[Bf-funboard] ] constraints

Ton Roosendaal bf-funboard@blender.org
Tue, 8 Jul 2003 16:39:59 +0200


Hrms, then the confusement is in literally translating Constraints, as  
something that is 'limiting' or so...
For me a 'Constraint' is a more a general description of a relationship  
in Blender. These relations 'constrain' certain aspacts of one object  
to another. The fact that you can still select and move a Child Object,  
doesn't mean it is not 'constrained'. Do a SHIFT+CTRL+P to find out  
what Parenting really is...

For a user, to present this new system, we can simply keep the old  
commands in Blender: CTRL+P, ALT+P, CTRL+T, ALT+T. Even the menu that  
pops up can keep the old name. So nothing changes... until a user wants  
to tweak the parent or tracking relationship further.

We can also rename "Constraint" to "Relationship" or so... I think the  
first name is just more common used in other 3d programs.


On Tuesday, Jul 8, 2003, at 14:16 Europe/Amsterdam, Jean Montambeault  

> Ton Roosendaal wrote:
>> Hi,
>> Sorry, but I miss the point as well Jean...
>> Please elaborate the statements below:
>>> split up it's kind of constraints
>>> (which are and utterly different animal than what we call  
>>> constraints  in Blender for now, I hope that we can agree on that at  
>>> least)
> The way parenting 'constraints' its children let us free to transform  
> the children at will.
> The way our present constraints operates, if you 'Copy location' the  
> constrained object can't be moved independantly.
> From the user's point of view the difference is absolute although it  
> could not be so from the programmer's point of view.
> Something else that probably has no meaning from the programmer's  
> point of view but makes a lot of sense from the user's :
> when defining a mini-coordinate system, I fine tune my animation and,  
> once satisfied, give to every element a parent, usually an empty.
> From the programmers standpoint this is just constraining as usual.  
> From my user's point I have no use for the concept of constraint at  
> all ; it wouldn't be fertile. What I'd rather see is a bunch of  
> children *using* the parent to extract coordinates from it. Other than  
> that the parent has no influence and could be in China for what I > care.
> If you accept that conceptualisation you get an unexpected extention  
> of the tool that can proove very rich.
> I understand that this is not what the algorithm says but it has no  
> importance. The use extends the tool : always.
> I am sure that if we go Matt's way and invent all kinds of  
> constraints, even when some may seem to be of limited usefullness at  
> first, you never know what side effect might develop, you never know  
> what the creativity of the user will extract out of them. The  
> perspective really fills me with enthousiasm.
>> and:
>>> But entirely getting rid of a simple, efficient , universally   
>>> understood and used tool won't ever make the smallest bit of sense  
>>> to  me.
> Then again this must be seen from the user's point of vue, who, sorry  
> to say, doesn't care for the underlying algorithms.
> The user's may come from another software and chances are that he is  
> familiar with parenting since it is of an almost universal use : why  
> make his life difficult when leaving a minimal parenting system to  
> greet him would make the transition so much easier : universality and  
> efficiency since it facilitates the communication.
> ( Not to worry : with a powerful constraining system as discussed here  
> nobody will want to live without it.)
> 'Make parent' is also a quite simple way to access to an often used  
> set of constraints : simplicity and efficiency.
> Give the poor soul that much no matter how it is achieved : use your  
> new constraint system at will but make it transparent on that occasion  
> for the user.
> Hope this is clearer.
> Regards.
> Jean
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Ton Roosendaal  Blender Foundation ton@blender.org