Animation "jumpy" using camera path

[tedg]

Help!!!!
I apologize in advance for the long explanation.....

I'm trying to do a "walk thru" animation using Viz Render 2006 in a 3D model.
I've done a couple of "walk-around and through" animations on this before and it seemed to be ok. The problem was the animations were too short and didn't focus on the specific area of interest.

I'm using a 2d "spline" as a camera path and am adjusting the head turning and tilt angles as well as field of view as I animate. This seems to be a NEW problem since I lengthened the animation time to 500 frames and made it a much shorter polyline (spline) for a path. The result is the animation runs along the path and the camera jumps side to side as if it hits a sharp bend on the path, like a train on a bad track! I didn't have this problem before, maybe I just got lucky? It's as if the camera is hitting a vertex on the polyline and changing direction.

Also, I tried using a target path along with the camera path and that helped, but I couldn't control where I was looking: left, right, up down, just straight at the path.

Anybody out there have any advice on this?

Thanks,
Ted

[Steve_Bennett]

You may need to adjust the vertex corners to be bezier's. Having a simple vertex IS a sharp corner. You mentioned you are using VIZ Render? I didn't think it was possible to create polylines in VIZ Render. I know you can create them in Autodesk VIZ though. Let me know which it is and I can give you some more tips on where/how to set the corners as bezier.

[tedg]

I created the "spline" in the autocad model and selected it as my path in Viz Render.

Does that help?

Ted

[.chad]

did you change the spline and number of frames after you set it all up initially? Viz / Max can react oddly if you make changes to the number of frames without remapping the camera position throughout the frames. if you make the changes after the intial camera path is set, it will still be trying to fit the intial path timing into the new path, which from what i remember can result in choppy and acceleratored movement.

[Steve_Bennett]

I created the "spline" in the autocad model and selected it as my path in Viz Render.

Does that help?

Ted

Ah, that makes more sense. In that case, someone familiar with Splines in AutoCAD would need to chime in. It might be the cause of the jumpy path, hard to say. VIZR is so limited it drives me crazy to try and work with it. You might be better off using a free camera - however I don't know if that would work since there does not seem to be a key frame button and not to mention there is no track view either.... arrrggghhh!!!! I'm getting claustrophobic!!!!

I guess what I'm saying is that VIZR is not the best suited for live animations. Full VIZ or MAX are the way to go if you are trying to do that.

[tedg]

did you change the spline and number of frames after you set it all up initially? Viz / Max can react oddly if you make changes to the number of frames without remapping the camera position throughout the frames. if you make the changes after the intial camera path is set, it will still be trying to fit the intial path timing into the new path, which from what i remember can result in choppy and acceleratored movement.

What I did was changed to the 500 frames, and then created my camera and selected my path. I had tried doing it the other way but my camera would stop moving at the previous frame number. Like if I had 200 frames and the camera path set with that, and increased to the 500 frames, the camera stops moving at the 200 frame point on the path.

I'm wondering why this is happening now? Is it possible the combination of incrased frames and shortend path causes this?

[tedg]

This is just an update...passing along info to anyone having the same problem

I wasn't able to find out why my camera was "jumpy" on my assigned spline path.
However, what I did to get my desired animation was to use the "free camera" and just move it around while manipulating the head turning and tilting as well as assigning the correct "z" value when I wanted to change elevation. It seemed to make it animate smoother because it wasn't riding along a path.

I would like to know why it was doing that if anyone knows.

Thanks

Ted

[dellis]

I use MAX but this sounds like a very similar problem that i dealt with many years ago. Heres the situation:

When animating along a spline path, one of two situations arises:

-you keyframe where you want the object to be along the path as percentage keys
-vertex amount and spacing dictates the motion over the total frame duration.

Its not really easy to understand in the interface whats going on so i'll explain how it works under the hood.

By default MAX uses the number of vertices and there spacing along the spline to animate the speed along the path over the amount of frames specified. ( I can explain this further if anyone needs it). Essentially if you want constant velocity you need exactly the same number of vertices in your spline as you have total frames of travel....with a constant distance between vertices. (an easy way to get this is to normilize the spline).

Now if you want to go the keyframe route, which is most preferable, you have to turn on the constant velocity checkbox in the motion panel for the object on the spline path. This doesn't make any sense but this must be done in order for MAX to use the keyframes to determine its position along the spline. Once you do this you can set keyframes for the percent and frame for the object. This allows you to draw the spline path however you want and all the information is in the keyframes.

Not sure if this is what the problem is but it sure sounds like it. If anyone needs a deeper explanation or a sample file let me know.


Dwayne D. Ellis
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[tedg]

Thanks Dwayne.
When I get back into another animation I'll check it out.
I'm not an expert at Viz Render but it sounds like your advice may work.

I ended up just doing a free camera and moving it along manually to do my animation.
It worked pretty well but I'd like to learn more about manipulating the key frames.

Thanks again for the info.

[dellis]

No problem. Learning to keyframe is extremely useful!!!


Dwayne D. Ellis
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