[Sidefx-houdini-list] Buggy Objectt CHOP with bearing option

Pablo Giménez pablogipi at gmail.com
Mon Jul 5 08:14:34 EDT 2010

Looking more closer to the objlookat() function it seems it is doing the
same calculations as the lookt at parameter in the object properties.
I mean, it always orient the Z local axis of the object towards the target
object. The up vector actually only rotates the object arounf the oriented Z
In Maya aim constraint you have an aim Vector which is really useful.
So the thing I am looking for is to be able to orient any axis, X, Y or Z,
so one possible solution is to apply a secundary rotation if I need the Y or
X axis rather than Z.
I have made some test multiplying the output of objlookat by
rotaxis(90,"[0,1,0]) to use the X axis as the aim vector, but not working
really well so far, I will keep trying.

El 2 de julio de 2010 18:47, Pablo Giménez <pablogipi at gmail.com> escribió:

> Thanks guys for your answers.
> Yep looking at the dependency dialog it shows some infinite loop problems,
> this makes me thing that it is impossible to make an object CHOP work in
> bearing mode calculating the reference of one objec to to another and then
> exporting the result to the reference value. I understand becaouse of the
> nature of CHOPs this is going to happen, but specially in the object chop is
> very handy to export values to the reference object, so I think it would be
> a very handy RFE to make the object CHOP avoid this infinite loop in any
> way.
> Finally I have choose to use the objlookat expression in a Channel CHOP. I
> need to implement it in chops to keep consistency with the rest of my
> constraints chop which are implemented as chops networks.
> Now is working just fine.
> I never use the Object At parameter because is a kind of black box.
> cheers
> El 2 de julio de 2010 18:15, Mark Alexander <malexander at sidefx.com>escribió:
> On 07/02/2010 06:08 AM, Pablo Giménez wrote:
>>> But when you set a reference object I got an error in the null I am using
>>> to
>>> export my channels. Middle clock in the null node force to recook and the
>>> problem seems to be solved but then  I move the target object around and
>>> the
>>> constrained is not following it.
>> This sounds like a recursion issue by the symptoms. Make sure that the
>> objects you're fetching the data from are not the same, or downstream, from
>> the object you're exporting to.
>> If this is so, the easiest solution to the problem with fetching and
>> exporting to the same object is to insert a Null above the object with all
>> the transforms, use the Object CHOP to fetch from that, and then export to
>> the actual object below.
>> Cheers,
>> M.
> --
> Un saludo
> Best Regards
> Pablo Giménez

Un saludo
Best Regards
Pablo Giménez

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