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**Here is my blend file.

I am making cement mixer so I want this object (mixer drum) to just rotate but not come out of its base.

enter image description here

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  • $\begingroup$ Your local y axis is skewed, this will show in edit mode. You want the local y axis pointing directly out of the mixer. Like this The easiest solution is to add an empty to scene as bowl parent and rotate that. Will look for links as I've seen this one many times before.. $\endgroup$
    – batFINGER
    Oct 21 '17 at 14:12
  • $\begingroup$ I am a beginner and this makes me so much confused, lol I did not know it could be very difficult. $\endgroup$
    – Aamir
    Oct 21 '17 at 15:06
  • $\begingroup$ Adding an empty did not help. $\endgroup$
    – Aamir
    Oct 21 '17 at 15:08
  • $\begingroup$ I tried to apply the "empty" method to your file, to create an answer, but unfortunately it appears that the rotating part is not modeled well... due to this, even correcting the local Y axis it will make rotation around it irregular (the mesh will rotate around corrected local Y axis in elliptic way, so to say)... this make it more difficult to solve... It will take more time and much many more solution steps, if possible at all. $\endgroup$
    – m.ardito
    Oct 21 '17 at 15:34
  • $\begingroup$ Can you model another same (drum) model as it should work and try again?,,,,,,,,,,, i am really sick of it. $\endgroup$
    – Aamir
    Oct 21 '17 at 15:42
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I'll try to show here what I said above in comments.

This is the drum from your object and I highlighted its pivot point as it is in the file. I also placed an empty to its current position, as a marker.

enter image description here

But if you think that the pivot point is well positioned, you should try to "recalculate" it origin to the geometry

enter image description here

And you get this: you see it is now a different position... this is what makes the drum to rotate wrongly even after correcting the local axis...

enter image description here

If this mesh was designed better, this following method would have worked, to reset the local Y axis to get a better rotation animation:

first, I selected a ring from the mesh (which is supposed to rotate well around a corrected Y axis), duplicated it as a separate object, and used it to calculate the current rotation using an empty:

enter image description here

the empty is placed at the new ring center (obtained with "origin to the geometry") and in side view, with the help of vertex snap tools, rotated until it matches the ring mesh, and you so you get the (wrong) rotation angle between the empty and the ring.

enter image description here

you then have to use that angle to correct the real "drum" angle

enter image description here

as you see the drum Y local axis has now the right rotation, but if you compare the empty position and the drum pivot, it is easy to understand that this will not work good in animation either...

I cannot model the drum for you (btw I'm on holiday) but at least you know something more than before :D maybe someone else will add more help...

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  • $\begingroup$ Thank you so much for very clear answer, i really appreciate $\endgroup$
    – Aamir
    Oct 22 '17 at 18:51
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Re-align the local axis.

  1. Object mode.
  2. Select the mesh object and transform its origin to center of mass (volume). Object > Transform > to Center of mass (volume).
  3. Clear the keyframes.

  4. Put view in right ortho Numpad 5 I've also changed to wireframe view Z and rotated the mesh in x (quickly by eye) to align vertically. (See note at bottom). So don't go by the 14.3 in iamge, take care in this step to get best result.

    enter image description here

  5. Apply rotation to the object. This will realign the local coordinates. Object > Apply > Rotation ctrlA

  6. Change the euler rotation order to ZYX Euler The x tilt wont effect the Y rotation in this order.
  7. Rotate back to match the tilt, Now can keyframe in Y to make the mixer spin enter image description here

Ideally would rotate in step 4 to align horizontally. Maxing the axis of rotation z after applying rotation. This would take out the need for step 6

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Without having the blend file to look at, it looks like you need to change the object’s origin point. It could also be that you should rotate around local axis rather than global.

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  • $\begingroup$ I have attached my blend file please have a look. $\endgroup$
    – Aamir
    Oct 21 '17 at 8:58
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    $\begingroup$ this looks more like a comment that an answer... now that the file is available, you could improve this answer... $\endgroup$
    – m.ardito
    Oct 21 '17 at 14:34
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Rotate about local axis instead of global. enter image description here

You will find it in transform orientation.

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