I definitely needed to see this one to work out what was going on. I can tell you the general rule of how to fix it, but you’ll have to fix it in several different places.
The basic problem is that in the builder, things that are set to update every frame don’t start updating until the first frame. In order to update the position and orientation of the clock hand before the first frame (so it starts in the correct position and doesn’t jitter), you need to manually set its position and orientation in the “begin routine” section of the code component on that trial. This is not all that intuitive, so I’ll add some illustration of what I’ve done to get the FirstEvent routine working.
First, let’s look at the properties of hand_6 in the builder, which were mostly correct except that you should remove the dollar sign before firstAngle, as I have done here:
Now, in the code component, I’ll give you an image of where this code goes and separately the text of the code itself:
hand_6.setPos([(0.095 * Math.cos(((3.14159 / 180) * (firstAngle - (t * 140.625))))), (0.095 * Math.sin(((3.14159 / 180) * (firstAngle - (t * 140.625)))))]);
hand_6.setOri((firstAngle - (t * 140.625)));
The console.log statement was just there to help me ensure the issue wasn’t with how firstAngle was being set, that turns out to be fine.
This probably looks rather familiar as it is the same calculations you put in the builder component with one important change (see below), but now we are running those calculations for t=0 before the first frame is drawn, and so the hand should appear in the correct orientation.
Note that you’ll need to change the position calculation to use Math.cos and Math.sin instead of just “sin” and “cos” when you do this.
I ran into a separate issues with the slider not rendering that you may need to do something about, but to start with you should try doing this to get rid of the flicker. The same general principle should apply to everything: If you need to set the orientation and position of an object before it is drawn, you should do it in a code component in the “Begin routine” tab as well as having it update each frame in the builder component. You could also set it to constant in the builder have the same lines in the “each frame” of your code component as well, but that’s effectively what setting it to “every frame” in the builder does anyways.
I hope that helps!