Empty with Follow Path Constraint produces sheared items

Empty with Follow Path Constraint produces sheared items
I do not want sheared items.
The empty parent is displayed as a sphere in the correct case.
When I add the Follow path constraint the empty parent sphere display become sheared and squashed with certain rotations in the incorrect case.
X seems to be correct.
Y and Z are incorrectly sheared.
This sheared empty parent produces a shear in the child items.
Blender 2.55
Thanks for any comments and solutions.

you may have scaled the curve in object mode… reset the path with alt+s to find out

There is also a checkbox on the constrained objects constraints tab called “curve radius”. The description of which is “Objects scale by the curve radius”. Sounds like this could be the case if you have x as the constraint axis.

On another side I find that using the curve modifier to follow a path has some easier applications Especially in that you don’t have to set pathlength in frames etc… I posted an example here. http://blenderartists.org/forum/showthread.php?t=203473

I probably scaled the curve both ways.
I never hesitated in past to do this.
I followed your suggestion which gave me successful results! ( at this late hour)
I will perform full test in 8 hours.
Please provide a link or an explanation if you have one.
or documentation that tell me not to scale path curve in object mode

if you parent an object -your empty and spheres- it will inherit object level transformations, like location, rotation and scale…! that’s one of the points of parenting
anyway if using a follow path constraint, parenting isn’t really that necessary :wink:

edit: and if you need to, you can apply a transformation to an object with ctr+a before parenting anything to it

liero First of all Thank You. That problem cost me only 1 day. It could have been worse. … Regarding your last message. My question to you is How did you know the following? ----------- Follow Path Constraint has expected behavior when the path object scale is uniform. Example (1,1,1). Follow Path Constraint has unexpected shear behaviour when the object scale is nonuniform. Example (1,2,1) Apply the scale transformation with Alt-S and make the path scale uniform for good results. ----------- Was this word of mouth? A web page link? A FAQ. A blender.org document. The path is NOT a parent as I understand. Is this shearing behavior a defect? I am always trying to find good documentation for Blender. Sometimes tracking down the documentation for problem leads to a better understanding for me.

well it just makes sense, the point is that you parented your empty, it has nothing to do with the path constraint… so if you scale the path the child object will follow the transformation, and it is the expected result… regarding documentation I still find the old 2.49 manual very usefull, so it is this forum… have a nice day!

Constraint versus Parent.
The following message is filled with perhaps because I am striving to learn express myself in Blender jargon.
Blender 2.55
Perhaps I do not understand the formal definition or blender lingo of <<parent>>.
Perhaps <parent> has many related imprecise uses.
Users may be explaining one way and documentation writers another way.
I get that Control P makes a parent which is graphically identified in the Outliner window.
In the <object> master panel there is a panel named <relations> which has an entry named <Parent>.
The path constraint is not identified graphically in the Outliner window in the same fashion.
I do see a relationship line … differently colored than the other Parent… faintly in the 3D windows between the path and item.

Various documentation has differently levels of accuracy and current worthiness.
This is the link I found for parenting.

does not seem to state the constraint is a parent

Constraints are object features, i.e. they control in various fashions the objects’ transform properties (position, rotation and scale).

My questions
Perhaps the writing style is to mix the concept of
Constraints with Parent rather casually.
Perhaps it is more common to say
Delta parents the child Bravo
than to say
Delta constrains the transform properties of Bravo
Perhaps Constraint is the new and improved and generalized <<old parent concept>> sequence.
I may pose a new question about
Constraints vs. Parent
in another thread.

Liero Thanks.