View Full Version : Path based animation

02 February 2002, 07:25 PM
I have a simple question. Does anyone know how to create path based animation in Lightwave? In all other apps, Maya, Max, and Soft, you can create a spline curve, and then attach an object or camera to this path. Then to animate the object on this path, all you need is to key frame the translation value to the object 0% being the start of the spline and 100% being the end. This is useful when you need to control something as if it was on a track but still want to modify the pacing and timing.

Any ideas? :D

02 February 2002, 12:27 AM
-Create some points in modeler (+)
-Use those ponits for creating an open curve (crtl+p)
-Then from the file menu export path to motion.
-In layout select the item you want to have that motion and File > Load > Motion file

Hope this helps ;)

02 February 2002, 05:58 AM
That does not allow you to retime the animation while keeping the exact same curve for your path. When you use path to motion is sets its own subdivision on the keyframes, and you can't even them out, slow it doen or spped it up.

Thats what I need

02 February 2002, 06:11 AM
You can retime from the graph editor

02 February 2002, 07:53 PM
Yes but if you retime and move/scale keys in the graph you end up reshaping the slines on the curves, and your path is not the same shape that it startred as.

I can't belive that there is not a way to do somthing so fundemental in LW that very other app has been able to do for many many years. Theres got to be a way.

02 February 2002, 02:01 AM
Seems to work just fine when I use it. You can easily scale the timing using the graph editor and the scene editor without changing the curve's shape. Make sure that you aren't also scaling the x,y,z scale keys of the item when you scale the timing. (I usually go into the graph editor and delete all the scale and rotate keys except for the keys on frame one leaving only the x,y,z translation keys for editing)

I just created a simple rocket ship vehicle in modeler with it's nose pointing in the +Z axis. I next made a spiral of points and created an open curve in layer 2 so that I could make sure the scale of the path I saved out as a motion path was the appropriate size for the rocket. After tweaking the path to a shape that looks correct for a space vehicle I exported it out as a path to motion file. After loading and selecting the rocket object in layout I loaded the motion file and then under the contollers and limits tab of the motion panel (key "m"), I set the heading and pitch controllers to "Align to Path". The rocket now follows the motion path as desired.

Not as easy a having a spline curve with bezier handles to grab and edit within layout but it's pretty easy and the timing is scaleable without affecting the original curve's shape.

03 March 2002, 03:11 PM
I think Chewey has this thing pretty well figg'red out. I just have a quick question that'll probably take things to the next level: How about distorting and object along a path... like a snake?

Now, last time I was fooling around with the "Serpent" displacement plugin I couldn't get very satisfactory results. LazypointsMP and Inertia-based tests didn't get very far either, so, anybody have any ideas?

03 March 2002, 05:27 PM
Actually, Chewy's reply while gave some good overall pointers failed to meet my original request. How can one control the motion in this manner, and stop it and reverse it, speed it up ETC.

Editing and scaling the motion in the graph editor does not do this. What I eneded up doing was to create the motion path as desired and attached a MOCO_NULL to it via the curve constaint, and checked align to path. Then I created a new CAM_NULL and CONTRL_NULL. Parented the object Then I referenced the motion from the MOCO_NULL into the CAM_NULL via several expressions on the x,y,z,h,p,b.

MOCO_NULL .pos(CAM_NULL .pos(Time).x).x
MOCO_NULL .pos(CAM_NULL .pos(Time).x).y
MOCO_NULL .pos(CAM_NULL .pos(Time).x).z

MOCO_NULL .rot(CAM_NULL .pos(Time).x).h
MOCO_NULL .rot(CAM_NULL .pos(Time).x).p
MOCO_NULL .rot(CAM_NULL .pos(Time).x).b

The referenced motion in MOCO sent into the CAM_NULL (which has my camera parented to it) and gets controlled by the CNTRL_NULL on its x axis.

Now when I drag and keyframe the CNTRL_NULL it will cause the camera to spped up, slow down, stop, and reverse all while attached to the original curve.

Now, if only I could figure a way to interactivly reshape that spline path.

03 March 2002, 08:01 PM
I hate to beat a dead horse but I'm able to stop and reverse using the graph editor in 7b although that method you came up with sounds like a cool one. There are also a number of lscript path tools on that might be worth checking out.

03 March 2002, 01:13 AM
i thought that in lw, when you animated something moving or whatever, it made a spline, can't you just edit the spline it left behind to what curve and shape you need?


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