Object movement when using constraints - I just don't get it

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Object movement when using constraints - I just don't get it

Post by Schmed » Tue Sep 10, 2013 12:15 am

So I've been using Blender for months now (I've previously used 3DS for years). In every tutorial and book that I've read, there are instances where I'll have to add a constraint (either modeling or posing) and as soon as I do that, the target object inexplicably moves or rotates to some arbitrary position. Then, I have to fiddle with axes, apply rotation and scaling and STILL, the object will not move back to where IIIII, the modeler, want it to go. Utterly ridiculous and things like this, in my opinion, are what keep this application from becoming professionally accepted.

Yes I have applied scaling and rotation. Yes I have tried every axis in the "to" and "lock" boxes. Yes the origin is where it needs to be. Yes, there are no cyclical parents or children. Still, a lot of the time, the object won't move to where I want it... unless of course I remove the constraint.

It seems pretty simple: "Hmmm. Copy rotation. That means if I spin this object, that object will "copy the rotation." Yes! That's what I want. I just want object B to rotate the same as object A. "Copy Rotation". So why for the love of a meatball would object B move or change it's rotation after I add a constraint?"

I'd love to enter a bug report, but I'm sure it'll be closed because it "can't be duplicated" or "it's by design" or some other nonsense.

FACT: IT DOESN'T WORK. FIX IT. If only it were that simple.

There is absolutely no rhyme or reason why an object should move or rotate when assigning a constraint. I spent hours and hours moving the origins of a hundred objects to get them precisely where I want them. Then, I add a constraint and BOOM, I have to spend hours more to get the object back to where I want it. And a lot of the time, I simply can't.

Utterly ridiculous.

Whats worse is every book I've read just tells you to fiddle with the axes until it works. What they don't tell you is what to do if no amount of fiddling works. So seemingly, no one knows why this happens, they just accept it.

And that's one reason why Blender will never be accepted professionally.

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Post by stiv » Tue Sep 10, 2013 1:05 am

If I read this right, you are upset that adding a constraint to, for example, keep a certain axis pointed at another object makes your object move or rotate. Is that correct?

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