Baffling problem that is a follow up to unresolved problem (Object created by joining several objects doesn't rotate uniformly consistently). This object is created by joining 3 objects..large gear, shaft and small gear. Its rotation is constrained to object in scene that's hidden along with other objects. When I play scene it rotates correctly until I change direction of target object, Then the large gear appears to stop rotating while its origin (denoted by axis and widget) and the shaft and small gear resume rotating. Here's youtube vid https://www.youtube.com/watch?v=NfXAFHCkRxE&feature=youtu.be

My Blend:

Any ideas?

  • $\begingroup$ To get better answers please upload the file. Please use blend-exchange.giantcowfilms.com and edit the resulting link as part of the question. $\endgroup$
    – user1853
    Jun 8 '16 at 16:38
  • $\begingroup$ Its too big--560mb-- and contains proprietary designs i'd rather not release. Lemmee see if i can duplicate problem in a smaller file $\endgroup$
    – dino808
    Jun 8 '16 at 18:54
  • $\begingroup$ Here's a smaller file with section of problem scene <img src="http://blend-exchange.giantcowfilms.com/embedImage.png?bid=1433" /> $\endgroup$
    – dino808
    Jun 8 '16 at 19:55
  • $\begingroup$ If you rotate something at the right speed it will appear to be stationary even though it is moving. Try moving the key frame a little. $\endgroup$
    – Xtremity
    Jun 8 '16 at 21:48
  • $\begingroup$ Object is keyframed to rotate at same constant pace in both directions..it is NOT moving $\endgroup$
    – dino808
    Jun 8 '16 at 22:12

As already said by @Xtremity in the comments, it is rotating but you don't notice it. Your big gear has 30 teeths, so every 12 degrees (360 / 30) one teeth. Before the short stop, you rotate by +6 degrees every frame, so half a teeth of the big wheel. After the pause however, you rotate by 12 degrees, exactly one teeth, per frame, so you just don't see it rotating.

By the way, you're not rotating in the opposite direction after the stop, it just looks like it.

Rotation in frame 209:

Frame 209

Rotation in frames 210 to 230:

Frame 210-230

Rotation in frame 231:

Frame 231

You can clearly see, that before frame 210 it rotates by 6 degrees, after frame 230 by 12 degrees.

  • $\begingroup$ Really? So why is the rotation of the larger gear in either direction noticeable when rotated frame by frame from 190-210 and clearly not from 230-250? $\endgroup$
    – dino808
    Jun 9 '16 at 2:38
  • $\begingroup$ Because from 190-210 it only rotates half a teeth per frame, from 230-250 a full teeth per frame. You can't see the difference since all teeth look exactly the same, so you don't notice, that after one frame, every teeth rotated to the exact position of the next teeth. $\endgroup$
    – tkausl
    Jun 9 '16 at 14:52
  • $\begingroup$ Just go in edit-mode, grab one teeth and move it outwards a bit, then play the animation again, you'll see it's actually rotating. $\endgroup$
    – tkausl
    Jun 9 '16 at 14:53
  • $\begingroup$ (sigh) that doesn't help...i need it to LOOK like it's moving during frames 230-250, just like in frames 190-210..is there any reason why it would not look like it's moving when the rotation rate is the same. $\endgroup$
    – dino808
    Jun 9 '16 at 19:36
  • $\begingroup$ Because the rotation rate is not the same! $\endgroup$
    – tkausl
    Jun 9 '16 at 19:37

Per tkausl answer, I revised scene to rotate object at same rate by changing keyframe to rotate 6d/frame in opposite direction so rotation is visible. Also duplicated problem..gear meshes appear almost static when tooth count=frame count producing rotation of one tooth per frame..I'll avoid this now on.


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