I have come across what appears to be a weird bug, or possibly a calculation error, or something similar. I have found a work-around, but wanted to explain what I discovered what I found to be the problem, and my work-around. Not sure if it is something that needs to be fixed, or simply a limitation in the software.
I have a model with several tall objects that range from +1000' to -300'. The horizontal dimensions are not as large (500' x 500'). I am animating slender shafts that extend up/down in various ways. To animate these, I create a 1" tall cube, then scale it up to 300' tall. When I did this for a cube starting near the ground level, extending 300' down, it works fine.
When I create a similar 1" tall cube that starts at -300' and scale it up so it is 300' tall, it causes a problem. First, I noticed that once I did this, SketchUp starting clipping the camera view (causing walls to get sliced open, not showing faces, etc; similar to when you zoom it too close on a really large object and the perspective gets forced/broken). One other characteristic I noticed (I have both ground and sky planes enabled): As soon as the object starts scaling, the relationship between the ground and sky planes changes (the ground starts extending in the distance, as if the overall model is getting larger).
Disabling the scale-movement fixes the problem (after saving, exiting to SU and then back into Animator).
It seems that when I scale the object that starts at -300' that the resulting object has erroneous "super duper tall" data or something that makes SU think it is taller than it actually is (or that the model is much larger than it actually is).
I tried many things:
- Scaling the object a little, then a second scale for the rest of the way
- Using taller objects to start (partially helped, but just reduced the problem to be not noticeable - but it still existed)
- Constructing a full-height object and scaling it down myself, to have Animator scale it back up
Finally, when I moved the offending object up to the ground level, and let it extend 300' above the ground as a test, the problem disappeared. I discovered that if I "save" the 1" tall cube above ground to start the animation, it can remain hidden by layer. Once the animation begins, with the object hidden, I move it down into position, and then have it appear when needed and it is able to scale up as planned.
It seems that the object's original position when saved into Positioner is part of what causes/resolves this problem. The deeper below ground the object begins, and the more you need to scale, the more severe the problem. Note that I want these cubes to "appear" from nothing and grow very tall, so I am going from 1" to 300' which is a LARGE scale factor.
It may be that a large negative number in the original coordinates of the object causes some math rounding or calculation error? Anyway, I wanted to pass along my troubleshooting in case it is something that you can fix.