Problem with bones in armature streching when rotated.

Hello. This is my first post here. I’m having some trouble using blender. I was making a 3D character and added an armature to it. But when I rotate it’s arm the bones of the armature are stretching. Is this a glitch/bug or am I doing something wrong. Is there a setting I am supposed to change to avoid this from happening?

When I rotate it’s arm 90 degrees down it doubles its size for some reason:

So I thought maybe I’m doing something wrong. So I opened up blender again with the default cube and added an armature. I put the armature next to the cube to compare the size. And I rotate the bone 90 degrees down. The bone seems to have doubled in size.
Before rotating bone (for illustration purposes);

After rotating the bone that was on top (notice how it has doubled in size):

Is there something I am doing wrong. Missing to click some button or change some setting?

Thank you.

(I’m using Windows 7 64 bit (if that helps in something) )

(Apperently they won’t let me post pictures for being a new member to this forum so I can only add the comparison pictures with the cube test)

Welcome to BA!

I’m thinking (in the case of the pics posted) that you scaled the armature in object mode on the z-axis, can’t tell for sure since you have ‘stick’ display on. To check this - in object mode, select the armature and look at the top of the transforms panel (n-key in the 3d view). The scale should be 1, 1, 1. If the scale is say 1, 1, 2, then that’s the problem. The scale needs to be the same in x, y, z, if one or two of those is different, then it causes problems like you’re displaying.

More than likely, what you did was once you added the armature, while still in object mode, you scaled it on one axis. Normally, what you should do is after adding the armature, enter edit mode, then move the bone around as needed. This way you won’t change the scale of the object. To correct the problem - in object mode with the armature selected, do a ctrl-a -> apply scale - to reset the scale to be 1, 1, 1. Likewise, the scale of the object you’re rigging should also be 1, 1, 1. Check and correct that just like you did for the armature.

Another rule of rigging is that your object & armature should have the same point of origin. To check this, select the object in object mode, you’ll see an orange dot indicating it’s origin. Then select the armature in object mode, again it will have an orange dot. If they do not match - select the armature in object mode, shift-s -> snap cursor to selected, then select the object in object mode and in the tool panel (t-key in 3d view) at the top, click on ‘origin’ and choose origin to 3d cursor.

Hope this helps,
Randy

Thank you very much!!! Your post was very helpful. I corrected the problem.