View Full Version : camera/path tutorial

08-19-2006, 11:22 AM
I'm trying to get my camera to follow a path along a roadway, but my methods fail enfuriatingly. maximum tedium, minimum success..

I've made paths a variety of ways (bezier, points) and the camera motion always ends up jerking this way and that, has wobbles, slight backtracks, all stuff I don't see when I'm setting up, but of course which are there when the rendering is done 45 hours later!

Any good links to help me see what I'm doing wrong and learn how to do it right?

thank yoU!


08-19-2006, 02:42 PM
I guess you get a lot of keyframes...i am sure there was smooth option in dopesheet..but cant find it now....so try this:

Open dopesheet...(click on the top edge of the time line)
Keep just few important keys.. and delete the rest (click drag to select)
then adjust the camera position manualy if needed.

08-19-2006, 03:52 PM
I have never seen this so I'll go out on a limb and take some guesses.

Are you using a renderFarm and a Follower?
Maybe something is wrong on one of the render nodes and the Follower.

Is your scale wacked - i.e. are you using a microscopic scale or a huge huge scale. I've heard that rounding errors can creep in and that might be causing your problem.

45 hours! OK what is taking so long? Are you rendering 32767 frames?
Strip the scene down to bare minimals and render in a reasonable time.
Try stand alone and then the renderFarm (if you are using one).

If the problem goes away, it may not be the camera at all.
Are you creating the landscape with procedurals. Maybe it only looks like the camera motion is the problem. Maybe it's in your procedurals.

Are you using one of the new LW cameras?
Maybe you actually have discovered a new camera bug.

If none of this helps, call Lightwave Support.
I gotta believe that if this was a common problem the entire community would be screaming. Then again, maybe something specific to the Mac is the issue.

Also post something at SpinQuad (http://www.spinquad.com/forums/index.php?). Lots of brilliant people over there.
I'm not one of them.... :D

PS these types of problems are exceedingly tough to diagnose from afar. I'm only making these suggestions so you might hear something more from the community and try a couple things.

Good luck. :thumbsup:

08-19-2006, 04:27 PM
I might need to look at the scale issue.

the rendering takes so long bcs it's spread out over about 480 frames...average of 4 mins/frame; some quicker, some longer..adds up over the sequence.

I think what my issue is is 2 things: lack of control setting up the camera/path and null the cam is supposed to be looking at, and many keyframes, some of which get moved somehow and cause these wierd jogs in the camera's motion, but which I somehow don't see when in layout, looking at camera view, and using the keyboard to advance 1 frame at a time..looks ok then, but not after rendering's done.


08-19-2006, 04:33 PM
remember you can always run an opengl preview to see how things look before you render

one tip I would give would be to set your start and end keyframe before you add any others this means your camera would move at a constant velocity along the whole path and when you are setting mid keyframes you get an idea of whether you are slowing or speeding up your camera motion

08-19-2006, 04:52 PM
If you use feild rendering... big diffrences between 2 key frames that are close to eachother will look something like you described.

08-20-2006, 01:18 AM
You didn't mention if you are using a renderFarm or a motion Follower.

You are going to have to methodically debug this problem.

Strip the scene down to the bare minimum.
If you are using blur - take it off.
Take off anti aliasing. Take off surfacing if you need to.
Better yet, remove all objects (except the null) and lay in a totally flat ground plane and surface with a grid - keeping all the camera keyframes.

Render only a small range of frames where you know the problem exists.
Render it out to a sequence and find an exact frame where the problem exists.
Take a look at your postion and especially Rotation around that frame.
I'm wondering of the Rotation is taking a wild path to a certain heading or something.

If you post a scene with no objects but the camera, light and null and all keyFrames for the 480 frames we could take a look at it. I'd pretty much follow my own suggestions and lay in a grid ground plane and find the offending areas. I am also starting to suspect that the camera movement combine with the null you are pointing at is causing the problem. Wierd that you are saying that some keyframes get mysteriously moved. Never saw that.

Any motion plugins/LScripts you are using?

Back in your court. 8/

08-20-2006, 09:43 AM
You didn't mention if you are using a renderFarm or a motion Follower.

Wierd that you are saying that some keyframes get mysteriously moved. Never saw that.

Any motion plugins/LScripts you are using?

Back in your court. 8/

thanks for the ideas...I just have 2 macs I'm using to render these clips. not using any motion plugs or LScripts.

as for keys that get mysteriously moved, I should clarify..I move the cam to position, make a key, move again, make a key. now, sometimes I go back and adjust a position that I've already keyed, but I always do that 1 dimension at a time, ie, y OR x OR z.

this seems to be introducing little "kinks," but it seems a drag I only get 1 crack to get it right..going back and adjusting already-made keys could be introducing the problem, tho I feel I"m VERY careful when I do adjust.


08-20-2006, 12:29 PM
When I had quite a few keyframes to optimise, editing them in the "graph editor" always worked for me. It is also a great way to get rid of unnecessary keys.

08-24-2006, 12:11 PM
Hey..I am sorry for not getting back MUCH sooner to thank you all for your replies and suggestions...

while trying to figure out the cam path thing, I decided to develop another aspect of that scene, then revisit the path issue later, so I'll be trying these suggestions soon.

thanks again!


08-25-2006, 09:28 AM
set a null as the target of a camera and then move that along a path?