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Caught on video--C4D Rotate Tool is Whack

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Jason BurnettCaught on video--C4D Rotate Tool is Whack
by on Feb 24, 2013 at 8:25:04 pm

I am trying to do a simple animated arrow. It has very explicit start and end positions, so the goal here is to achieve this particular effect.

I create the arrow using linear beziers, 3 of them. Because I didn't like the way the filet caps were working, I created a bottom arrow, a middle arrow and a bevel arrow (slightly smaller). I made sure that my lines were subdivided by 1 unit to ensure smoothness. I created my loft nurb for the arrow shape and set to linear interpolation to ensure crisp edges. I set the subdivisions to 300 along the length and my arrow looks perfect... almost.

So I grab the lasso tool (made sure not to have the "select only visible" option chosen)and selected all of the endpoints (6 points total 2 per arrow) and selected Mesh->set point value with Y:center selected. Now my nurb is perfect--just the way I wanted it.

So, in order to make this logo, I grab an arc spline with 180 degree rotation along the zy axis (perpendicular to the arrow, running along it's length). I spline wrap my arrow nurb around the arc and set the "banking" setting to 90 and click "keep length".

I use the arc tool instead of the circle tool because I don't want the entire arrow to be wrapped. I want the head to remain unrounded when I spline wrap it.

I take my bent arrow group and my arc spline and duplicate them.

Then I set about the tedious task of getting them to line up for the camera just exactly the way I want.

The lower arm of both arrow heads have to be parallel. Then have to appear to be at 90 degree to each other, but in reality, they are not. I finally get them setup perfectly and now I am ready to rotate them.

Enter video:

C4D Whacky Rotation

I select the arc for the first arrow. At frame 0 create an anchor point including just the rotation values (though I have tried it with all the values, same problem).

I move to frame 45, grab my Rotate tool, with the Arc path selected, I rotate while constraining the rotation to the red axis. Voila! It looks terrific. I make a keyframe, feeling good about my animation.

I move to frame 0, press play and C4D decides they know a shortcut to get from where I started to where I ended. They completely ignore HOW I got there, and their plan simply doesn't work. This, by all rights, is a bug. I am sure there's a reason why they have chosen this terrible behavior, but it is just that: terrible.

Any suggestions on how to compensate for this poor behavior?

Thanks for any help.


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Adam TrachtenbergRe: Caught on video--C4D Rotate Tool is Whack
by on Feb 25, 2013 at 6:39:51 pm

This is a consequence of the HPB rotation system, which is unintuitive but apparently used for good reason. For more on that search for HPB in the help file.

To actually fix the problem (!) ... delete all your rotation keys and then do one of two things:

1. In your objects' coordinates tab, freeze transformations before keyframing the rotation. That will set the local coordinates to zero even though the objects are rotated in world space;

2. Change the rotation order so that your rotation axis is the first axis. In your case, since you are rotating on X, you would, e.g., set the rotation order to XYZ.


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