just move the Movement Control Null in the +X direction.

On the frames where the morph target rewinds you'll get a big backwards blur. Accepting that method, I have to do my track motion-blur in post.

What you're not understanding is that there are no *frames* where it rewinds. It rewinds between the point where it finished the final pass while rendering for the last frame and before it begins the next pass for rendering for the next frame.